Total 4731 registered members
Motors for dusty atmospheres – a potentially explosive development

Motors for dusty atmospheres – a potentially explosive development

Industries dealing with solids handling, like food, pharmaceuticals and chemicals, must now use hazardous area motors, like the oil and gas industries have for many years. Combustible dust can be just as explosive as gas and needs to be treated accordingly.

These days, dust is classed as a hazardous atmosphere, on par with hazardous areas with combustible gas. For instance, in the food industry, substances such as grain, cereal, sugar, flour and milk powder are classed as hazardous when they are in the form of dust. Essentially, any combustible material can be highly volatile when reduced to dust. As dust, materials have an extremely large surface area and can burn rapidly. Under some conditions, this can cause an explosion with very high energy.

Since 2006, hazardous areas with dust come under the ATEX regulations that control installations in hazardous areas. Areas with dust are classified the same way as hazardous areas with gas and equipment is selected on the same basis. But while users in the chemical, oil and gas sectors have been dealing with hazardous atmospheres for decades, this is a fairly new field for many other industry sectors.

There are two types of potentially explosive atmospheres under ATEX, Group 1 for underground mines and Group ll for surface industries

In Group ll, ATEX defines categories of equipment, specified by their protection characteristics. It also designates the hazardous zones they can be used in. Hazardous areas are divided into three zones.

Hazardous dust

Motors for areas with hazardous dust are known as Dust Ignition Proof or DIP motors, alternatively Ex tD motors.

These are used in atmospheres where explosive dust surrounds the motor, or where dust settles under its own weight on the motor. They are designed for Zones 21 and 22; no motors can be used in Zone 20 or Zone 0.

Dust is measured either as a cloud of dust or a layer of dust. The ignition temperatures for various types of dust can be obtained from commercially available reference tables. The ignition temperature for a cloud of dust must be at least 50% above the motor’s marking temperature. The ignition temperature of a 5mm layer of dust must be 75°C above the marking temperature of the motor. It is the responsibility of the user to stage maintenance periods so that the dust layer does not build up above 5mm.

To decide whether hazardous area motors are needed, the ATEX regulations requires users to draw up an Explosion Protection Document, assessing each area of the plant for hazardous gas or dust and dividing the plant into zones. An area can be declared safe only as the result of a risk assessment. Once the plant is correctly divided into zones, the appropriate equipment for each zone can be selected.

It may be tempting to try and simplify the process by using a blanket zone to cover the entire site but this could be a mistake. More expensive, over-protected equipment will have to be bought, installed and inspected. The use of over-specified equipment can have long-term financial implications, as the maintenance and repair obligations under ATEX depend on the category of equipment. Blanket zoning also raises a suspicion that the risk analysis may not have been carried out in sufficient detail.

Manufacturers’ and users’ responsibilities

ATEX 95, the product directive, and ATEX 137, the worker protection directive, cover any electrical or mechanical product or equipment that constitutes a potential source of ignition risk and which requires a special design or installation procedure to prevent an explosion.
The Product Directive, ATEX 95, concentrates on the responsibilities of the equipment manufacturer. The directive draws up the distinction between the duties of the end-user, which include the definition of the Zones, and those of the manufacturer, who will be concerned with meeting the category requirements rather than the zones.
The Worker Protection Directive, ATEX 137, concentrates on the duties of the end-user. The directive requires a consistent assessment of all measures to prevent risks of explosions and injury to people both inside and outside the plant.

Safe operation of the product or equipment is the result of cooperation between the manufacturer, the end-user and, if involved, the contractor. However, the responsibility for explosion protection of the product or equipment can never be contracted out to a third party. While the end-user is responsible for installation of products and equipment, the motor manufacturer is responsible for safety of the motors and for delivering maintenance and installation instructions.

With responsibility divided up this way, responsibility for explosion safety rests squarely with either the equipment manufacturer or the end user. Nobody else can be held responsible. The manufacturer is responsible for the equipment being safe when it leaves the factory. The end user is responsible for ensuring that it is installed, maintained and operated in such a way that it does not pose a danger of explosion.

Employers are responsible for the actions of employees and suppliers. ATEX does allow outsourcing, but the end user is responsible for the quality and the end result of such work, for instance maintenance work. When equipment is to be repaired, the end user is responsible for selecting an appropriate repair shop.
Ex motors can be repaired or rewound, but this should only be done at an approved workshop. Repairs can be carried out either to IEC guidelines or to the manufacturer’s guidelines. If it is carried out to the manufacturers’ guidelines, all warranties and original documents continue to be valid. If not, it is the end user’s responsibility to ensure that the repair job is satisfactory. At the moment, ABB is the only manufacturer to offer certified premises for hazardous area motor repairs.

Drives and hazardous area motors
Drives and hazardous area motors

Drives and hazardous area motors

Variable speed drives can be used with hazardous area motors but certain considerations need to be kept in mind. For example, a variable speed drive may create extra losses inside the motor, because of its voltage-pulse based waveform, which is different to the sinusoidal waveform produced by the 50 Hz network.

Also, the air cooling of the motor will be affected by the speed of its fan.
The drive can also be the source of other undesirable side-effects, which can include reduced motor insulation life, electromagnetic interference and bearing currents. These are effects that can be prevented and for hazardous area duty, such prevention is essential.
An ATEX compliant drive system – including motors, sensors, cabling, filters etc – should be treated as a unit. The drive affects the motor performance and the motor affects the choice of drive. Matching your own motor/drive combination can be both time-consuming and difficult. Some manufacturers can supply a ready-made solution, with combined ATEX-approved drives and motors.

Assessing the risk

The decision on whether you need to employ hazardous area motors for dust depends on the results of a risk assessment.
First of all, you will need to identify and assess fire and explosion risks of dangerous substances.
EN Standard for Group ll: Dust environments

EN 61241 -0 General requirements

EN 61241 -1 Protection by enclosures tD

EN 50281 -1-1 Dust ignition protection

Keeping working areas clean and dust free, particularly near potential ignition sources, will go a long way to reducing risks, but the best advice is to employ a professional consultant. With relevant assistance, you will be able to assess the different areas of the plant, work out the zones and draw up detailed design documentation and inspection schedules for the plant.

You will then need to eliminate or reduce the risks from the use of these substances as much as possible. This could help make the hazardous area smaller, reducing safety risks as well as the costs.

‘Equipment for use in the presence of combustible dust’. One deciding factor is the type of dust, but a host of other factors also play their roles, such as particle size, moisture content and how the dust is formed.

SOURCE: Hazardex

.

Related articles

Hydropower - Systems Overview

Hydropower - Systems Overview

Continued from first part of article:
Hydropower – Systems Overview (1)

Generator

The generator converts the rotational energy from the turbine shaft into electricity.

Efficiency is important at this stage too, but most modern, well-built generators deliver good efficiency.

Direct current (DC) generators, or alternators with rectifiers, are typically used with small household systems, and are usually augmented with batteries for reserve capacity, as well as inverters for converting the electricity into the AC required by most appliances. DC generators are available in a variety of voltages and power outputs.

AC generators are typically used with systems producing about 3 KW or more. AC voltage is also easily changed using transformers, which can improve efficiency with long transmission lines.

A view into a turbine shows a relatively large (2 feet in diameter) Pelton wheel. Peltons vary in size from 3 inches to 13 feet or more, depending on head and flow.

A view into a turbine shows a relatively large (2 feet in diameter) Pelton wheel. Peltons vary in size from 3 inches to 13 feet or more, depending on head and flow.

Depending on your requirements, you can choose either single-phase or three-phase AC generators in a variety of voltages. One critical aspect of AC is frequency, typically measured as cycles per second (cps) or Hertz (Hz).

Most household appliances and motors run on either 50 Hz or 60 Hz (depending on where you are in the world), as do the major grids that interconnect large generating stations. Frequency is determined by the rotational speed of the generator shaft; faster rotation generates a higher frequency.

In battery-based hydro systems, the inverter produces an AC waveform at a fixed frequency. In batteryless hydro systems, the turbine controller regulates the frequency.

AC Controls
At the bottom of the penstock, a manifold routes water to the four nozzles of a Harris Pelton turbine that drives a permanent magnet alternator.

At the bottom of the penstock, a manifold routes water to the four nozzles of a Harris Pelton turbine that drives a permanent magnet alternator.

Pure AC hydro systems have no batteries or inverter. AC is used by loads directly from the generator, and surplus electricity is burned off in dump loads—usually resistance heaters.

Governors and other controls help ensure that an AC generator constantly spins at its correct speed. The most common types of governors for small hydro systems accomplish this by managing the load on the generator. With no load, the generator would “freewheel,” and run at a very high rpm. By adding progressively higher loads, you can eventually slow the generator until it reaches the exact rpm for proper AC voltage and frequency.

As long as you maintain this “perfect” load, known as the design load, electrical output will be correct. You might be able to maintain the correct load yourself by manually switching devices on and off, but a governor can do a better job— automatically.

By connecting your hydro system to the utility grid, you can draw energy from the grid during peak usage times when your hydro system can’t keep up, and feed excess electricity back into the grid when your usage is low. In effect, the grid acts as a large battery with infinite capacity.
If you choose to connect to the grid, however, keep in mind that significant synchronization and safeguards must be in place. Grid interconnection controls do both. They will monitor the grid and ensure that your system is generating compatible voltage, frequency, and phase. They will also instantly disconnect from the grid if major fluctuations occur on either end. Automatic disconnection is critical to the safety of all parties. At the same time, emergency shutdown systems interrupt the water flow to the turbine, causing the system to coast to a stop, and protecting the turbine from overspeed.

DC Controls

A DC hydro system works very differently from an AC system. The alternator or generator output charges batteries. A diversion controller shunts excess energy to a dump load. An inverter converts DC electricity to AC electricity for home use. DC systems make sense for smaller streams with potential of less than 3 KW.
AC systems are limited to a peak load that is equivalent to the output of the generator. With a battery bank and large inverter, DC systems can supply a high peak load from the batteries even though the generating capacity is lower.
Series charge controllers, like those used with solar- electric systems, are not used with hydro systems since the generators cannot run without a load (open circuit). This can potentially damage the alternator windings and bearings from overspeeding. Instead, a diversion (or shunt) controller must be used. These normally divert energy from the battery to a resistance heater (air or water), to keep the battery voltage at the desired level while maintaining a constant load on the generator.

The inverter and battery bank in a DC hydro system are exactly the same as those used in battery-based, solar-electric or wind-electric systems. No other special equipment is needed. Charge controller settings may be lower than used in typical PV and wind systems, since hydro systems are constant and tend to run with full batteries much of the time.

Head, Flow, & Efficiency

If you expect to sell electricity back to the utility, pay extra attention to the efficiency of your hydro system because higher output and a lower cost-per-watt will go straight to your bottom line. Your turbine manufacturer can give you guidance on the most efficient design, as well as grid interconnection controls and safeguards. If you’re off- grid, and your site doesn’t have lots of head and flow, high efficiency can make the difference between ample electricity for your needs and having to use a backup, gasoline- powered generator.

Click on turbine images to see enlarged:
A Canadian-made Energy Systems and Design turbine uses a permanent magnet alternator and a turgo runner.

A Canadian-made Energy Systems and Design turbine uses a permanent magnet alternator and a turgo runner.

A Power Pal turbine with a Francis runner direct-coupled to the alternator

A Power Pal turbine with a Francis runner direct-coupled to the alternator

The 4-inch (10 cm) turgo runner in an Australian-made Platypus turbine.

The 4-inch (10 cm) turgo runner in an Australian-made Platypus turbine.

The underside of a low-head, high-flow Nautilus turbine showing the Francis runner, and above it, the innovative nautilus-shaped headrace.

The underside of a low-head, high-flow Nautilus turbine showing the Francis runner, and above it, the innovative nautilus-shaped headrace.

Whether a hydro system generates a few watts or hundreds of megawatts, the fundamentals are the same. Head and flow determine how much raw water power is available, and the system efficiency affects how much electricity will come out the other end. Each component of a hydro system affects efficiency, so it’s worthwhile to optimize your design every step of the way.

More Hydro Terms
Pipe LossPressureReaction TurbineRunner
Frictional Head Loss: Refers to the quantity of water supplied from a water source or exiting a nozzle per unit of time. Commonly measured in gallons per minute (gpm).A type of reaction hydro-turbine used in low to medium heads. It consists of fixed vanes on a shaft. Water flows down through the vanes, driving the shaft.Lost energy due to pipe friction. In hydro systems, pipe sized too small can lead to serious friction losses.The difference in elevation between a source of water and the location at which the water from that source may be used (synonym: vertical drop). Expressed in vertical distance or pressure.
TailraceTrash RackTurgo
A flume or channel that feeds water into a hydro turbine.Any electricity that is generated by the flow of water.Turbines with runners that operate in air, driven by one or more high-velocity jets of water from nozzles. Typically used with moderate- to high- head systems. Examples include Pelton and turgo.

SOURCE: Dan New, homepower.com

.

Related articles

Hydropower - Systems Overview

Hydropower - Systems Overview

Hydropower is based on simple concepts. Moving water turns a turbine, the turbine spins a generator, and electricity is produced. Many other components may be in a system, but it all begins with the energy already within the moving water.

What Makes Water Power

Water power is the combination of head and flow. Both must be present to produce electricity. Consider a typical hydro system. Water is diverted from a stream into a pipeline, where it is directed downhill and through the turbine (flow). The vertical drop (head) creates pressure at the bottom end of the pipeline. The pressurized water emerging from the end of the pipe creates the force that drives the turbine. More flow or more head produces more electricity. Electrical power output will always be slightly less than water power input due to turbine and system inefficiencies.

Head is water pressure, which is created by the difference in elevation between the water intake and the turbine. Head can be expressed as vertical distance (feet or meters), or as pressure, such as pounds per square inch (psi). Net head is the pressure available at the turbine when water is flowing, which will always be less than the pressure when the water is turned off (static head), due to the friction between the water and the pipe. Pipeline diameter has an effect on net head.

Flow is water quantity, and is expressed as “volume per time,” such as gallons per minute (gpm), cubic feet per second (cfs), or liters per minute. Design flow is the maximum flow for which your hydro system is designed. It will likely be less than the maximum flow of your stream (especially during the rainy season), more than your minimum flow, and a compromise between potential electrical output and system cost.

Head and flow are the two most important things you need to know about your site. You must have these measurements before you can seriously discuss your project, how much electricity it will generate, or the cost of components. Every aspect of a hydro system revolves around head and flow. In Part 2 of this series, we will discuss how to measure them.

Power Conversion & Efficiency

The generation of electricity is simply the conversion of one form of energy to another. The turbine converts the energy in the moving water into rotational energy at its shaft, which is then converted to electrical energy by the generator. Energy is never created; it can only be converted from one form to another. Some of the energy will be lost through friction at every point of conversion. Efficiency is the measure of how much energy is actually converted. The simple formula for this is:

Net Energy = Gross Energy x Efficiency

While some losses are inevitable as the energy in moving water gets converted to electricity, they can be minimized with good design. Each aspect of your hydro system—from water intake to turbine-generator alignment to transmission wire size—affects efficiency. Turbine design is especially important, and must be matched to your specific head and flow for best efficiency.
A hydro system is a series of interconnected components. Water flows in at one end of the system, and electricity comes out the other. Here is an overview of these components, from the water source to the electrical controls.

Water Diversion (Intake)
This variable-flow, crossflow turbine uses a belt-drive coupling to a 40 KW synchronous generator. It supplies electricity to a coffee processing plant in Panama.

This variable-flow, crossflow turbine uses a belt-drive coupling to a 40 KW synchronous generator.

The intake is typically the highest point of your hydro system, where water is diverted from the stream into the pipeline that feeds your turbine. A diversion can be as simple as a screened pipe dropped into a pool of water, or as big and complex as a dam across an entire creek or river. A water diversion system serves two primary purposes.

The first is to provide a deep enough pool of water to create a smooth, air-free inlet to your pipeline. (Air reduces horsepower and can damage your turbine.) The second is to remove dirt and debris.

Trash racks and rough screens can help stop larger debris, such as leaves and limbs, while an area of quiet water will allow dirt and other sediment to settle to the bottom before entering your pipeline. This helps reduce abrasive wear on your turbine.

Another approach is to use a fine, self-cleaning screen that filters both large debris and small particles.

Pipeline (Penstock)
Elements of a Hydroelectric System

Elements of a Hydroelectric System

The pipeline, or penstock, not only moves the water to your turbine, but is also the enclosure that creates head pressure as the vertical drop increases. In effect, the pipeline focuses all the water power at the bottom of the pipe, where the turbine is. In contrast, an open stream dissipates the energy as the water travels downhill.

Pipeline diameter, length, material, and routing all affect efficiency. Guidelines are available for matching the size of your pipeline to the design flow of your system. As you’ll see in the next article in this series, a small-diameter pipeline can considerably reduce your available horsepower, even though it can carry all available water.Larger diameter pipelines have less friction as the water travels through.

Powerhouse

The powerhouse is simply a building or box that houses your turbine, generator, and controls. Its main function is to provide a place for the system components to be mounted, and to protect them from the elements. Its design can affect system efficiency, especially with regard to how the water enters and exits your turbine. For example, too many elbows leading to the turbine can create turbulence and head loss.

Likewise, any restrictions to water exiting the turbine may increase resistance against the turbine’s moving parts.

Turbine
An in-stream screen keeps debris and silt out of the penstock at the small-stream intake for a microhydro system in Washington.

An in-stream screen keeps debris and silt out of the penstock at the small-stream intake for a microhydro system in Washington.

The turbine is the heart of the hydro system, where water power is converted into the rotational force that drives the generator. For maximum efficiency, the turbine should be designed to match your specific head and flow. There are many different types of turbines, and proper selection requires considerable expertise. A Pelton design, for example, works best with medium to high heads. A crossflow design works better with lower head but higher flow. Other turbine types, such as Francis, turgo, and propeller, each have optimum applications.

Turbines can be divided into two major types. Reaction turbines use runners (the rotating portion that receives the water) that operate fully immersed in water, and are typically used in low to moderate head systems with high flow. Examples include Francis, propeller, and Kaplan.
Impulse turbines use runners that operate without being immersed, driven by one or more high-velocity jets of water. Examples include Pelton and turgo. Impulse turbines are typically used with moderate-to-high head systems, and use nozzles to produce the high-velocity jets. Some impulse turbines can operate efficiently with as little as 5 feet (1.5 m) of head.

The crossflow turbine is a special case. Although technically classified as an impulse turbine because the runner is not entirely immersed in water, this “squirrel cage” type of runner is used in applications with low to moderate head and high flow. The water passes through a large, rectangular opening to drive the turbine blades, in contrast to the small, high-pressure jets used for Pelton and turgo turbines.
Regardless of the turbine type, efficiency is in the details. Each turbine type can be designed to meet vastly different requirements. The turbine system is designed around net head and design flow. These criteria not only influence which type of turbine to use, but are critical to the design of the entire turbine system.

Minor differences in specifications can significantly impact energy transfer efficiency. The diameter of the runner, front and back curvatures of its buckets or blades, casting materials, nozzle (if used), turbine housing, and quality of components all affect efficiency and reliability.

Drive System

The drive system couples the turbine to the generator. At one end, it allows the turbine to spin at the rpm that delivers best efficiency. At the other, it drives the generator at the rpm that produces correct voltage and frequency— frequency applies to alternating current (AC) systems only. The most efficient and reliable drive system is a direct, 1:1 coupling between the turbine and generator.

This is possible for many sites, but not for all head and flow combinations. In many situations, especially with AC systems, it is necessary to adjust the transfer ratio so that both turbine and generator run at their optimum (but different) speeds. These types of drive systems can use either gears, chains, or belts, each of which introduces additional efficiency losses into the system. Belt systems tend to be more popular because of their lower cost.

Hydro Terms
FlowFrancis TurbineFriction LossHead
Refers to the quantity of water supplied from a water source or exiting a nozzle per unit of time. Commonly measured in gallons per minute (gpm).A type of reaction hydro-turbine used in low to medium heads. It consists of fixed vanes on a shaft. Water flows down through the vanes, driving the shaft.Lost energy due to pipe friction. In hydro systems, pipe sized too small can lead to serious friction losses.The difference in elevation between a source of water and the location at which the water from that source may be used (synonym: vertical drop). Expressed in vertical distance or pressure.
HeadraceHydroelectricityImpulse TurbineIntake
A flume or channel that feeds water into a hydro turbine.Any electricity that is generated by the flow of water.Turbines with runners that operate in air, driven by one or more high-velocity jets of water from nozzles. Typically used with moderate- to high- head systems. Examples include Pelton and turgo.The structure that receives the water and feeds it into the penstock (pipeline). Usually incorporates screening or filtering to keep debris and aquatic life out of the system.
Pelton WheelPenstock
A common impulse turbine runner (named after inventor Lester Pelton) made with a series of cups or “buckets” attached to a hub.The pipe in a hydro system that carries the water from the intake to the turbine.

To be continued soon in next article: Hydropower – Systems Overview (2)

SOURCE: Dan New, homepower.com

.

Related articles

ABB i-bus KNX - Constant lighting control

ABB i-bus KNX - Constant lighting control

Lighting in modern buildings is more than a basic requirement – it can play an important role in the architectural design and the energy efficiency of the building, not to mention the health, safety and well being of the occupants.

With an impressive spectrum of products for the control, measurement, regulation and automation of lighting, ABB i-bus® EIB / KNX can perform challenging lighting tasks.

The following elaboration on the topic of constant lighting control should provide adequate background information to:
- better understand the method of operation of a constant lighting control
- ensure optimum placement of the light sensors required to detect the actual value
- recognise critical ambient conditions which interfere with the function of the constant lighting control
- evaluate the physical limitations to which a constant lighting control is subject.

For this purpose it is necessary to understand the most important terms used in the field of lighting technology.

How does constant lighting control function?

In constant lighting control a light sensor installed on the ceiling measures the luminance of the surfaces in its detection range, e.g. the floor or the desks.

How does constant lighting control function?

This measured value (actual value) is compared with the predefined setpoint value, and the control value is adjusted so that the divergence between the setpoint and actual values is minimal. If it is brighter outside, the share of artificial lighting is reduced. If it is darker outside, the share of artificial lighting is increased. The exact function of the light controller is described in detail in the manual of the Light Controller LR/Sx.16.1.
A Luxmeter placed underneath the light sensor, e.g. on a desk, is used for setting the setpoint. This Luxmeter detects the degree of illumination which illuminates the surfaces underneath the light sensor.

The objective of a constant lighting control is to retain the set degree of illumination when a setpoint is set. To perfectly implement this objective, the light sensor should be placed exactly on the spot where the Luxmeter was placed to adjust the setpoint value, in order to also determine the degree of illumination. As this is not possible for practical reasons, the light sensor is generally mounted on the ceiling.

This is a compromise. For the reference setting of the setpoint, a Luxmeter is used for measurement of the degree of illumination; however, the light controller primarily detects the luminance underneath the light sensor. In this way the light controller indirectly maintains a constant degree of illumination. If certain constraints are not observed with indirect measurement, it can mean that the constant lighting control will not function or not function as required.

This is not a specific phenomenon just affecting our constant lighting control, but rather is the case for all constant lighting controls.

What is the difference between degree of illumination and luminance?

In order to fully appreciate the problems relating to indirect measurement, it is necessary to examine the most important terms used in lighting technology. Only the basic terms are explained and we will forego a more exact and detailed explanation or mathematical derivation of more complex terms, e.g. luminous intensity = luminous flux/steradian.
A luminary, e.g. a fluorescent tube, converts electrical energy to light. The light rays emitted by a light source (luminous exitance) are referred to as a luminous flux. The unit is the Lumen [lm]. Luminaries convert the input energy to light at varying degrees of efficiency.

CategoryTypeOverall luminous
efficency (lm/w)
Overall luminous
efficency
.Incadescent lamp.5 W incandescent lamp.5.0.7%
.40 W incandescent lamp.12.1.7%
.100 W incandescent lamp.15.2.1%
.Glass halogen.16.2.3%
.Quartz halogen.24.3.5%
.High temperature incandescent lamp .35.5.1%
.Fluoroscent lamp.5 – 26 W energy saving light bulb.45 – 70.6.6 – 10.3%
.26 – 70 W energy saving light bulb.70 – 75.10.3 – 11.0%
.Fluorescent tube with inductive ballast.60 – 90.7%
.Fluorescent tube with electronic ballast.80 – 110.11 – 16%
.Light emitting diode.Most efficient white LEDs on the market.35 – 100.5 – 15%
.White LED (prototype, in development).up to 150.up to 22%
.Arc lamp.Xenon arc lamp.typ. 30 – 50;
.up to 150
.4.4 – 7.3%;
.up to 22%
.Mercury Xenon arc lamp.50 – 55.7.3 – 8.0%
.High pressure mercury vapour lamp.36 (50W HQL) –
.60 (400W HQL)
.up to 8.8%
.Gas discharge lamp.Metal halide lamp.93 (70W HCI) –
.104 (250W HCI)
.up to 15%
.High pressure sodium lamp.150.22 %
.Low pressure sodium lamp.200.29%
.1400 W sulphur lamp.95.14%
.Theoretical maximum .683.100 %

In addition to the luminous flux there is the item luminous intensity, also referred to as the lumi- nous flux density. The luminous intensity is measured in Candelas [cd]. The Candela is a mea- surement unit for luminous intensity emitted by a light source in a particular direction. An exact definition will lead to a complex mathematical analysis, e.g. the explanation of a steradiant.

Simplification: A luminous intensity of 1 cd corresponds to the measured degree of illumination of 1 lx at a distance of 1 m from the light source.

The luminous flux emitted by the light source illuminates the surfaces that it meets. The intensity with which the surfaces are illuminated is referred to as the degree of illumination. The degree of illumination depends on the magnitude of the luminous flux and the size of the surfaces.
It is defined as follows:

E = Φ/ A [lx=lm/m2]

E = degree of illumination
Φ = luminous flux in lm
A = illuminated surface

In accordance with the above table, a 100 W incandescent lamp with 15 lm/W generates a maximum luminous flux of 1500 lm. If the entire luminous flux of the incandescent lamp is not emitted in a spherical manner into the room, but rather concentrated and distributed evenly on a surface of 1 m2, then the value for the degree of illumination at every point on the surface would be 1500 lx.

The perceived brightness of an illuminated surface depends on the illuminated surface and the reflectance of the illuminated surfaces. The reflectance is the reflected share of the luminous flux from the illuminated surface. Typical values for the reflectance are:

  • 90% highly polished silver
  • 75% white paper
  • 65% highly polished aluminium
  • 20% – 30% wood
  • < 5% black satin

The perceived brightness of an illuminated surface or a self-illuminating surface, e.g. an LCD monitor, is designated as the luminance. The unit of luminance is cd/m2.

If white paper is subject to a degree of illumination of 500 lx, then the luminance is about 130 – 150 cd/m2. At the same degree of illumination, environmentally-friendly paper has a luminance of about 90 – 100 cd/m2.

On what does the luminance measured by the light sensor respectively the measured value of the light sensor depend?

The luminance “primarily” detected by the light sensor depends on different criteria. It depends on the degree of illumination which the surfaces in the detection range of the light sensor are illuminated. The higher the degree of illumination, the higher the luminance of the illuminated surfaces.
The same applies for the reflectance of the surfaces. The higher the reflectance, the higher the luminance of the surfaces and thus the measured value of the sensor. The measured value of the sensor is the actual value used for lighting control.

The installed height of the sensor also plays a role. If the light sensor was an ideal “luminance measurement device”, then the luminance which it measures would be indepen- dent of the installation height of the light sensor. As this is not the case, the measured value of the sensor decreases as the installation height increases.

SOURCE: ABB | Practical Knowledge: ABB i-bus® KNX Constant lighting control

.

Related articles

5,290 views

ePlusMenuCAD 9 - New Polished Version

ePlusMenuCAD 9 - Advanced Electrical Design Tool

ePlusMenuCAD 9 is finally released! Since version 3, ePlusMenuCAD has been changed and improved a lot, and now, version 9 is fine polished and most complete version so far.

There are many improvements and some new things that will be very usefull to designers.

Many electrical designers use AutoCAD platform in their daily work. ePlusMenuCAD is an integrated tool within AutoCAD which contains almost every aspect of electrical design.

Few Words About ePlusMenuCAD 9

ePlusMenuCAD is a software tool for professonal electrical design in AutoCAD environment. If you do electrical design using AutoCAD, then you certainly know how much time you lose on inserting varius blocks of luminaires, sockets, panels, generating technical specifications, drawing single line diagrams, etc.

If you use your own blocks in AutoCAD which are placed somewhere on your HDD and insert them when needed in the drawing, and after that manually copy each time  – then ePlusMenuCAD is for you. All the symbols are placed in one place, available from the drop-down menu , 26 toolbars, and also from intuitive shorcuts from command line. No more boring inserting and copyng blocks! ePlusMenuCAD offers efficency and high speed in generating technical specifications for Bill of Quantities, as well as automation in inserting electrical symbols into drawing.

In ePlusMenuCAD there are two modules integrated: Mosaic Design and X-functions. Mosaic Design is advanced tool for creating single line diagrams and application diagrams. Large database of (universal) symbols covers almost any kind of scheme. Insertion of symbols and feeders, and generation of BOM is completely automated and very easy for use in drawing. Second module X-functions, has more than 50 extra usefull functions (commands) that saves a lot of time durin daily work in AutoCAD. Working with layers, blocks, polylines  etc. is much much easier .

ePlusMenuCAD can be translated in to two languages English and Serbian/Croatian.

Example

Example of using ePlusMenuCAD in project Hotel Splendid in Budva (Montenegro), where it was used for designing lighting, power distribution,  technology, installations of sockets and single line diagrams.
ePlusMEnuCAD - Hotel Splendid - energetski razvodePlusMenuCAD - Hotel Splendid - tehnička specifikacijaePlusMenuCAD - Hotel Splendid - osvetljenjeePlusMenuCAD - Hotel Splendid - tehnologijaePlusMenuCAD - Hotel Splendid - utičnice

AutoCAD support

AutoCAD versions 2006, 2007, 2008, 2009 and 2010 are fully supported, and ePlusMenuCAD can be installed and used simultany on this versions. That means that ones ePlusMenuCAD is installed, you can use it in all (supported) installed AutoCAD versions.

Conception
Drop-down menu (click to enlarge)

ePlusMenuCAD drop-down menu (click to enlarge)

More than 1200 electrical symbols are placed in its categories (outlets, luminaires, types of installation, DEA, Cable verticals, labels of cables, transformers, cable feeds, TKS, EIB KONNEX ..). Every category has its layer. Layers carry the prefix “EnJS_” and “EnTS_” so that can be easily sorted in Layer Manager in the AutoCAD.

Also, there are a lot of various types of luminaires from metal-halid throug incadescent sorted by category and with predict shortcuts from the command line. Lamps that are designed to be supplied rom Diesel Agregate DEA, have cross symbol, and as such are also located in generated technical specification. Almost every area in which there are elements is covered with IEC symbols.

Drop-down menu is well organized, all symbols and functions are divided into categories, the most important are shown below:

Electrical distribution of power
• Predefined types of power supply lines (network, aggregate, UPS, diesel supply…)
• Power transformers – dry type and distribution oil transformers (with and without conservator) typical powers 630, 1000, 1600, 2000, 2500 and 3200kVA
• Distribution boards and panels, panels supplied from diesel agregate, and all with labels
• Cable or busbar vertical runs with their labels of incoming or outgoing connections
• Predefined labels for the cables in the colors (to distinguish cables of differnt type and supply…)

Installation of power sockets
• Power sockets 2P and 3P in the IEC variations and variations GOST standards (Russian standard)
• TV, antenna, computer plug and terminal space in the floor, fan-coil connection…
• Thermostats, rails for the main and additional equipotential deuce …
• Cable feeds for direct consumers, in wall and ceiling (2P, 3P), luminaires

Power and distribution transformers 10-20/0, 4kV
• Dry type transformer, powers: 630kVA – 3200kVA
• Oil type transformers, powers: 630kVA – 2500kVA with and without conservator

Installation of earthing
• Vertical runs of FeZn earthing bar (predefined in various colors)
• Tables for power sockets, cable feeds, lamps, and elements of Earthing with predefined default values

Legends
• Legends for the power sockets, luminaires, electric distribution and cables (2p and 3p)
• Stamp basis (the ability to post the logo of your company)
• Unique symbol of current round ECM
• The automatic marking ECM and (increasing, decreasing or all of the same series)

Installation of lighting
• Fluoroscent lamps built-in and built-on, powers from 1x18W to 4x36W with DEA symbols
• Fluroscent tubes, powers from 1x18W to 2x36W
• Fluo-compact lamps built-in and built-on, powers from 1x9W to 2x36W with DEA symbols
• Incadescent lamps, built-in and built-on, powers from 40W to 100W with DEA symbols
• Incadescent-reflect lamps, built-in and built-on, with DEA symbols
• Halogen lamps built-in and built-on, powers from 20W to 1000W with DEA symbols
• Metal-halid lamps built-in and built-on, powers from 70W do 2000W with DEA symbols
• Reflectors
• Crystal chandeliers for the salons and kitchen
• Decorative lamps for billiard tables, halls, theaters…
• Lamps for outdoor lighting (pillars, underwater lamps …)
• Anti-panic lamp
• Sensors and feeds the optical cable …
• Installation switches, 2p, 3p, alternate, serial …
• Dimers, tasters…

Telecommunications and signal systems
• predefined types of installations (fire, access control, anti-burglary, structural wiring…)
• Anti-burglary
• Anti-fire
• Access control
• Video surveillance – CCTV
• TV and Radio
• Phone and intercom
• Clock
• Gas
• Audio-Video Systems
• Speakers
• Power supply
• Wireless transfer of information

EIB KONNEX
• Instabus elements (system, input / output, lighting, heating / cooling, display, infrared …)

What can be designed with ePlusMenuCAD?
Electric systems up to 1000V
Designing transformer substations 20/10/6/0,4 kV
Installations of power sockets (+ IEC symbols)
Installations of power distribution (+ cable labels)
Single line diagrams and application schemes of switchgears 0,4 kV
Reserv power supply (Diesel agregate, UPS system)
External cable distribution 20/10/6/0, 4 kV
Installation of interior lighting (general, technology and decorative)
Installation of external lighting (lighting roads, promenades, courts …)
Installation of lighting open trade centers and parking space
Installation of decorative lighting for public facilities and open sports facilities
Lightning protection
Earthing system
Technological installations
Telecommunications and signaling systems
Telephone system and installations
Intercom system and installations
Systems and installations for reception and distribution R / TV
Speaker systems
Anti-fire system and installations
Anti-burglary system and installations
Access control system
Hotel management system
Clock system
Conference system
Gas detection system
Wireless information transfer system

Highlights:

Mosaic DesignMOSAIC DESIGN: ePlusMenuCAD is fully capable to draw single line diagrams and application schemes using built-in modul Mosaic Design. Main feature is the fact that all pages of scheme are in one DWG drawing, and that user can create complete distributive or motor feeders in a minute, just by picking on one of the many predefined feeders.User can also plot one or  one hunderd and one scheme just with one click. All elements and feeders are intuitive sorted in iNteLLi Elements, with options of zoom preview of each element or feeder. Mosaic Design runs when you open one of it’s templates from default folder (new drawing). There are several offered templates that are copied during installation of ePlusMenuCAD in default AutoCADs template folder. Now, all you have to do is to choose one  template and Mosac Design module will be automatically loaded, and you can use any command from the menu or a toolbar. You can also simply change existing template and save it as your own template .

Scale FactorSCALE FACTOR: All symbols (blocks) in ePlusMenuCAD are defined by ScaleFactor. This is the scale of symbols with respect to the drawing. Default value is 1, but it can be changed at any time to any positive value. Symbols of electric current mark ECM and tables of power sockets and luminaires have scale factor SFecm, and symbol of junction box has its scale factor SFjb. In this way, you can intelligently control the scale of symbols in the drawing. Scale can therefore  be changed very easy. If you don’t want to think about the Scale Factor, then set the Master SF to some value that applies to all drawings.

InfoIt ProInfoIt PRO: Is a function to be used for generating Bill of Quantaties as well as for getting a lot of information about the symbols in the drawing. What can you do with InfoIt? You can take out a detailed technical specification from DWG drawing, calculate installed single-phase and three-phase el. powers of sockets and cable feeds from their tables, export report to MS Word, take out a list of all non-ePlusMenuCAD blocks, take out all luminaires by tags. InfoIt PRO is integrated part of ePlusMenuCAD. InfoIt Database is a unique datsbase of blocks that are within ePlusMenuCAD, and it offers the possibility to add your own symbol definitions – your own blocks . It is also possible to edit descriptions of all blocks in the InfoIt Database.

iNaLL Professional 6iNaLL Professional 6: A unique tool for every-day work in AutoCAD. It can make changes in the content of text objects TEXT, MTEXT, ATTRIBUTE, BLOCK, DIM. Inall PRO can store any text that you select into internal memory, so you can use it later in some other drawing. It has the support of the Serbian latin letters ČĆĐŠŽ, as well as all Russian letters, which can be used with any font. You can also import content of any text file into iNaLL PROs memory and use it for pasting in text  objects in drawing.

Download link: Here

.

Related articles

ABB Technical Guides

ABB - 10 Technical Guides

Na stranici ABB Technical Guides su postavljeni tehnički vodiči (eng. Technical Guides) koje je objavio proizvođač opreme ABB. Postavljeno je 10 tehničkih vodiča koji se uglavnom bave temom frekventnih regulatora, upravljanjem motorima i slično.

Pored tehničkih vodiča, tu su i uputstvo za ekstruder sa AC motorima i uputstvo za korišćenje frekventnih regulatora u aplikaciji sa pumpama. Na ovoj strani se nalazi i e-knjiga Technical guide book u kojoj je nalazi veliki broj odgovora na važna pitanja.

ABB Drives: Technical Guides

  • Technical Guide 01 – Direct Torque Control
  • Technical Guide 02 – EU Council Directives and adjustable speed electrical power drive .systems
  • Technical Guide 03 – EMC compliant installation and configuration for a power drive .system
  • Technical Guide 04 – Guide to Variable Speed Drives
  • Technical Guide 05 – Bearing Currents in Modern AC Drive Systems
  • Technical Guide 06 – Guide to Harmonics with AC Drives
  • Technical Guide 07 -Dimensioning of a Drive system
  • Technical Guide 08 -Electrical Braking
  • Technical Guide 09 -Guide to motion control drives
  • Technical Guide 10 -Functional safety
  • Application Guide to extruders in AC drives
  • Application Guide – Using variable speed drives (VSDs) in pump applications
  • ABB Drives – Technical guide book

Link: ABB Technical Guides

.

Related articles

ePlusMenuCAD 9 padajući meni

ePlusMenuCAD 9 padajući meni

ePlusMenuCAD je od verzije 3 pretrpeo puno izmena i poboljšanja. Nova verzija 9 predstavlja ispoliranu verziju sa zaista puno ispravljenih i poboljšanih funkcija.

Projektantima će sada biti na raspolaganju (pored proračuna pada napona i preseka kabla i fotometrijskog proračuna) i proračun zaštite od atmosferskog pražnjenja, tj. gromobranske zaštite, kao i nekoliko novih i korisnih funkcija kao što su de-instaler iz AutoCAD-a, CLO zatvaranje svih crteža, RAM standardni okvir za crteže…

Budući da je sa verzijom 9 postavljena i nova cena programa, svima koji su hteli da kupe licencu, CsanyiGroup nudi da do 15.12.2009 kupe licencu ePlusMenuCAD 9 po staroj ceni od 180EUR. Od ove verzije, nadogradnja tj. update na novu verziju je besplatan (u okviru iste verzije, 9).

Stara cena važi do 15.12.2009. Iskoristi priliku!

Par reči o ePlusMenuCAD 9:

Integriše unutar AutoCAD-a u obliku padajućeg menija, kao i 26 paleta sa alatima, tj. toolbar-ova koji se uključuju po potrebi. Svi simboli kojih ima preko 1200 se nalaze u svojim katergorijama (priključnice , osvetljenje, tipovi instalacija, DEA, vertikale, oznake kablova, transformatori, kablovski izvodi, TKS, EIB KONNEX ..), i kao takvi se nalaze u svojim lejerima. Lejeri nose prefix „EnJS_“ i „EnTS_“ tako da se lako sortiraju u Layer Manager-u u AutoCAD-u. Svi elementi u programu mogu biti u lejerima na srpskom ili engleskom jeziku u zavisnosti od potreba korisnika.

Verzije AutoCAD 2006, 2007, 2008, 2009  i 2010 su potpuno podržane i ePlusMenuCAD™ se može nesmetano instalirati i koristiti na ovim platformama. Jednom kada se instalira u Windows-u, ePlusMenuCAD™ se može koristiti istovremeno u svim podržanim verzijama AutoCAD-a koje imate instalirane na računaru.

Mogućnosti:
  • 2 podržana jezika – srpski i engleski
  • Proračun pada napona i potrebnog preseka kabla
  • Fotometrijski proračun na crtežu
  • Proračun zaštite od atmosferskog pražnjenja – gromobranska zaštita
  • Jednopolne i šeme delovanja sa veikom bazom simbola i kompletnih distributivnih i motornih izvoda
  • Detaljna tehnička specifikacija – generisanje izvešataja sa naprednim opcijama
  • Energetski razvod (napajanje, mreža, agregat, UPS, transformatori, razvodni ormani …)
  • Instalacije priključnica (2P i 3P priključnice, kablovski izvodi… u IEC i GOST standardima)
  • Energetski i distributivni transformatori (suvi i uljni sa i bez konzervatora)
  • Instalacije uzemljenja (Vertikale FeZn trake, var traka-traka…)
  • Legende i pečat (predefinisane legende za en. razvod, priključnice, osvetljenje, strujni krug…)
  • Instalacije osvetljenja (fluoroscentne, inkadescentne, halogene… sa svojim DEA simbolima…)
  • Telekomunikacioni sistemi (protivprovala, protivpožar, kontrola pristupa, CCTV, ozvučenje…)
  • Instabus elementi (sistem, input-output, lighting, heating/cooling, display, infrared …)
  • Preko 100 jako korisnih funkcija za brži i automatizovani rad u AutoCAD-u
  • Galerija opštih simbola (ljudi, kompjuterska oprema, paneli…)

Pored svih navedenih mogućnosti, insertovanje simbola je potpuno automatizovano i jednostavno. Praktično, projektant će dosta vremena uštedeti zahvaljujući tehnologiji insertovanja i generisanja izveštaja sa crteža. Velika paleta simbola u ePlusMenuCAD-u sigurno ispunjava i najveće zahteve projektanata.

Primer:

Primer korišćenja ePlusMenuCAD™-a na osnovama tehnologije, razvoda, priključnica, osvetljenja, gromobrana itd. Prikazani delovi osnova su iz projekta Hotel Splendid u Budvi – Crna Gora u kojem je korišćen ePlusMenuCAD za projektovanje el. instalacija.

ePlusMenuCAD – Korisni linkovi:

.

Related articles