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A kilowatt is an unit of true power in an AC circuit -as measured by a wattmeter.

A kilovolt ampere is an unit of apparent power in an AC circuit, which is the product of the voltage across a load by the current through it.

The relationship between the two is: kilowatt = (kilovolt ampere) x (power factor of load)

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In insulators the bond energy between atoms in the material they form is very high. We need to give large energy to overcome that bond energy and set free the electrons.

As electrons are not freely available It doesnt conduct well.

There's a kind of circularity in the question. Anything that doesn't conduct electricity for any reason is called an insulator. So any substance where the electrons are too tightly bound to atoms and cannot migrate is called an insulator. Anything that manages to let electrons migrate wouldn't be called an insulator.

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if electrical panel is labeled LT, usually means its a lighting panel

LT means "Low Tension" panel. Not lighting.

Lighting panels are normally known as LDB (lighting Distribution boards)

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The watt is defined as 'the power resulting when one joule of energy is dissipated in one second'.

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If the cable is a 4 wire change the male and female ends to a 3 phase 480 with ground plug and receptacle

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Yes. It will draw approximately 5% more current than it would at 460 volts for the same power output.

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None of those materials will conduct electricity. They are therefore called insulators. However if a sufficiently high voltage is applied across an insulator it is possible that it will be damaged. This is known as the "breakdown voltage". The amount of voltage needed to cause breakdown depends mainly on its physical and chemical composition and partly on its actual thickness. For the materials stated - and provided that their surfaces are not damp or wet - the breakdown voltage is probably many thousands of volts. As can be imagined, when an insulator breaks down there will most probably be a flash of light, a loud bang and lots of smoke, maybe even a fire, so these kinds of things can only be tested safely in a properly equipped lab or maybe at your local Fire Station! The speed of electric travel thru a 'paper' capacitor or a 'plastic' capacitor is about the same (not familiar with a 'yarn' capacitor?). The main differences are the dielectric strengths of the materials which means HOW THICK do the materials have to be before the electricity will break thru it. If you meant to ask what the wire covering (yes, wire used to be covered with yarn!) does to the speed, the covering has no affect on speed.

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• lower power dissipation
• higher reliability
• lower operating voltage
• instant on (no heater warm-up time)
• smaller size
• lighter weight
• more rugged
• more efficient
• possible to integrate with other devices into one package
• etc.

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In today's culture, electricity is a vital part of functioning as a society. Simple tasks, such as waking up at a designated time or enjoying a piece of music, are accomplished currently via electronic means. One only needs to consider the consequences of a relatively short power outage – factories close down, phones and computers go dead, traffic slows to a crawl, food spoils in refrigerators – to accurately observe how power-dependent our society has become. However, electricity is a constantly developing technology, and the aspects one currently associates with electricity and electricity generation are nowhere close to the original features. In the past century and a half, electricity has steadily evolved from a scientific curiosity, to a luxury of the affluent, to a modern need. Along the way, it has been shaped by a variety of non-technological factors: economic, political, social, and environmental, to name a few.

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Electrical manometer is an electronic manometer use to record pressures between two points. It is commonly used in recording pressure in bridges.

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In general, a DCS or PLC, handles numerous discrete I/Os. One common I/O module (board) is used to supply 8, 16 or more points. Discrete output circuits from a DCS typically use low power level signals (transistors, micro relays) which cannot be sent directly to the field devices such as electromagnetic valves or motor control circuits. That is why interposing relays are often necessary.

These relays play an important role by amplifying the current capacity of the contact signal of the I/O module allowing larger current flow. In addition, discrete input circuits normally can handle only dry contacts or wet contacts of low voltage, which also require interposing relays.

For example, let's say the relay of a PLC can only accommodate 0.5A at 220 VAC, but the solenoid which is to be connected to the relay requires 1.2A at 220 VAC. In this case, an interposing relay with contacts rated for operation at 1.2A at 220 VAC would be used as an interposing relay "between" the PLC relay and the solenoid. The coil of the interposing relay should require less voltage and current than the driving relay is rated for, and the contacts of the interposing relay must be rated to handle the requirements of the load (solenoid, light, contactor, motor, etc.).

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Its circuit. But this is hard to marry with lightning, which is the path of an electric current.

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1. Describe the electrical systems you have worked on and how did you get your training?

2. What is your experience with electrical schematics?

3. What is your experience with ladder logic?

4. Describe the malfunctions you have experienced with PLC hardware?

5. Describe a tough electrical troubleshooting problem you have experienced, and briefly explain the steps you used to solve the problem.

6. What is the difference between a digital signal and an analog signal?

7. How often do you use a personal computer in a typical day? What do you do with it?

8. Describe a process problem you have experienced and how did you solve it?

9. Give an example of a tough loop you had to tune. What were the problems? And how did you solve them?

10. What brands of VFD's are you familiar with.

11. Describe some of the malfunctions associated with VFD's, and give an example of a tough VFD problem you had to solve.

12a. Using Ladder logic, write a program that will START and STOP a motor with momentary START and STOP push buttons. (Provide a sheet of paper)

12b. Add ladder logic that will turn the motor OFF after running for two minutes.

13. Describe the steps you take to troubleshoot a 3 phase, 480 volt motor that continually trips the heaters.

14a. Why is the earth pin in a 3-pin plug the longest and the thickest?

14b. Explain the purpose of grounding.

15. Describe a control panel you wired, designed, or modified. What was the purpose of the panel and state each component you used.

16. Describe the difference between a sourcing input and a sinking input.

17. Why do you want this job?

PWR 1)sensitivity of ELCB

PWR 2)about MCB ratings

PWR 3)earth resistance and earth compounds

PWR 4)what is LDR

PWR 5)your electrical activity in your society

PWR 5)CONSTRUCTION OF CAPACITOR

PWR 6)transformer and related formulas

PWR 7)industrial lightings

PWR 8)what is the nature of electrons

PWR 9)use of ballast in tube light

PWR 10)CABLE SIZE AND AMPERE RATINGS

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This is a very broad question. Every aspect of daily life was changed by the electric lightbulb and all the electrical products that followed.

Street safety

The electric streetlight was one of the first community-wide improvements to cities and towns. This increased safety and reduced crimes.

Home and Fire Safety

All homes used oil lamps or candles and most homes heated with coal and wood. Each brought fire risks in mostly wood-frame homes. Candles and lamps could easily tip over, causing fires. Sparks from fireplaces jumped protective grates.

Overheating (overfiring) of coal/wood stoves and furnaces caused numerous housefires, including through the 1970s in some areas.

Electric and gas driven furnaces reduced individual and family labor by a good 99% since they no longer had to obtain coal/wood, build a coal/wood fire, continually check on the fire, etc. As well, the house or building could stay at one consistent temperature, give or take a couple degrees. However, with wood-coal furnaces, fires went out during the night, the fire needed re-built in the morning, and it took longer to re-heat from a very cold inside temperature.

Convenience leads to personal freedom, more leisure

Women, especially, benefitted by electric power since women did most household duties. Instead of handwashing or using a manual ringer washer (which often caused injuries), washers freed women from heavy labor. Instead of hanging clothing outside to dry (although some people still prefer naturally-dried clothing), electric dryers saved time and manual labor.

Gas and electric stoves and ovens freed men and women from having to lug coal to the cook stove. Both newer stoves meant less baking times, and less fire risks with cooking.

Comfort

See above about gas / electric furnances.

Leisure

With electricity, people had more options for day, evening, and night leisure activities. Theaters and playhouses could start a show in the evening rather than just having afternoon shows. Stores could stay open longer, resulting in increased shopping and convenience. Amusement parks and circus type shows, rather than oil lamps, could add machinery ... and evenually park rides.

Transportation

In many areas, electric-run streetcars replaced horse and buggy or the most common 'transportation'-- walking.

These are just some of the ways that electricity permanently changed daily life and influenced the development of more personal products and led to vast changes in industry.

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The new headquarters will now be in Cranberry, PA. Approx 40 Minutes north of Pittsburgh

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Input

Output

Ladder Logic

Electricity

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It is the installation of ground rods at a service entrance distribution to bring the relative resistance to ground to be within 5 ohms of the utility's distribution network. This grounding system is then connected to the service distribution with a calculated size wire and connected to the distribution at a point within the distribution panel, where the service neutral wire joins the neutral bus bar.

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The use of a star delta starting is determined by the horsepower of the motor. It is the utility company that has to be asked - What is their policy on how much horsepower will they allow for across the line starting. These days pump installations usually opt for VFD controllers. This will allow the pump to ramp up to speed and ramp down in speed to stop. Using variable frequency drives totally eliminates water hammer from harming the water system. The extra cost of the VFD's is more that offset by eliminating the expensive equipment that is used to prevent water hammer.

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you would wire a float switch into the control circuit i.e, the contactor coil (which is relatively low current but rated at least for the control voltage,, in most cases 120VAC). also in the same circuit would be the overload contacts. if the overload trips and/or the float switch opens then voltage is removed from the contactor coil

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As well as motors, contactors also have kW and Ampere ratings. Have a look on the name plate of your motor and you will see its maximum current draw (amps). Select a contactor with a current rating greater than this.

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