Electrical Engineering

A Carey-foster's bridge is a modified version of the meter bridge (wheatstone bridge or potentiometer).

It can be used to find out the average resistance per unit length of the meter bridge wire and hence find out the unknown resistance.

It is more accurate and more sensitive than a meter bridge.

All one can say without more information is that it is less than 1 and greater than zero.

AMF panel is the short form of Auto Man Failure panel. It is normally connected to the generator set to control the generator set function. It can call the generator set if the AMF further connected to the Main Switch Board ( received power from the other source - normally from the local authority ) which equipped with auto transfer switch/automatic changeover contactor. While normal supply serve to main switch board failed, the AMF board will send the power failure signal to generator set. Then the generator set will run and serve the supply to main switch board.

A motor is a mass of wires classified as a coil. Coils have a decency to generating reverse voltage when commutation the diode therefore is there for clipping this harmful back EMF

I assume "tension" in this question should be replaced with "voltage". Short circuit tests are often performed from the lower voltage side of the transformer, since a lower voltage source is then required to perform the test. Often times the test lab may not have a source that can output a high enough voltage to perform from the high voltage winding.

The importance of phase sequence is related to the direction of rotation for a motor.

The three phases set up a rotating magnetic field, which runs the motor. Reverse the sequence, and most motors will run backwards, not necessarily a good thing.

There really are only two sequences; ABC, and ACB. All other sequences are permutations of one of these.

Low-voltage switchgear may be suitable for industrial or commercial use, so long as the distribution system does not exceed 600 volts.
They may either be used alone or incorporated into a larger unit for secondary monitoring of power utilization.

Be sure to always purchase switchgear from a trusted company, and research industry standard terms of use.

If load on a generator is greater than the generator can provide, the generator will begin to slow down. If it slows down too much, it will lose synchronism.

Factories often have three phase voltage, and higher voltage (480V) compared to homes. Three phase voltage is necessary for three phase induction motors, which are often used in factories. These are very rarely used in homes. Three phase power requires more equipment than single phase (2 or three step down transformers vs. one for single phase).

Factories use higher than home voltages so wiring can be sized down and still provide the necessary power ( P = V*I ). Higher voltage equipment naturally costs more, and homes typically do not need the amount of power that would require excessively large guage wires, so it is more economical (and safer) to run lower voltage.

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1 year apperntice 3 years joneryman then masters so 4 years

what determines the amount of voltage produced by a voltaic cell?

If the wire is carrying an electrical current, and if the current has enough voltage, the current can leave the wire and pass through your body. This is painful, and can causes burns or death.

If I understand the question, a "run" capacitor is used in a squirrel-cage motor to create a phase shift in one of the windings. The result is a rotating magnetic field within the motor which causes the rotor to rotate in sympathy.

In synchronous motors, a "start" capacitor is used to create a rotating field for starting, then disconnected.

The amount of (forward biased) voltage across a diode is dependent on current and temperature. A typical silicon diode has a forward voltage of about 0.6V at low current and temperature. As current goes up, voltage goes up slightly, with a typical voltage being 1.4V at high current. As temperature goes up, voltage goes down slightly, but the maximum current rating also goes down.

Split Phase Induction (Resistance Start, Capacitor Start, Capacitor Start/Capacitor run)

Three Phase Induction

Wound Rotor Motor

Synchronous Motor

Hysteresis Motor

Reluctance Motor

Selsun Motor

Consequent Pole Motor

Inside-out Motor

Stepper Motor

Amplidyne Motor

Printed Circuit Motor

Brushless DC Motor (Pulsed DC)

Universal Motor (AC or DC)

Repulsion Motor

One Kilowatt hour is one Unit. Expressed as :- 1 KWH = I UNIT

He did not come up with the Ohm, it was named after him many years after his death.

In a delta-delta transformer, none of the actual conductors are grounded, directly or indirectly.

You do, however, always ground the casing. This is protective earth ground, or PE ground, as opposed to neutral, which is grounded at the distribution panel, but which is a current carrying conductor. PE ground is not a current carrying conductor - it is a safety ground. Some texts use the term grounded conductor to refer to neutral, and grounding conductor to refer to PE ground. Simplest designation is neutral and ground.

In summary, for a delta-delta transformer, there is no neutral, but there is always a ground. There is always a ground in any circuit, even when there is a neutral, and, except in a few special cases, those are two different connections.

You would have to know the Power Factor, normally designated PF. MVA x PF = MW.

If the PF is unity then MVA = MW. A PF of UNITY suggest the load is purely resistive with neither capacitive nor inductive components in the load or source. Of course this can mean such components have been balanced artificially.

Watts = current x volts, so you have to multiply Kw value by 1000 to get watts, then divide by the applied voltage. examples.

2Kw kettle (U.S) current = 2 x1000 divided by 120, or 16.7 amps

2Kw kettle (UK) current = 2 x1000 divided by 240 or 8.35 amps

100 watt car amplifier current = 100 divided by 12 volts = 8.5amps

when two transformer are connected in parallel condition,and the polarity of transformer are opposite to each other then a large circulating current flow through out the winding,therefore a very small current flow thro, the load .therefore lifespan of transformer will be reduced.