Electrical Engineering

Water, wind, gravity.

This is because of two reasons:

1. Primarily because SC test is performed at rated Current(as we calculate series parameters-leakage impedance-in SC test). As the rated current on hv side is much less than lv side(VI = constant), so the rated hv side current is easily achieved(compared to lv side). Vice-versa is true for Open circuit test.

2. Also because we cannot short-circuit hv side, as, if we short-circuit hv side, V of hv side essentially falls to zero and since VI(KVA power)=constant, so the hv current will be very high(compared to low rated current on hv side), and will burn the winding.

When short-circuiting lv side, the current also increases but this increase does not burn winding due to low rated V and high rated I (You can consider the example of 220/11V)on lv side. So,SC test is performed on hv side while shorting the lv side.

Also SC test can be performed on either sides for small transformer rating. The above care must be taken for big transformer(High KVA rating)..

In the United States and most western countries, the "line frequency" is 60 Hz. (formerly referred to as 60 "cycles per second"). In European and many Asian countries, the frequency is 50 Hz.

Due to the difference in line frequencies, devices with INDUCTORS (AC motors, transformers, etc.) are NOT interchangeable between 60 and 50 Hz. power sources.

The standard line VOLTAGE in the United States started out (circa 1940s) as 110 volts. Over the years, the "standard" was increased in steps of: 110, 115, and currently (no pun intended) 120 VAC.

Again, many European and Asian countries have utility power voltages in the 220 VAC range.

Parallel, of course. Each light has to receive the full voltage - 110 or 220 Volts, depending on the region. Also, if you disconnect one light, the others should continue working. This wouldn't be the case with a series circuit.

The reheat factor in the steam turbine refers to the Thermodynamic effect on the turbine efficiency. Others factors includes the cumulative heat, and the steam turbine condition curve.

where else it would go through.....

the current entering the first resistor must pass through the next preceding resistors in order to reach the positive/+ve potential so as to complete the circuit.

Current flow is the actual flow of electrons so it goes from the ground (negative most point) to th emost positive point. lectrons are a negatve charged unit so they travel towards the positive point.

to protect the source from overloading a switch can be opened as a circuit breaker, fuse, overload protection schemes

hair dryer, cars ,lawnmower ,generator ,computer ,pool ,cleaner ,tv ,plane ,cell phone ,fans ,heaters ,remote contrl car ,boat

For DC:

Permanent magnet brush motor; (uses fixed magnets for stator fields); toys and automotive use

Shunt field motor; (field winding has many turns of fine wire in parallel with armature) small machines;

Series field motor; (field winding has few turns of heavy wire in series with armature); high speed, high torque;

Compound field motor; (has both series and shunt fields); large machinery, general purpose workhorses;

Brushless DC motors (use electronics to switch stator windings on and off, and have permanent magnet rotors) small fans and light loads.

For single phase AC:

Split Phase induction motor (2 different windings connected to supply, cage type rotor) low torque, general purpose;

Capacitor Start induction motor; (As per split phase, but with capacitor in series with starting winding) high starting torque, general purpose;

Capacitor start, Capacitor run induction motor; (as per capacitor start, but different capacitors used for starting and running) high starting and running torque, quietest running;

Shaded pole induction motor; (run winding and copper or aluminium ring around part of iron core of stator) small, cheap motors, low torque;

Universal motor; (as per series DC motor above) high torque, high speed, poor speed stability.

For 2 or 3 phase AC (star or delta connected)

Polyphase induction motor (2 or 3 identical windings on stator, cage rotor) general purpose;

Wound rotor induction motor (2 or 3 identical windings on stator, wound rotor connected in star to 3 sliprings and external resistance unit) very high starting torque, low starting current;

Synchronous motor; (standard stator, and wound rotor connected to DC supply for 'excitation' of rotor field) constant speed, power factor correction.

An ideal transformer (one with no losses, and not a bad approximation for the real thing) has an input power equal to its output power. In simple terms, since power is the product of voltage and current, then for a given value of power, as the voltage goes up, the corresponding current will go down.

To limit the current through the lamp when the gas ionises and conducts.

There is insufficient information in the question to properly answer it. You need to specify, also, the voltage, in order to determine resistance from current. Please restate the question.

Ohm's Law: Resistance = voltage divided by current.

Resistors in series add resistance to an electrical circuit. For instance two 1 ohm resistors in series will have 2 ohms of resistance.

Resistors in parallel divide the resistance between them. Thus two 2 ohm resistors in parallel will have 1 ohms total resistance.

resistors of different sizes work the same way. a 4 ohm and 2 ohm resistor in series have 6 ohms resistance. While in parallel they will have .75 ohm resistance.

resistance formulas:

series: Req = r1+r2+r3....+rx

parallel: Req = 1/r1 + 1/r2 + 1/r3 ..... +1/rx

You will need to calculate a capacitor at the output stage in order to prevent interaction with the networks connected after the output.

Current transformers are used to transform high currents to standardized values for control equipment as relays and meters.The primary winding in a current transformer is incorporated in the line and carries the current flowing in the network. The magnitude of the secondary current is dependent of the ratio of the transformer. A current transformer (CT) is a type of instrument transformer designed to provide a current in its secondary winding proportional to the alternating current flowing in its primary. They are commonly used in metering and protective relaying in the electrical power industry where they facilitate the safe measurement of large currents, often in the presence of high voltages. The current transformer safely isolates measurement and control circuitry from the high voltages typically present on the circuit being measured. The most common design of CT consists of a length of wire wrapped many times around a silicon steel ring passed over the circuit being measured. The CT's primary circuit therefore consists of a single 'turn' of conductor, with a secondary of many hundreds of turns. The CT acts as a constant-current series device with an apparent power burden a fraction of that of the high voltage primary circuit. Hence the primary circuit is largely unaffected by the insertion of the CT. Usage Current transformers are used extensively for measuring current and monitoring the operation of the power grid. The CT is typically described by its current ratio from primary to secondary. Often, multiple CTs are installed as a "stack" for various uses (for example, protection devices and revenue metering may use separate CTs). Similarly potential transformers are used for measuring voltage and monitoring the operation of the power grid.

You need a step up transformer unfortunately. Buy an Ugly's book electrical reference book. They're great and there is a transformer chart in there that will list the proper size or Kva that you will need according to your amperage need.

The ammeter is used in series, because you want to measure the current through a circuit. The voltmeter is used in parallel, because you want to measure the voltage across a circuit.

If you were to place the voltmeter in series, no current would flow because of the relatively high impedance of the voltmeter.

If you were to place the ammeter in parallel, you would create a short-circuit, due to the relatively low impedance of the ammeter.

In series, yes. In parallel, nope!

Putting a Yd1 transformer in series with a Dy11 transformer would result in the output of the Dy11 transformer being identical to the input of the Yd1 transformer with the exception of the voltage magnitude - this will change depending on the winding ratio's on both transformers.

But, in regards to other properties of the voltage, the phases will in be in phase, with the voltage in-between the two transformers lagging by 30 degrees.

The current [I] (measured in Amps) is equal to the power [P] (measured in Watts) divided by the voltage [V] (in Volts).

I = P/V

Amps = Watts / Volts

Therefore,

P*V=I

Watts * Volts = Amps

the difference is that squirl cage the rotor is short circuited while it is on operation and out of operation while the rotor of the bother one is connected to nexternal circuit to reduce the starting intial current

Phasing, or the number of phases in an electrical system has nothing to do with the voltage. A single phase and three phase supply could have a voltage supply of any given voltage from virtually 0 to infinity. Most single phase power supplies in the US are 120/208-240 volt. Three phase power supplies are typically 120/208 to 277/480 volt.