how are dc generators used for ac applications?

Question

according to my knowledge generators are dc machines but yet how are they connected in our homes/offices where ac power is used?

Answer 1

Electricity is produced by moving a rotor through an magnetic field. The electricity produced changes sinusoidally and changes polarity. This is known as AC (Alternating Current). This can be changed into DC (Direct Current) electricity by means of a half wave rectifier which uses simple electrical/electronic circuits to delete the negative part of the sinusoidal wave and leave you with just half the wave (so the name half wave rectifier), which is DC.

Answer 2

Strictly speaking, a "generator" is a DC machine, and an "alternator" is an AC machine. People refer to "generators" as anything that turns mechanical energy into electrical energy.

Alternators are usually a lot more efficient - for example cars use alternators and immediately rectify the output to produce DC. It is more efficient to create AC and then convert it to DC than to create DC directly.

The generator in your home/office more than likely is an engine with an alternator connected to it with some control circuitry in it to ensure that the voltage and frequency is what it should be.

Although it is possible to use a DC generator, and then use an inverter to create AC it would be inefficient and the quality of the AC power wouldn't be as good anyway.

Answer 3

There are various ways of mixing AC and DC:
An AC motor driving a DC generator which in turn supplies DC motors giving good torque/speed control.
A DC supply changed to AC via an inverter, solar panels would need this.
An AC supply giving a DC output via rectifiers and possibly a transformer, TV's,radios and battery chargers would use this.
An inverter can also be used to give an AC output from an AC supply but at a different frequency, for speed control of AC motors.

Answer 4

Well you already said it was a DC generator. By nature all generators generate their output voltage in cycles as they rotate, or even as they go back and forth for a "linear" generator. Therefore they generate AC, but the commutator converts this to DC. The commutator is a rotary switch that reverses the connection at the correct part of the rotation so that the current always flows one direction. That is DC, direct current instead of AC, alternating current. Sometimes AC generators may be called an Alternator. A shunt generator simply means it is self excited, that is the field magnet is connected across the generator's output, rather than having a separate DC generator for the field.

Answer 5

The word "generator" is loosely applied to any machine that turns mechanical energy into electrical. Strictly speaking those AC-making machines are alternators but most people don't bother with the distinction.

Answer 6

Most generators are AC not DC.
Conversion from one to the other is quite easy but not 100% efficient. Transmission losses are significant.
Very few high power generation system use DC, but they would include solar cell systems (photovoltaic cells.)

Answer 7

If you wish to change DC to AC from any source you would do so via an inverter

Answer 8

the reason why a dc motor can run in an ac current is because the plug or motor has a transformer , an object used for resisting current , the current is transformed and brought down to a direct current that is why it doesn't overload .
Frm Richard Jacklin , 17 yrs from south africa

Answer 9

In conjunction with an inverter.

Answer 10

Generators are a.c. they spin huge magnets usually to make the a.c. power