Electronic – the difference between an alternator and a generator
generator
What is the difference between an alternator and a generator ?
Best Answer
Realistically, not a lot. An electrical generator is any electro-mechanical device that converts mechanical energy (typically a spinning shaft) into electrical energy (a current). This is the exact opposite of the operation of an electric motor which converts a current (electrical energy) into mechanical energy. As such, some motors can also function as generators if the shaft is externally driven.
Generator is an umbrella term; there are various types of generators, but the only ones pertinent to your question are a dynamo and an alternator. A dynamo is a common generator used on bicycles to power lights, but it has been used for many other purposes as well. It incorporates a "commutator" which periodically switches the direction of the current flow from the rotor to the external circuitry to generate DC power.
If the commutator is removed, a dynamo is essentially an alternator producing AC power. The frequency of the resulting signal is determined by the windings of the generator and the rotational speed of the internal rotor. Technically, any generator that produces AC power is an alternator, but usually only the smaller AC generators driven by internal combustion engines (such as the one in a car) are known as such.
UPS you'd have to characterise but it's likely to be crystal controlled, so highly stable with a small but relatively constant error (within a few ppm of 50/60Hz).
Mains is subject to short term drift within strict limits : usually within 0.1 or 0.2Hz but occasionally up to 0.5Hz off, but over the longer term (an entire day or more) the error will average out to 0, higher accuracy than the crystal.
The generator is probably much less accurate or stable than either of these.
Idle speed usually means the speed at which the generator should be driven by a prime mover when there is no electrical load. A generator with no electrical load is easier to turn mechanically, so unlike your car, its idle speed is faster than its nominal speed.
An unladen generator is faster, but not as useful because it does nothing. You will want to run it at nominal (laden) speed and torque (regardless of whether it is a European or African generator), which is the speed-torque combination that provides peak efficiency for a given electrical load. The speed of the prime mover and the impedance of the electrical load are the variables you can adjust to hit maximum efficiency. Often, one cannot control the impedance, so the speed of the prime mover (perhaps a petrol engine) may be the only adjustable variable.
The nominal speed of a DC generator does not necessary match the national power supply frequency, because a DC generator outputs DC. If you use a DC generator, it's to create a DC supply for some reason, such as generating a high voltage supply to create an ex-parrot (the technical term being "voom").
Best Answer
Realistically, not a lot. An electrical generator is any electro-mechanical device that converts mechanical energy (typically a spinning shaft) into electrical energy (a current). This is the exact opposite of the operation of an electric motor which converts a current (electrical energy) into mechanical energy. As such, some motors can also function as generators if the shaft is externally driven.
Generator is an umbrella term; there are various types of generators, but the only ones pertinent to your question are a dynamo and an alternator. A dynamo is a common generator used on bicycles to power lights, but it has been used for many other purposes as well. It incorporates a "commutator" which periodically switches the direction of the current flow from the rotor to the external circuitry to generate DC power.
If the commutator is removed, a dynamo is essentially an alternator producing AC power. The frequency of the resulting signal is determined by the windings of the generator and the rotational speed of the internal rotor. Technically, any generator that produces AC power is an alternator, but usually only the smaller AC generators driven by internal combustion engines (such as the one in a car) are known as such.