ac brushless generator?

Question

anybody could give me some answers...
what is the difference between ac brushless generator and non-brushless generator?? how about PMG generator??
how to improve torque in dc motor??
please anybody..??

Answer 1

pl. visit:
www.aaroncake.net/forum/topic.asp?TOPIC_ID=5817
http://www.engineersedge.com/motors/ac_dc_generator_excitors.htm
for brushless generator.
An excitation system for a brushless generator having a main generator portion including a field winding disposed on a rotor and an armature winding disposed in a stator includes an exciter portion having a set of polyphase exciter field windings disposed in the stator and an armature winding disposed on the rotor and coupled to the main generator portion field winding. A first power converter is coupled to the main generator armature winding and a second power converter is coupled to the set of polyphase exciter field windings. Contactors are operable in a starting mode of operation to couple a source of electrical power to the first and second power converters and are operable in a generating mode to disconnect the source of electrical power from the first and second power converters. A control unit controls the power converters such that the power converters provide AC power to the main generator armature winding and to the set of polyphase exciter field windings during operation of the starting mode so that the rotor is accelerated. The control unit operates the power converters in the generating mode such that the second power converter provides AC power to the set of polyphase exciter field windings and the first power converter develops constant-frequency AC power.
(PMG:Permanent Magnet Alternators:
Advantages: Low cost per watt of output, very efficient, huge power output possible, extremely sturdy construction
Disadvantages: A time-consuming, somewhat complicated project, machining needed.
Suitability for Wind Power: GOOD )
-A torque motor is a specialized form of induction motor which is capable of operating indefinitely at stall (with the rotor blocked from turning) without damage. In this mode, the motor will apply a steady torque to the load (hence the name). A common application of a torque motor would be the supply- and take-up reel motors in a tape drive. In this application, driven from a low voltage, the characteristics of these motors allow a relatively-constant light tension to be applied to the tape whether or not the capstan is feeding tape past the tape heads. Driven from a higher voltage, (and so delivering a higher torque), the torque motors can also achieve fast-forward and rewind operation without requiring any additional mechanics such as gears or clutches. In the computer world, torque motors are used with force feedback steering wheels.

Answer 2

In general, an electric machine translates mechanical energy into electrical energy (or vice versa). If the process is from mechanical to electrical, the machine is a generator. If it is from electrical to mechanical, it's a motor.

For the machine to accomplish this task, there has to be two magnetic fields; one is in the stationary portion of the machine and the other is on the rotating portion. The magnetic field is generated either by an electromagnet (current passed through a winding, which develops a magnetic field at right angles to the current and is also at right angles to rotation), or the magnet is 'permanent' ... which means it is intrinsically strong, and not requiring an external energy input.

A generator supplies current from its stationary (stator) windings to the load bus connection. The rotor is driven by an external mechanical source, turning the magnets of its field and inducing the current in the stator winding. If the rotor magnets are electromagnets, they must be receiving power from somewhere. And, since they are in motion and the source is stationary, there must be a mechanical interface somewhere. There are two means of supplying this power - either through a brush/slipring interface (the "brush type" connection), or through electronics and/or auxialliary windings mounted on the rotor whose output is fed to the main rotor windings (the "brushless" connection).

PMG stands for Permanent Magnet Generator; in this case, the rotor magnets are of highly magnetized ferrous materials that hold a very strong magentic field, without requiring additional energy. This type of machine does not require either a brush-type or a brushless excitation - the magnets do not need to be excited, as they are not electromagnets.

I'm not sure how to answer you on torque improvement for a DC machine; it has the best torque profile of any machine out there. It operates comfortably in both a constant torque range (usually from standstill to a base speed that corresponds to rated armature voltage and fixed main field current), and in a constant power range (where the armature voltage is fixed at rated conditions and the main field strength is weakened to allow the machine to increase rotational speed).

If you have a better way of explaining your question, email me and I'll see what I can do for an answer.

Answer 3

This Site Might Help You.

RE:
ac brushless generator?
anybody could give me some answers...
what is the difference between ac brushless generator and non-brushless generator?? how about PMG generator??
how to improve torque in dc motor??
please anybody..??

Answer 4

which windings are available on ac generator stator
how do u come up with a neutral cable during rewinding

Answer 5

We have a videos that show you each and how to test them. Check it out on GeneratorGuru.com and click the "Repair advice videos" tab.

Hope this Helps!

Answer 6

residual magnetism