Could I use brushless DC motor as a generator?
Could I use brushless DC motor as a generator?
(OP)
Dear all,
I would like to know if it is possible to use brushless DC motor as a generator.
I would like to know if it is possible to use brushless DC motor as a generator.





RE: Could I use brushless DC motor as a generator?
Quite a few small wind turbines use a permanent magnet generator (or in more proper terms a 3-phase alternator).
RE: Could I use brushless DC motor as a generator?
RE: Could I use brushless DC motor as a generator?
Your outputs won't be sinusoidal, though, so you'll probably choose to rectify and smooth to DC.
(if you choose a PMSM-type instead, you might get some nice sinewaves).
Benta.
RE: Could I use brushless DC motor as a generator?
Although many conventional DC motors will quite happily generate DC when driven, a brushless DC motor does not run on pure DC. When driven it will produce an alternating current and may be referred to as an alternator. It is also correct to call it a generator but it will not be a DC generator and will not produce DC.
Bill
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"Why not the best?"
Jimmy Carter
RE: Could I use brushless DC motor as a generator?
A typical alternator has a coil on the rotor and by varying the current in this coil, the rotor magnetic field is varied. This allows control of the output voltage.
RE: Could I use brushless DC motor as a generator?
Can you generate electrical power cleanly and directly into a grid? Almost surely not. In these permanent-magnet brushless motors, voltage and frequency are not independent; they are almost directly proportional. So it is very difficult to keep it both the proper time-synchronization to the grid (frequency and phase) and the proper voltage levels.
Curt Wilson
Delta Tau Data Systems
RE: Could I use brushless DC motor as a generator?
Are you referring to the rotor in your response as the armature? I thought in DC machines usually the field was what had the permenant magnets and it was the field that established the flux and therefore magnetic field.
RE: Could I use brushless DC motor as a generator?
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Could I use brushless DC motor as a generator?
Curt Wilson
Delta Tau Data Systems
RE: Could I use brushless DC motor as a generator?
If you connect a voltmeter to the power DC leads, do you get voltage out when spinning the motor?
Possibly the protect diodes will feed voltage out. My LG washer turns on when I spin the drum. A 12V computer fan doesn't
RE: Could I use brushless DC motor as a generator?
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If it is broken, fix it. If it isn't broken, I'll soon fix that.
RE: Could I use brushless DC motor as a generator?
All the bike alternators I have seen have a spinning permanent magnet inside a 3 phase winding & 3 phase rectifier. My Guzzi just has a single phase winding. The voltage regulators I am familiar with short out the winding when the battery is up to voltage. I found that a bit puzzling at first but I expect you can only get so much power out of a permenent magnet alternator so shorting out doesn't cause excessive current.
Roy
RE: Could I use brushless DC motor as a generator?
Brushless DC motors and motorcycle alternators are similar in that the rotor is composed of permanent magnets and there are windings on the stator.
There are differences in design compromises and size.
The motorcycle alternator is designed with a high resistance winding so that the voltage may be safely regulated by shunting. The excess power is wasted as heat in the windings. The alternator may be designed so that here is as much induction as possible. The inductive reaction will increase with frequency and aid in limiting the current at high RPMs.
The brushless DC motor will be designed for efficiency. The brushless DC motor may be constructed in much larger sizes that a motorcycle alternator. Using a brushless DC motor as an alternator with shunt regulation may cause the motor to fail at high speeds. Using a motorcycle alternator as a brushless DC motor may result in poor performance and overheating.
Bill
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"Why not the best?"
Jimmy Carter
RE: Could I use brushless DC motor as a generator?
I didn't think so, but it's now apparent to me the term is a big source of confusion.