Brushless Motor phase wires? AC or DC volts?

[sonnetg]

Hello,

I am curious whether my Brushless Geared motor is AC or DC. I am not very familiar with brushless motors, so I am wondering whether the controller feeds AC or DC voltage to the phase wires? The motor does have 3 phase wires and 5 hall wires.

I have a Geared motor, so i can only rotate it one way to generate any electricity. While measuring volts, I seem to be reading AC volts on my multi-meters. When I set my meter to DC volts, I get all sorts of bizarre reading on my multi-meter.

I am a bit baffled. In some places I have read the Brusless motors are fed AC volts, but when I purchased the motor, it was labeled as BLDC (Brushless DC) motor.

Are there two types of Brushless motors (AC/DC)?

Thank you

 

[amberwolf]

It's really just switching DC from your battery to it, but because of the way it works, it switches polarity on each phase, which on your meter results in AC.

So, the answer to your title question is "yes".

 

[sonnetg]

Thanks abmerwolf. Seems like i have a lot to learn all the new motor technology. It seems BLDC motor and Induction Motors are all the rage now. If I understand correctly, both these type of motors accept DC as the power source but use an inteverter to convert to AC current for efficiency and torque. Will do some further research on this. Very interesting stuff for sure..

Here's an interesting video simplifying this rather complex operating...

[youtube]fGPdPKMSpv8[/youtube]

 

[amberwolf]

If I understand correctly, both these type of motors accept DC as the power source but use an inteverter to convert to AC current for efficiency and torque.

Neither of the *motors* accept DC. Just their controllers.

 

[sonnetg]

If I understand correctly, both these type of motors accept DC as the power source but use an inteverter to convert to AC current for efficiency and torque.

Neither of the *motors* accept DC. Just their controllers.

Ah..u r correct.

so is the AC volt through the phase wire to the motor pulse width modulated (PWM)? How exactly is the speed controlled on these motors?

Is there any way to test using a volt meter how much volt the motor is being fed?

 

[amberwolf]

I think you might want to read some of the wiki entries on how motors work (both on ES's wiki and wikipedia), and also the stuff in the sticky index in this subforum.

Otherwise we're just repeating stuff that's already been written.

 

[sonnetg]

Yup. Sounds like a good idea :wink:

Thanks.

 

[amberwolf]

Sure--if you still have questions after that, then this thread would be a good place for them--the Q&A might help other readers later, and might also point to improvements to be made to the articles/etc.