Question on bldc motor

Hello all,
I am new to motor control. I do have experience with steppers but that’s the extent of my knowledge. I have acquired a BLDC drive out of an old washing machine. I don’t know how much current it needs to draw nor what voltage it runs at. I have seen on line where some people have driven them off of a 12 v supply buts that’s it. Will a ODrive handle this motor?
Any advice will be welcomed.

Wayne Hilliard

Normally anything from a washing machine will need mains voltages, at least to get to its full design speed & power.
But if someone has had it turning on12V that is encouraging. ODrive will probably work, provided it has a good enough position feedback for whatever it is you want to do with it.
Spinning a washing machine drum can be done with Hall sensors or no sensors at all, but turning it into a servo will require a high resolution position sensor.

I would definitely recommend the 56V ODrive for this one though. :+1:

Thanks Tom,
Let me explain my project and maybe that will put some constraints on whats needed.
I am a amateur astronomer as well as telescope maker. I am currently designing a fork mount for a larger telescope IE 14" so total load will probably be around 100 LBS more or less. I have been jealous of the guys with the direct drive mounts they are a lot more versatile as far as what can be tracked as opposed to worm gears etc. So the speed requirement is very low it will track at 1 rev per day. On the other hand the positional requirements are high. I will be using a Renishaw magnetic rotary encoder to provide feedback. So maybe I can get by with a 48 Volt supply and using the Odrive 56 volt driver! That is my direction at the moment unless I get different feedback.
Thanks again!!!

Wayne Hilliard

Nice :+1:
Yeah ODrive should be perfect for this.
Bear in mind that even a 14 bit magnetic encoder will have around 3-4 bits of noise, which is (360*/16384) * 10 = 0.2 degrees error. The integrator in the position controller will average that out a bit, but you can’t expect better than 4 counts in 16384 of position following accuracy - If you need more than that, use a belt drive reducer.

Also, I’m not sure if Renishaw encoders are supported (yet).
MPS MagAlpha MA732 are supported, as well as AMS AS5047p (although I have had some issues with these) plus CUI AMT23x, and some RLS encoders.

In general I would prefer absolute encoders with serial interface over incremental encoders, because it makes calibration easier (only needs doing once, not on every boot-up). And calibration requires mechanically disconnecting the load, so not easy to do on boot up.

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