Connect High-Power Load to Low-Power Circuit?

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I have a BLDC motor (brushless DC) that my dad got at his work. He said that when the gear heads wear out, they replace the entire, still perfectly fine motor. Why? Who knows. Anyways, this motor had eight wires coming out. The smaller of the eight go to hall sensors (Vcc, Vdd, Sensor A, B, and C). The other three wires are to the coils and are colored red, green, and black. I found a datasheet online [here.

I measured the current a 12V supply passed through one of the coils and it showed ~10A. Keep in mind the motor was not turning during this reading. I plan on connecting the motor to a driver with no sensor feedback as I need the motor to turn slowly for my planned project. According to my research, this is called a six-step trapezoidal commutation.

I found an image that shows the basics of what the connections to the motor should do to turn the motor:

http://www.digikey.com/Web%20Export/tec … -fig1a.jpg

That image can be found on this page: http://www.digikey.com/en/articles/tech … y-function

At the moment, knowing the rotor position is unnecessary, else I would use the hall sensors. But to my question. I plan on using my Arduino Uno to time the sequences. But the Uno will only push a few mA at 5V, not 10A at 12V. I thought about using relays, but I’d need six of them. And then I thought about logic gates, but they only push a few mA. Then I thought about transistors and/or MOSFETs. But my latest experience with those says I’ll still not be able to do it [well].

So how would you do this?](http://www.peromatic.ch/f/produits/moog/moteur_sans_balais/bn34.pdf)

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Have a look at this http://ww1.microchip.com/downloads/en/a … 00857a.pdf from Microchip. Towards the end is a schematic which shows the use of a Power MOSFET. You could adapt this to an Arduino quite readily.

Also, here is a video which describes the basics of brushless DC motors

http://www.youtube.com/watch?v=ZAY5JInyHXY

Jake

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In addition to the App Note jake linked to Microchip has these App Notes on sensorless BLDC motors control.

AN885, AN899, AN970, AN1305. Then there is AN898 on “Determining MOSFET Drive Needs” which is a good read on using MOSFETs.

An Arduino Uno is perfect for controlling a BLDC motor and many of the commercial ESCs for RC airplane BLDC motors use an ATmega 168. With some web searches you will find info on doing a BLDC motor controller with an Arduino.