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Discussion Starter · #1 ·
I have read as much as I can find on electric hydraulic power steering pumps and I have some questions. I got this junkyard pump in nice shape off a volvo. It is a brushless trw unit. I was planning on doing something similar to what Old dsmer had done using an independent esc to control the motor directly. In other uses on drift cars there have been issues with the pumps being unable to keep up with high demand running in default mode. I was hoping to be able to setup a controller to run the pump at full power when needed.

First off my motor and control circuit look very different than the hyundai unit old dsmer was using. I have previously used a VESC to control a bmw pierberg brushless electric water pump but I cannot figure out what the motor circuit is in this volvo unit though or where to connect the vesc leads.

I would imagine it is 3 phase yet there are 4 transistors connecting to the motor wiring. Does anyone have any suggestions as to how to figure out what sort of circuit this is using?

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It looks vaguely familiar, and there's a whole generation of Volvos built on Ford platforms, so is this by any chance the same as the pump in a Ford Focus etc? What model and year of Volvo is it from? I'm sure that Ford pump has been discussed in this forum, although I don't know if there was a good resolution... it could be worth checking, anyway.
 

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Well its got a fomoco label cast into it... I will try and look. You guys are the motor gurus, any good resources on reverse engineering them?
 

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Apparently I didn't look very closely at the motor when this thread was new...
i Believe you will need a stepper motor driver to power it up.
Excellent observation!

The rotor looks like it has seven segments, but that's not an even number so the visible segments must be pairs of permanent magnets, making it a 14-pole rotor. That unusual count - not matching the 4-pole (assuming that it's 3-phase) stator made me think of switched reluctance motors, and one driver design for both switched reluctance motors and stepper motors (called "n+1") would use four switching transistors (and four diodes). It's not switched reluctance (the rotor is shaped right for that, but it likely is a stepper motor driven by a n+1 switcher... I think :)
 

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what switching transistors are you thinking of using? im going to control the one i have with an arduino its going into a petrol engine car, the powersteering is to light so im going to use the gearbox transducer to be speed ref the faster you go the heavier it becomes
 
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