# Wiring ESC to Volvo electro hydrulic power steering pump



## brian_ (Feb 7, 2017)

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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## timiacobucci (Jun 20, 2020)

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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## turboesp84 (Oct 25, 2020)

i Believe you will need a stepper motor driver to power it up.


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## brian_ (Feb 7, 2017)

Apparently I didn't look very closely at the motor when this thread was new...


turboesp84 said:


> 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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## turboesp84 (Oct 25, 2020)

i have a astra power steering pump that has the same configuration, i believe its called a unipolar motor.


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## brian_ (Feb 7, 2017)

turboesp84 said:


> i have a astra power steering pump that has the same configuration, i believe its called a unipolar motor.


Unipolar and bipolar are the two general types of stepping motors.


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## turboesp84 (Oct 25, 2020)

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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