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How can I find new driver boards for my 5-phase motors? Answered

I will try to summarize the problem:

1. I have a CNC mill sitting in my garage that won't work because the whole control unit including the motor driver boards is shot.
2. I can't buy new driver boards because I don't know what spec to buy
3. I don't know which spec to buy because I am not an expert on 5-phase stepper motors and don't know how to judge / measure / test them to find their spec.

So the CNC mill is of type EMCO F1P (1984), and it looks like this (actual photos of the unit).

The control box that comes with it houses an awesome (for the time) integrated computer based on intel x86 chips to convert G-Code into movement. I had fun digging around inside it and here are some details about that journey.

Unfortunately its from 1984 and in deteriorating shape. After being adamant for years, I have since given up restoring the control, and the current plan is to simply focus on the the machine itself with motors, which luckily is in a much better shape. This means that I will buy new motor driver boards to drive the existing steppers and get a LinuxCNC kind of control to control them.

It turns out that finding a 5-phase step driver was much harder than I first anticipated. It doesn't help that the motors are without a spec. I asked a question on the ee stack site previously for finding the specs for my motor here but I didn't get any meaningful answers.
I also blogged about this with lots of pictures here.

So to sum it all up, any help/advice is welcome on the following:

 + How to measure/test the motors to find their specs and hopefully a matching driver board
 + Which brand of board is good/bad/cheap etc.
 + What to look out for that I would not think of as a beginner

PS: I know I could replace the motors with cheap Chinese 2-pole ones and be on my way, but I really want to do this the right way, and maybe learn something underway!

5 Replies

steveastrouk (author)2017-04-17

If I were you, I'd abandon the old control, and replace it with your Linux solution. I'd replace the steppers with Teknic's BLDC servo drives and be done with it


Yes, it will cost you about $350 per motor - but that INCLUDES the driver and a certain amount of intrinsic brain.

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lennartr2 (author)steveastrouk2017-04-21

Even if it is expensive, I would like to keep the motors. Yes I completely agree that the Clear Path servos are awesome, I already looked into them ,they have some amazing properties! But, there is something about these motors. They have that "back to the future feel. Do you know what I mean? The whole aesthetic of the machine with the cooling fins and hoses and what not. Also the sound. my god, these motors make the best sound in the world! It's like having The terminator in your garage.

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iceng (author)2017-04-17

How many wires are coming from each motor.. I'm trying to discover if it is unipolar or bipolar winding..

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lennartr2 (author)iceng2017-04-21

Hi, sorry for late reply!

There are 10 wires. If you follow the links in the question you will be able to see detailed images of the interior of the motor, as I have taken it apart and photographed it.


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steveastrouk (author)iceng2017-04-18

He's into either expensive off the shelf solutions, or trying to roll his own if he keeps the motors. Oriental do drive boards, but BLDC are the way to go.

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