Help!!Replacement brushed DC servo motor rotates in the wrong direction...

[NASTYZEN]

Hello all,
Mighty Comet Mill with Dynapath Delta 40-50-60 controller.
Got a replacement servo from eBay. The darn thing rotates the wrong way. I tried swapping the Pos and Neg wires but it just runs away.. Changed them back then tried swapping out the encoder to no good.
Anyone have a wiring diagram for the servos and encoders? I think I may have to swap wires at the encoder.

 

[atex57]

If it all acts OK except direction then switch power leads and encoder leads. Possible complication if the encoder is a differential type.
On edit, check if the controller has an option or parameter to reverse direction.
Ed.

 

[NASTYZEN]

If it all acts OK except direction then switch power leads and encoder leads. Possible complication if the encoder is a differential type.
On edit, check if the controller has an option or parameter to reverse direction.
Ed.

I can't find parameters for this unfortunately. Option B is to change encoder leads but I don't have the schematic. 9 wires on the encoder...
Thanks

 

[Ox]

Since it didn't run away the first time, but went the wrong direction, I would say that you need to switch the DC warrs around, and then ALSO switch the encoder warrs.

Take a pic first! (for ref)


--------------------

Think Snow Eh!
Ox

 

[madmachinst]

maybe your driver is bad?

 

[dalmatiangirl61]

IIRC on a DC starter motor to change rotation you have to change the leads on the brushes. Guessing same would apply to this motor.

 

[Vancbiker]

IIRC on a DC starter motor to change rotation you have to change the leads on the brushes. Guessing same would apply to this motor.

Yes, on some starter motors but not all. A series wound starter will rotate the same direction regardless of input polarity. Servos are permanent magnet motors so switching polarity will reverse but you also have to reverse the A and B channel encoder phases and if used (possibly since the OP says he has 9 wires), the inverse A and B channel encoder phases. If you don’t do that the servo will run away. If the motor has a tachogenerator it needs to be reversed too.

 

[atex57]

If you can get a picture of the encoder label and hookup we may be able to help on the rewire, Vancbiker has a good suggestion on the tach if one is being used.

Ed.

 

[Vancbiker]

On looking closer at the pic the OP posted, the motor has a tach. Not reversing its polarity while reversing motor polarity is a guaranteed runaway. The encoder may not need to be reversed if the Dynapath does not check encoder phasing to determine motor rotation. I long ago sold my Dynapath integrators manual so no reference material to check.

 

[Larry Dickman]

reverse the motor wires, but you also need to reverse the tach wires

 

[RJT]

Just activate mirror image for that axis, problem solved!

 

[NASTYZEN]

Problem solved gentlemen. I simply had to move all the wires on the back of the plug to match the ones on the bad drive. Duh Now works fine and homes. I'm hoping to make some chips tomorrow.
Btw mirror image didn't work.
Thank you all for your input!

 

[Ox]

Ah ... you're right....

Mirror likely would have worked down the road, but Shirley not when HOMING.


----------------

Think Snow Eh!
Ox

 

[madmachinst]

Ah ... you're right....

Mirror likely would have worked down the road, but Shirley not when HOMING.


----------------

Think Snow Eh!
Ox

interesting explain why. Mirror only works on jogging and G code commanded moves? If so why?