Aligning axis encoder on '94 VF-1

[GITRDUN]

We had to remove a motor and encoder from a '94 VF-1 due to severe carbon tracking causing a short. Cleaned out the motor and everything ohms out good now. But after putting it all back together the axis will run away the instant you give it a movement command and will imediately alarm out. We can connect a battery charger to the motor leads and the motor will run smooth. With the encoder uncoupled from the motor you can move it by hand and it is tracking the movements until it alarms from excess movement. So i know the motor is good, i know the encoder is working. But for some reason when its all put together it aint happeinin.

I recall a machine technician having to scope an encoder and motor to get them realigned after removing an encoder one time. Is that what our problem is here? We have the motor outside of the machine right now and connected so i can test anything we need to. There is one extra set of wires going into this motor case which i dont know what it is so im assuming its some sort of alignment indicator or something.

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[Al_The_Man]

. i know the encoder is working. But for some reason when its all put together it aint happeinin.

How did you confirm the encoder is working?
I assume this is the DC brushed motor version? If so there should be no encoder re-alignment?
The extra set of wires could be a Tach?
On many systems, the display shows anticipated position, not the actual position, some like Fagor have the option by parameter to set either case.
If your machine is the former, then you cannot check the encoder this way.
I have done it by disconnecting the motor power leads, and use a H.W. to increment a distance lower than the following error, then turn the motor by hand the same distance represented by the ball screw etc, if the H.W. is incremented and the manual turns to keep up with the anticipated display are done, if the encoder is OK, there will be no following error.
Sounds a bit complicated but it works.
Al.

[GITRDUN]

The Haas tech just left. We put a new encoder on it and it still has the same problem. He thinks the problem is in the cable. I am going to switch cables with Z and Y and see what happens. The extra set of wires in the motor are for a heat sensor. If the cable doesnt solve it then i guess its time for a new motor.

[haastec]

The Haas tech just left. We put a new encoder on it and it still has the same problem. He thinks the problem is in the cable. I am going to switch cables with Z and Y and see what happens. The extra set of wires in the motor are for a heat sensor. If the cable doesnt solve it then i guess its time for a new motor.

Curious to know why the Haas tech didn't stay and troubleshoot since he was already there.

[GITRDUN]

I think he troubleshooted as much as he could. He nor i can tell if the motor is really bad. Ill post what i find out.

[GITRDUN]

Bought a new motor from Haas and it runs like a champ. Back in business.

[haastec]

Thanks for the update!

Glad you are back up and running.

[Ron Thompson]

I realize this is an old post. Did the new motor include a new encoder?