[MattBrauman]

We have a Maxim 500 with Acramatic 950 control that was rumbling when you moved the Z axis. It started out just doing it when it was cold and quit when the machine warmed up. After a few months this became worse and today it wouldnt hardly move at all with out the rumbling. It kind of sounds like the servo is fighting itself to hold location or something. We had a spare servo motor, so we pulled the first out and put in the new one but now i have a Z axis + overtravel and i can get it to move. I physically rotated the ballscrew away from the overtravel area and worked the overtravel limit switch, but no luck. If I hold down the system start button and touch the overtravel release button it shows Powerfeed Z +, but pushing those button gains nothing. Thanks.

[mike_Kilroy]

sounds like orignal motor had bad bearings. sounds like when you replaced it you knocked wires off LS - double check the limit switch wires. get someone to watch LS inputs on control when you activate them....

[MattBrauman]

There was a cable that got pulled off. Plugged back in but now when we start the machine it will rapid -Z direction until it overtravels. When changing a servo motor on a Cincinnati is there anything special you have to do? I'm not sure if the new drive is any good, it is just a spare that was left.

[mike_Kilroy]

When changing a servo motor on a Cincinnati is there anything special you have to do?

Maybe.

No clue how to answer without you at least giving us the drive part number; there were many different ones used.

[meckardt55]

If the wires are not the same on the new motor as the old motor the slide will run away. You need to check the motor wires and ohm them out per the print. The slide should only travel less then 1 inch uncontrolled and a servo fault or open loop or excess error alert should come up on the control. Are you getting any alerts???? mike cncmachineservices (dot) com

[MattBrauman]

It turned out to be the drive, we swapped out the 2 Z axis boards from another machine and all is well. The servo that ran away was apparenty bad. Thanks for your response.