×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

DC Motor Drifting/Speed Issue

DC Motor Drifting/Speed Issue

DC Motor Drifting/Speed Issue

(OP)
I have a 1HP DC Motor driving a fleeter that reverses direction upon command.  I am using a speed reference from another dc drive to control the speed of the fleeter (through discrete adapter board).  Both of these are driven with an older model AB 1395 Drive.  With a 0 speed reference coming into the fleeter drive I am commanding the fleeter motor to be at 0 speed but the motor will drift.  I can remove the speed reference cable at the drive and it will still drift.  I can adjust the offsets in the drive and eliminate the drifting but that causes the motor to run faster in one direction than the other.  All of this just started after replacing the discrete adapter board.  I tried another board - same thing.  Is there anyway this could be a motor issue and not a drive issue?

RE: DC Motor Drifting/Speed Issue

(OP)
We are using a prox to count revolutions on the worm gear that is driven by the fleeter motor.  We are then using a relay to switch polarity to reverse the motor.

RE: DC Motor Drifting/Speed Issue

I have not done a lot of this but it sounds to me like your drive is losing it.  Since disconnection from the other drive still leaves the drift I think your drive is having some component fail.

I don't know how hard it would be, but a test would be to swap the drives.  If the drift follows the drive you have it.

I can think of no mechanism thru which the motor could cause this.  And your prox as described shouldn't be doing it either.

Older drives relied on lots of analog circuitry that can start shifting as the components age.

The fact that it started after the I/O board change is either pure coincidence or you static zapped the drive during the work.  This kind of problem is typical of 'zapped' analog circuitry.

Keith Cress
kcress - http://www.flaminsystems.com

RE: DC Motor Drifting/Speed Issue

We had a AB1395 with similar issues although the feedback was a tach.  Replaced the Control Board and so far have not seen the problem repeat.  Did not reload parameters, swap  E2 chips.  

RE: DC Motor Drifting/Speed Issue

(OP)
Thanks, I will try changing out the main control board.  Maybe the board was zapped during instalation of the discrete board, as itsmoked stated.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources