Notifications
Clear all
Topic starter
31/01/2013 12:55 pm
I really need some help guys. I have a Mid-American controller with a baldor sweo drive. i'm the second guy on the job. i was sent over to pull the drive and send it off for repair. i got it back and put it in. the parameters were corrupted so another tech came over and helped me put all the parameters back in it. we still couldn't get the car to run. he was pretty confident that something was wrong with the encoder. we couldn't get the exact encoder right away so i put on one that was a spare from a job with a similar controller. the old one was a 1040 pulse count, the new one was a 2048 pulse count. i changed to parameter in the drive to match. the car ran after i put the new encoder on, but it ran backwards. up for down, down for up. i'm picking the correct direction relays but the motor turns the wrong way. i changed the parameter for feedback align which is supposed to change the direction of the encoder electrically, but that did not work, the car tries to run in the right direction but it faults out with a following error. i tried to change my a and a not and b and b not, that didn't work either. the motor is a 260v DC motor. i'm new to maintenance(just moved over from construction a couple months ago) so forgive me cause i'm not really sure what kind of voltages i should have coming out of the drive. the only thing i haven't done on the drive was the autotune tests because the book said some needed to be done with the load un-coupled from the motor. the motor also makes a terrible growling noise when it does run. i'm hoping there is a brother out there that can give me some sort of direction to go in. thanks in advance for your help.
31/01/2013 11:19 pm
It's been a long time since I've seen one but I think instead of changing both A and B channel polarities you just need to change the B channel. I'm not dead-sure but that comes to mind for some reason.
01/02/2013 6:37 am
if I am not mistaken, there should be a perameter in the drive switching direction
01/02/2013 8:57 am
Maybe a stupid question, but have you tried swaping your + and - to the motor armature? Then run the car on inspection and see if it runs in the right direction... if not, then swap A and A-...
01/02/2013 9:12 am
I think any of those could work but alot of it is software dependant. I may be wrong but I have had that on different occasions. The best thing to do is to call either manufacturer. The drive or the controller and talk to them. Some drive only come capable of running at a specific encoder pulse.
Topic starter
01/02/2013 11:48 am
thanks for the replies. i haven't tried swapping my motor armature leads or the encoder channels one at a time. i was supposed to go back today with another mechanic, but he got held up on an escalator repair. the mechanic that responded to the original callback was sent over there today by our superintendent. don't know if he got it running, but i will advise when i find out.
01/02/2013 11:55 am
If you happen to be single phased would that produce a growling noise.
01/02/2013 10:33 pm
I know on a Hollister Whitney machine a bad encoder will make it sound like there is gravel in the motor.
01/02/2013 10:46 pm
B+/B- is the channel to switch for direction change.
Topic starter
06/02/2013 10:38 am
car was put back into service today. turns out there was nothing wrong with the original encoder. there was a wire left off of an SCR that was causing it to make the noise.