Allen-Bradley 1352 VFD Start time delay

Chris335577 · Jun 29, 2006

I have a AC drive that has a time delay of 17 seconds before the Motors start to hum and the VFD delivers voltage.

Does the drive have a time delay paramater after sending it a start and reference signal.

The Drive is 20 years old.

Jimmie_Ohio · Jun 29, 2006

Try this link:

http://literature.rockwellautomation.com/idc/groups/literature/documents/um/1352-um000_-en-p.pdf

This PDF looks like it's a 20 year old scan! Good luck. This manual is 270 pages.

Chris335577 · Jun 29, 2006

Does any VFD have a time delay after a atart and reference signal is applied?

Thanks,
Chris

rgurin · Jun 29, 2006

What network are you using to communicate with the drive? A 17-second communications delay seems very long, but it's not out of the realm of possibility.

Are there other delays for other machines on this network?

Rick

Chris335577 · Jun 29, 2006

It could be RS-232 network. Whatever the main network that was in use at the time. Also their are two drives and they both have to start at the same time. The 17 seconds is a total for both drives.
The PLC has to communicate with both drives.

Thanks,
Chris

Chris335577 · Jun 30, 2006

The Drive uses a 20 milliamp current loop at 4800 baud with SAMI digital drive communication protocol. It communicates with the PLC by using a Allen-Bradley 3500-NA2 PLC Interface Module.

PLC2/30----------1772 SD2------------3500 NA2--------------1352C

I guess there is a lot of room for communication delay?

rdrast · Jun 30, 2006

Is that a delay from Initial Power On until it can spin a motor? Or is it already powered up, and it takes that long after giving it a reference and a run command?

If the first, the bus capacitors may be going south (if the unit has them), if the second, perhaps it's just an accel setting problem.

Has this always happenned? Or did it just start to happen?

DickDV · Jun 30, 2006

I know essentially nothing about communications of that period but, if the drives are configured with motor Premagnetization you could be seeing the effect of having the Premag period set too long. usually 1 or 2 seconds is more than enough.

Allen-Bradley 1352 VFD Start time delay

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