Terry Woods
Member
- Join Date
- Apr 2002
- Posts
- 3,170
We had a recent post about a 3-Phase Motor that reversed direction, apparently, on it's own. It wasn't connected to a drive.
Now, I had a situation today that was kinda similar, but it does have a drive. I only post this to show that it is possible (Murphy?).
I have a drive that is configured to run in Forward ONLY at one of two constant speeds. The speed is selected by a selector switch. The drive goes FAST, or SLOW, or STOP.
The drive drives a motor to an auger. Sometimes the auger is over-loaded. The drive has always tried to maintain speed until it tripped out on over-current caused by excessive material loading. It has operated as expected for about a year.
Today, I saw the auger get over-loaded with wet material (it is supposed to be dry). The drive slowed down from 1200-RPM to 0-RPM without tripping....
AND THEN IT REVERSED DIRECTION
and ran in reverse at 200-RPM for about 5-Seconds then stopped and tried to go FORWARD AGAIN at 1200-RPM 'til it slowed down to 0-RPM and so on.
It could be an interesting "feature" in some applications, but could be disasterous in others!
Just wanted to indicate that weird stuff can happen with drives.
Now, I had a situation today that was kinda similar, but it does have a drive. I only post this to show that it is possible (Murphy?).
I have a drive that is configured to run in Forward ONLY at one of two constant speeds. The speed is selected by a selector switch. The drive goes FAST, or SLOW, or STOP.
The drive drives a motor to an auger. Sometimes the auger is over-loaded. The drive has always tried to maintain speed until it tripped out on over-current caused by excessive material loading. It has operated as expected for about a year.
Today, I saw the auger get over-loaded with wet material (it is supposed to be dry). The drive slowed down from 1200-RPM to 0-RPM without tripping....
AND THEN IT REVERSED DIRECTION
and ran in reverse at 200-RPM for about 5-Seconds then stopped and tried to go FORWARD AGAIN at 1200-RPM 'til it slowed down to 0-RPM and so on.
It could be an interesting "feature" in some applications, but could be disasterous in others!
Just wanted to indicate that weird stuff can happen with drives.