accidentalengineer
Member
First of all, this isn't an emergency. I'm just playing around with a PowerFlex DC drive and a dc motor on a test setup. Everything works fine, except that the motor's speed does not come close to matching the speed stated on the drive - it is off by 300 rpm throughout its range. I'm running it using armature voltage feedback. A few things:
1. The jumpers for armature voltage feedback 1A1 to A1 and 1A2 to A2 are properly installed.
2. Parameter 414 is set to 3 for armature feedback.
3. When rated armature voltage is applied and full field current is applied the motor runs at base speed. So I believe the motor nameplate information to be correct. And I believe that my hand tachometer is reading correctly.
4. I can "lie" to the drive and make the tached and displayed speed read the same by telling the drive that the rated armature voltage is 150 VDC instead of 240VDC, but then my top end speed is limited because I get into armature overvoltage faults.
There is a provision to adjusted the feedback rpm by a paltry +or - 20 rpm P563), but what I really need is a way to correct the slope and offset of the feedback so that the drive's state speed matches the speed that the motor is actually running.
Does anybody have any ideas out there? Is there a problem with the drive?
1. The jumpers for armature voltage feedback 1A1 to A1 and 1A2 to A2 are properly installed.
2. Parameter 414 is set to 3 for armature feedback.
3. When rated armature voltage is applied and full field current is applied the motor runs at base speed. So I believe the motor nameplate information to be correct. And I believe that my hand tachometer is reading correctly.
4. I can "lie" to the drive and make the tached and displayed speed read the same by telling the drive that the rated armature voltage is 150 VDC instead of 240VDC, but then my top end speed is limited because I get into armature overvoltage faults.
There is a provision to adjusted the feedback rpm by a paltry +or - 20 rpm P563), but what I really need is a way to correct the slope and offset of the feedback so that the drive's state speed matches the speed that the motor is actually running.
Does anybody have any ideas out there? Is there a problem with the drive?
Last edited: