Powerflex 525 not reaching set speed

bornwild

Member
B
Join Date
May 2010
Location
Riyadh
Posts
429
Hello,
We have a strange behavior on powerflex 525 drive running a blade with v belts attached to the motor .The drive only shows accelerating and does not reach set speed. Current limit is ok. Strange thing is when I only run the drive with out the load it vfd reaches the speed. When we give the blade a gentle push with hand it accelerates and reaches set speed. What could be the reason
 
No this drive is running from before. It says accelerating and doesn't reach the command frequency. I give it a push with hand and it starts
 
Drives_Guy_NS said:
Then I suggest that you do one of two things; switch to SVC and autotune; or add a start boost to your drive in V/Hz.
Click to expand...
Do an Autotune even if you are using V/Hz. All of these Gen 4 IIGBT based drives now need to be tuned to the motor regardless of the operating algorithm.

And when you say "Current Limit is fine", what does that mean? Is it never reaching the Current Limit setting, but also not accelerating? Because how Current Limit functions in a VFD is to OVERRIDE your speed setting in order to keep the current controlled. It would do EXACTLY what you are reporting.

Since you are operating in V/Hz mode, this issue can be exacerbated by improper settings of the "Boost Select", parameter A530. That is REALLY tricky to get exactly right and if load conditions change over time (i.e. things start wearing out), needs periodic adjusting. That's a good reason to change over to SVC by the way...
 
jraef said:
Do an Autotune even if you are using V/Hz. All of these Gen 4 IIGBT based drives now need to be tuned to the motor regardless of the operating algorithm.

And when you say "Current Limit is fine", what does that mean? Is it never reaching the Current Limit setting, but also not accelerating? Because how Current Limit functions in a VFD is to OVERRIDE your speed setting in order to keep the current controlled. It would do EXACTLY what you are reporting.

Since you are operating in V/Hz mode, this issue can be exacerbated by improper settings of the "Boost Select", parameter A530. That is REALLY tricky to get exactly right and if load conditions change over time (i.e. things start wearing out), needs periodic adjusting. That's a good reason to change over to SVC by the way...
Click to expand...



Thank you for the reply.
Drive over load mode is set A495 is set to Both PWM 1st with current limit A484 set to 40.7 . The motor is taking amps of only 22-25 amps.

When i start the drive with set frequency of 58 hz the motor reaches only 6 hz .

I will try to tune the drive and see the results but the yesterday i swapped the power module from other machine and it runs fine with the same parameters and the problem shifted to other machine .Could be faulty power module? but why it works when we give a intial push with hand on the load..
 
Check the motor leads
Phase to Phase resistance and the current on each Phase
with it only running up to 6hz and then will run all the way you if it is nudged.
I would bet if it was nudged I reverse it would accelerate up to full speed in reverse.
The drive may be waiting on the counter EMF from all 3 motor leads to continue up

The drive could be bad as well ne phase not powering the motor lead correctly
 
GaryS said:
Check the motor leads
Phase to Phase resistance and the current on each Phase
with it only running up to 6hz and then will run all the way you if it is nudged.
I would bet if it was nudged I reverse it would accelerate up to full speed in reverse.
The drive may be waiting on the counter EMF from all 3 motor leads to continue up

The drive could be bad as well ne phase not powering the motor lead correctly
Click to expand...


We swapped the power module keeping the control module the same means all the parameters are same.The motor runs with out any issue which rules out any issue with the motor or wiring

strange thing is the old power module still runs once i give it a nudge on the load . So i can not confirm what is the exact problem
 
One of the phases from the bad power module is missing. This is the same action that would happen to a three phase motor with one phase lead disconnected. The motor can be hand started in either direction and the motor will start turning. Since it it is missing the phase it won't run with full torque and, depending on load, may not reach full speed.
 

Similar Topics

M
Changing a PowerFlex 525.
Hi to all. We need to change a bad powerFlex 525 to a new one. How do you save the configuration to install in the new one? Thank you all for...
Replies
5
Views
210
James Mcquade
J
T
Teacher needs some help with Powerflex 525.
Im trying to teach a couple of labs on VFDs at a community college. We have some motor control trainers with P525s and 3 phase motors from...
Replies
0
Views
123
tim_callinan
T
E
Powerflex 525 programming
New to vfds. I put in parameters. IP, but I get ethernet flashing and link solid. What did I do wrong?
Replies
9
Views
446
robertmee
R
R
Powerflex 40p to 525
Are the N files in the 525 the same as the 40p for ethernet? (E-Comm card) I have used 40P with Micrologix 1400 Messaging but don't see the N...
Replies
4
Views
220
roxusa
R
T
Powerflex 525 has a frequency of 2-2.50Hz when being told to stop
Hey all, I am currently working on a depalletizer for a customer and we are doing a hoist upgrade. This is a SLC500 processor and the drives are...
Replies
6
Views
282
Tbone1465
T
Back
Top Bottom