AB PF525 strange behaviour

alexbeatle

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Hello,

I have several plastic-sleeved roller conveyors in series, all driven by the AB PF525's. Most of the conveyors are straight, except for the most downstream - declined. They run rubber material back-to-back which have some spring-back/bounce when the motors go turn on\off.

I keep seeing the following faults sporadically:
-F5 - Overvoltage
-F4 - Undervoltage
-F73 - EN Comm Loss (drives are Ethernet connected to PLC5000 through a switch)

Due to the spring back of material, the stop-mode=coast,CF. No break resistors. Accel Time=5s.

I enabled the FlyStart P545 with the 65% current match for the P546, but that hasn't made a difference.

My theory is I get F5:
-spring-back generates back EMF
-start command is sent when the material is in the process of the spring-back

Motor: 1HP 460VAC
VFD: AB525 25B-D2P3N104 - 1HP

Any suggestions?

2019-02-19_9-38-25.png
 
Last edited:
What are you accel and decel times. These parameters set to low, trying to start and stop a heavy load to quickly will absolutely cause these faults.

As for Ethernet loss..... folks will likely ask more questions about this. perhaps these faults are NOT related

Post your accel and decel times!
 
You did post them.... opss :oops:

Quick thought.... were you able to successfully autotune the drives with these motors?
 
Last edited:
PLC Pie Guy said:
What are you accel and decel times. These parameters set to low, trying to start and stop a heavy load to quickly will absolutely cause these faults.

As for Ethernet loss..... folks will likely ask more questions about this. perhaps these faults are NOT related

Post your accel and decel times!
Click to expand...

Accel=5s
Deccel = 2s, but the stop mode = coast, CF, so it does not matter.
 
alexbeatle said:
Accel=5s
Deccel = 2s, but the stop mode = coast, CF, so it does not matter.
Click to expand...
Yes it does, the Decel rate is still pertinent to a change in speed. Stop mode is only applicable to a Stop command.


alexbeatle said:
Did not auto-tune, just entered the parameters as per the nameplates.
Click to expand...
You should always do an autotune now, even if you are not using SVC or FVC. The newest generation of VFDs (such as the 520s) are switching at much much faster rates and the drive needs to know the motor equivalent circuit to avoid some capacitance issues.


Also check the setting of A550, DC Bus Regulation. The factory default is for it to be Enabled and that helps to avoid this issue, but there are reasons to disable it, so someone may have done that. If so, find out who did it and why, then determine if that was valid and if it can be turned back on. Some people disable it just because they don't know what it does.
 
jraef said:
Yes it does, the Decel rate is still pertinent to a change in speed. Stop mode is only applicable to a Stop command.
Click to expand...

Isn't that the difference between the Ramp and Coast. Ramp will look at the decel time, while Coast will just drop the power to the motor and let it stop as it may?



jraef said:
You should always do an autotune now, even if you are not using SVC or FVC. The newest generation of VFDs (such as the 520s) are switching at much much faster rates and the drive needs to know the motor equivalent circuit to avoid some capacitance issues.
Click to expand...
Cannot rotate tune anymore as the motor is already coupled to the conveyor


jraef said:
Also check the setting of A550, DC Bus Regulation. The factory default is for it to be Enabled and that helps to avoid this issue, but there are reasons to disable it, so someone may have done that. If so, find out who did it and why, then determine if that was valid and if it can be turned back on. Some people disable it just because they don't know what it does.
Click to expand...

A550, DC Bus Regulation is Enabled.
 
Last edited:
I did some work up there a while back and t is my understanding that the standard line voltage is 600 v not the 480 v we use down here. you stated the motor in a 480 v while you can use a 480 v motor on a 600 v VFD
I would first make sure that the VFD is rated for the local line voltage you may get away with using a 480 v VFD on a 600 v line it will be prone to overvoltage faults. if you are having trouble with overvoltage faults I would install a buss loader resistor (breaking resistor). under voltage would mean that the line voltage is sagging down at time of peak load. I would look at the line voltage and see just what is coming in to the system. your acc and dec rated have on effect on the loading change on the conveyor they are only in effect when you start, stop or change the speed reference.
the VFD may be undersized for the application.
 
GaryS said:
I did some work up there a while back and t is my understanding that the standard line voltage is 600 v not the 480 v we use down here. you stated the motor in a 480 v while you can use a 480 v motor on a 600 v VFD
I would first make sure that the VFD is rated for the local line voltage you may get away with using a 480 v VFD on a 600 v line it will be prone to overvoltage faults. if you are having trouble with overvoltage faults I would install a buss loader resistor (breaking resistor). under voltage would mean that the line voltage is sagging down at time of peak load. I would look at the line voltage and see just what is coming in to the system. your acc and dec rated have on effect on the loading change on the conveyor they are only in effect when you start, stop or change the speed reference.
the VFD may be undersized for the application.
Click to expand...

Line voltage is 480VAC.
The motors start and stop often. I'd say with 50% duty cycle, that's why accel decel could be in effect.
 
alexbeatle said:
Isn't that the difference between the Ramp and Coast. Ramp will look at the decel time, while Coast will just drop the power to the motor and let it stop as it may?




Cannot rotate tune anymore as the motor is already coupled to the conveyor




A550, DC Bus Regulation is Enabled.
Click to expand...


You can still do an autotune. Select to "Static" tune the motor. It will not turn while tuning.
 
GaryS said:
I did some work up there a while back and t is my understanding that the standard line voltage is 600 v not the 480 v we use down here. you stated the motor in a 480 v while you can use a 480 v motor on a 600 v VFD
I would first make sure that the VFD is rated for the local line voltage you may get away with using a 480 v VFD on a 600 v line it will be prone to overvoltage faults. if you are having trouble with overvoltage faults I would install a buss loader resistor (breaking resistor). under voltage would mean that the line voltage is sagging down at time of peak load. I would look at the line voltage and see just what is coming in to the system. your acc and dec rated have on effect on the loading change on the conveyor they are only in effect when you start, stop or change the speed reference.
the VFD may be undersized for the application.
Click to expand...

I use the 600VAC supply commonly to run 480 motors on 600 VAC drives in our plant. Its only an issue if the motors are not good quality. Usually the type I see come in on new ventilation equipment, or a pallet load of old auction find motors. Normally, If I can autotune it, it will run without issue. Sometimes they don't want to successfully tune but still run. These are the ones that give me the odd faults and will die first. Replace it with quality drive rated motor, autotune and forget about it.

The 525s I order are specified to run on line voltage of 600 to 400 (or something lower like that)

Also, always doing a factory reset on the drive before doing anything else will do a world of good. Iv seen them come from the factory with parameters other than default!
 
PLC Pie Guy said:
I use the 600VAC supply commonly to run 480 motors on 600 VAC drives in our plant. Its only an issue if the motors are not good quality. Usually the type I see come in on new ventilation equipment, or a pallet load of old auction find motors. Normally, If I can autotune it, it will run without issue. Sometimes they don't want to successfully tune but still run. These are the ones that give me the odd faults and will die first. Replace it with quality drive rated motor, autotune and forget about it.

The 525s I order are specified to run on line voltage of 600 to 400 (or something lower like that)

Also, always doing a factory reset on the drive before doing anything else will do a world of good. Iv seen them come from the factory with parameters other than default!
Click to expand...


These are my motors - VEM3546
 
It is inverter rated.


Whats your normal /average output current when it is at speed?? Conveyor loaded!

Chances are, if this is happening over several similar applications, then it could be a common supply issue or under sizing of the drive.

How many specific applications are we talking about here? Are they all faulting F4 and F5? Are they happening simultaneously or one by one.
 
PLC Pie Guy said:
It is inverter rated.


Whats your normal /average output current when it is at speed?? Conveyor loaded!

Chances are, if this is happening over several similar applications, then it could be a common supply issue or under sizing of the drive.

How many specific applications are we talking about here? Are they all faulting F4 and F5? Are they happening simultaneously or one by one.
Click to expand...

Iavg=1.03A

All faulting F4 and F5, but very rarely simultaneously. Some are more often then the others.
 
Last edited:
It looks to me like that the drive is overloaded
Extend both the Accel and Decel time will help
there may be a parameter in the drive to limit the motor current during the acceleration time. this will automatically extend the accel time install as breaking resister will help with the overvoltage fault.
Up sizing the vfd will help with both
 

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