VFD Fault but runs DOL 1

[powersoff]

VFD Powerflex 4 22A-D6P0N104 Fault code 6.

Motor 2 HP runs across the line when bypassing VFD(because of fault)approximately 1.7amps all 3 phases even when motor is loaded.

VFD can start motor unloaded(empty conveyor). But after starting conveyor fills with product amperage climbs up +11 amps and VFD faults.
Across the line today the motor ran for 8 hours it will not run for 2 minutes with VFD.
The Start and Stop are from keypad and speed control is adjusted via keypad.
Any ideas.

 

[fab1961]

Pardon me if I say something obvious - don't know the Allen Bradley model, but it maybe a parameter problem:
- acceleration time too short
- voltage boost value wrong
or the motor is connected in low voltage

 

[jraef]

Most likely you have the motor parameters set incorrectly on the VFD. I'd look at the V/Hz settings, it appears to me as though you are starving the motor for torque, i.e the VFD is set up for less than full voltage (i.e. 230V or 380V) max output at full speed on a motor that needs 480V, something like that.

(If the motor were connected incorrectly, the problem would follow the DOL bypass)

"If I had eight hours to chop down a tree, I'd spend six sharpening my axe." -- Abraham Lincoln
For the best use of Eng-Tips, please click here -> faq731-376

 

[powersoff]

Jraef I think you are right on with the motor starving for torque.
Incoming voltage is 497 all 3 phases.

I have tried different accel times and they all will start conveyor unloaded, but as soon as product on belt within minutes F6 fault.

In the next few days I should be able to look into VFD settings further. Motor is still running across the line and can't shut off now.

 

[jraef]

I just looked at a manual.

Check A088, which sets the maximum output voltage. It must be set to the motor nameplate voltage, i.e. 460V. If it is anything lower, you are under-exciting the motor windings and losing torque at the square of the voltage reduction. So for example if that was inadvertently set at 380V and you have a 460V motor, your motor is getting 83% voltage at any point in the speed profile, so it is only creating 68% of the available torque and stalling.

Check A089, which sets the Current Limit setting. It should be left at the factory default of 150%, unless you have some special reason otherwise. If that is set too low, the VFD will not allow enough current to get to the motor under load.

Also check P031 which is the motor rated volts. I'm not sure how that might affect other things, but it too should be set to match A088 (not sure why they need two separate settings, but they have them, so make sure they match).

"If I had eight hours to chop down a tree, I'd spend six sharpening my axe." -- Abraham Lincoln
For the best use of Eng-Tips, please click here -> faq731-376

 

[jde777]

Along with Jraef's suggestions to insure correct param settings you should also check the following.


The firmware design uses parameter A082 for bus regulation mode.
Varying line conditions or motor regeneration can raise the bus voltage high enough to simulate a stalled motor condition and generate the error.

Verify that the motor is running at a constant speed when the F6 error occurs

Change parameter A082 [DB Resistor Set] to a "NON-Zero" value.
This will take the drive out of the Bus Regulation mode and clear the fault

 

[powersoff]

Thanks for the replies.
I will compare setttings in VFD to suggestions and implement soon.

Has anyone ever had to setA097(Compensation) to something other then Electrical (current setting)?
My options are.
0 “Disabled”
1 “Electrical”
2 “Mechanical”
3 “Both"

 

[jde777]

I never have had to change that.

 

[Compositepro]

Could it be that the conveyor simply becomes overloaded (too much material on it) if you operate it at less than full speed?

 

[jraef]

Remember, it runs fine DOL, it only draws high current when on the VFD.

"If I had eight hours to chop down a tree, I'd spend six sharpening my axe." -- Abraham Lincoln
For the best use of Eng-Tips, please click here -> faq731-376

 

[Compositepro]

My point is that with DOL start it must run at full speed. The conveyor can only run at reduced speed on the VFD. How is the conveyor fed? It is possible for the conveyor to be fed through some restriction so that the feedrate is not dependent on the conveyor speed. When the conveyor stops material piles-up until the feed restriction is plugged and flow stops. A conveyor can handle a pile in one spot but cannot handle an entire belt that is overloaded.

Many conveyors are designed to run at constant speed with feed rate control by opening a slidegate. If someone converted it to speed control, then the feeder design may also need to change. Nothing the OP has said so far has ruled this out.

 

[jraef]

Ah, very good point.

"If I had eight hours to chop down a tree, I'd spend six sharpening my axe." -- Abraham Lincoln
For the best use of Eng-Tips, please click here -> faq731-376

 

[ozmosis]

I would have thought the first question should be:
Has it ever run with the PF4? If yes: what has changed in the process?
If no, then the PF4 needs commissioning correctly as per previous replies suggest and, as Compositpro indicates, the process design needs to be altered to accommodate variable speed.

 

[powersoff]

JDE777
The only parameter I changed was A082.
VFD runs with 1.7amps per phase . VFD has been running for over 72 hours with no fault. Everything is right with the world.
Based on the manual I don't know how you figured this out.
Thanks