Fault yaskawa drive

HI EVERYBODY
I have a uncoiler machine with a Yaskawa drive connected to a 3 phase motor. When motor running at full speed then fault OV (over volt) is generated and drive trips. The only way to run the drive is to reduce the speed(speed pot)and system runs ok. Please let me know anything if problem is known to you.
Thanks

You need the booklet that normally comes with the drive if you do not have one I suggest you download it from yaskawa's website. The fault and the correction will be listed in the fault menu. I have only used a couple of yaskawas drives and I think auto tuning usually corrects most faults, if it does not then its normally just a parameter change. Regards Badger.

If the item being turned attempts to turn the drive faster than designed, then there is a dc voltage fed back to the drive and you get the Ov fault, which is the DC bus overvoltage. This also happens a lot when a motor is being ramped down or when attempting to use the drive to "brake" the motor to a stop.

If this happens when the motor is motoring (driving the load), then it is most likely just as Badger says----the speed loop is unstable and needs retuning.

If it happens when the motor is being overhauled by the load, then you have a braking situation and the drive needs to be equipped with adequate braking resistors to dissipate the braking energy.

So, start with the motor to determine which way it is running at the time of fault.

solution is very simple , just change the acceleration and deceleration to longer times

PERSPOLIS said:

HI EVERYBODY
I have a uncoiler machine with a Yaskawa drive connected to a 3 phase motor. When motor running at full speed then fault OV (over volt) is generated and drive trips. The only way to run the drive is to reduce the speed(speed pot)and system runs ok. Please let me know anything if problem is known to you.
Thanks

Click to expand...

As mentioned, things to check.

Is the motor putting energy back into the drive (sudden decrease in load, or the load is accelerating the motor past it's driven speed).

If it is happening on deceleration, then you can try increasing your deceleration time.

Both of these may also be fixed by installing/checking a brake resistor.

Also check the voltage setting on the drive. It should match your incoming voltage. Having a setting of 460 and running at 490V will also cause an overvoltage.

Good Luck.

Thanks a lot for your replies, I will change the parameter values accordingly and I will let you know the results.

adel1961 said:

solution is very simple , just change the acceleration and deceleration to longer times

Click to expand...

Not necessarily.

adel1961 said:

solution is very simple , just change the acceleration and deceleration to longer times

Click to expand...

allscott said:

Not necessarily.

Click to expand...

Yeah, these new high efficiency motors coupled to a pulsating or reciprocal load can also be frustrating. And don't forget power factor correction somewhere else in the plant.

HI EVERYONE
Can somebody explain how DECELERATION is performed by the drive and difference between deceleration and ramp to stop of a three phase motor. Thanks a lot.

Motor speed is determined by the hz so the drive increases and decreases frequency to get the motor to accelerate or decelerate. This is true whether you are changing from one speed to another or when starting or stopping.

You can disable the stopping ramp by selecting "Coast to Stop". In that case, the drive simply stops all output de-energizing the motor so it coasts to a stop with neither positive or negative torque.

With "Ramp to Stop", the drive controls the motor down the decel ramp to zero speed where it then de-energizes. If the load normally coasts to a stop in a shorter time than the decel ramp, the motor will drive the load (positive torque) down the ramp to a controlled stop. If the load normally coasts to a stop in a longer time than the decel ramp, the motor tries to pull the load down the ramp (negative torque) as a brake trying to enforce the decel ramp. The motor becomes a generator under these braking conditions and the regenerated energy flows back to the drive. If the drive has braking capacity, this energy is wasted as heat in resistors or regenerated back into the power supply for reuse elsewhere. Otherwise, the drive faults on High Bus Voltage.

If you can put a meter on your DC bus voltage, or view the bus voltage on your keypad, then you can determine without a doubt that the increase in DC Bus voltage is causing the issue. When you are running a 460 Volt motor, your bus voltage will be around 660 to 680 VDC. When you decelerate too fast, it will increase. The trip point is not adjustable and is at around 710 Volts. I guess where you are you could have a 575 Volt motor, which means that your Bus Voltage is usually around 1000 VDC, and trips around 1030 VDC. This trip point is not adjustable. You can only remove the cause of the voltage increase.

You can also verify that the braking resister unit is wired properly if one exists. That wiring is a little tricky, and the documentation is not so good.

Another thing to consider is your line voltage. If you have a high line voltage, then you have less ability to stop fast. The key here is of course, watch your bus voltage.

If you have an encoder, then check to make sure that it is not slipping on the shaft.

Let us know what you find.

Thanking you all for the replies.The drive comes with dynamic braking, connected to B1 and B2,with three phase motor 575 volt without encoder.
In reference to GPD 515/G5 DRIVE manual page A1-2,looking at the menu three and parameter there are b1-03 (stopping method selection) and b2 (dc injection braking) then questions:
1-what would be the setting when drive is connected to DYNAMIC BRAKING, Should it be factory setting.
2-In regards to DC bus voltage how dc voltage can be observed on keypad I have not found yet this feature looking at the manual unless you know how.
I have recorded most of the menu readings but left it at the factory and will be available in my next post.
As mentioned earlier the OV fault comes when drive working hard in addition I have also checked the voltage selection and jumper connected to 575/600 v .Thanks

http://www.clrwtr.com/Yaskawa-Drives.htm list most industrial AC Drives from Yaskawa.

Hello

Using Yaskawa drives I would like to know what resolved issue.

Was it,
Autotunig
Process turn the drive faster than designed
Parameter change (acceleration, deceleration time)
(Input Voltage, Motor voltage)
High input voltage
A short after drive
If tunning open loop or closed loop vector servo
Did you try to set parameter B3-11 to set OV supression?


Just curosity.



Tom