ATV310 Frequency fluctuation happening

[firdaus.alam]

Frequency fluctuation of @ATV310 drive – If I set 25 /30 Hz set point – output frequency is okay from drive and if I set above 30Hz, it give fluctuation in drive output frequency and it varies from setpoint value to maximum frequency. I has also been noted that many times it draws much higher current for same motor and Main voltage (from DC bus) (Modbus Register Address 16#0C87 = 03207) varies a lot. 

Please advise Solution for this - it's newly purchased VFD - 2 nos. and both are having this problem

Operation is 460Volts, 60 Hz, Location -KSA. 

[firdaus.alam]

The Device Status shows is (Obr)

[MatthewM]

I am not a drive expert, but will offer some things to consider.

Start by checking that your ramp settings are sensible.

It looks like your drive could be hunting the output frequency to try and control speed.  What motor control mode is it using?  My guess is it is uuC [SVC V].  Try using Std [Standard] V/F, or uF9 [V/F Quad] with an auto-tune.  I have been told by some experts that auto-tune should not be used, and yet in some circumstances this was the only way to make some loads settle down (I have not needed this on a pump before, though).

Obr is over-braking, indicating it is ramping down faster than the drive can dissipate heat.  This is probably a symptom of the output hunting rather than inertia or fluid flow causing it to be motored.

[MatthewM]

Opps sorry I was referencing ATV320.  ATV310 has different interface.  Check the Motor Control Type at menu 309.  Auto-tuning is under 318.

[firdaus.alam]

Hi Matthew,

Thanks for your guidance.

- 308 - is Maximum Frequency Set which I set 65 Hz whereas 301 (Standard Motor Frequency) I have set for 60 Hz)  - ---- Could this be a Problem?

- 318 is Auto Tuning which I have left as Factory Setting "00" which means "NO" ... Do I need to change this? Could this be the reason of this Frequency hunting?

[MatthewM]

308 and 301 should be fine.

I would be more interested in what 309 is set to.

[BJacqz]

A general comment on drive comissionning, we always advise to enter the motor name plate (with all information such as power, speed, current, ...) and after doing this, perform a motor autotune. This will allow the drive to "know" perfectly the motor. On you case, the OBr is due to motor unstability as it "brakes" when the frequency goes down. You could alos check that speed reference is stable (just to see if it is  a "drive issue", or if this is a "reference issue"). 

[firdaus.alam]

Thanks for your response, please provide the commissioning document link and in detail procedure for Auto Tuning please if possible.

[firdaus.alam]

Hi Mathew,

309 is set to 03 (Standard: 2 point V/F control without internal speed loop).

[BJacqz]

Here you are the user's manual on ATV310.

[MatthewM]

Hmm.  Not behaviour I would expect for 2pt V/F.

As per BJacqz reply, check all nameplate settings are correct, and then perform an auto-tune.  The procedure is described in the manual under 318 "Auto-tuning".

Check that the ramp settings are sensible.  I would suggest it should be 5s or more.

[firdaus.alam]

Motor name plate details input correctly, Auto Tuning done and then started the Motor - Pump.

It's doing lot of noise - the pump draws 11 Amps with DOL panel and this VFD causing same pump to draw 18-22 Amps and lot of noise.  

Please refer the attached video, please read pump KW in HMI with 1 place decimal (160KW = 16.0KW)

[firdaus.alam]

https://www.youtube.com/watch?v=tcRUbYMauPY  - Auto Tuning

https://www.youtube.com/watch?v=koTVM9bR29I  - Motor Parameter Setting

https://www.youtube.com/shorts/tfPwOWFrYiI - Drive Status 

Please review these and advise what's causing motor to make lot of noise and draw high Amps (17-22 Amps) whereas same motor on DOL starter is drawing 10-11 Amps.

[BJacqz]

Hello,

Based on our remarks we can see that motor parameters entered and Autotune done is not satisfactory. 

According to your movie, I see 307 = 3400, is it the nominal motor speed ? I have seen 302 = 7.5 is it the correct motor power ? Then 314 ? 

The next topic to check is the vector control values (setting 320), you can try to change in order to underflux  the motor (decreasing the voltage value of the curve, see on p 57 of manual I gave you). Did you check the motor speed at lower frequencies just to see if the motor is running correctly at lower speed?

On a general poitn of view, I would sayt that if motor current is much higher than normal, it means the ration voltage frequency is not good, this is the way I suggest you to investigate. 

Hope it helps