G120 actual speed fluctuates

Good day,

HW:

• TIA Portal v15.1
  
• CPU 1515F-2 PN 6ES7 515-2FM01-0AB0 v2.6
• SINAMICS PM240P-2 IP20-FSD-A-400V-22kW - 6SL3210-1RE24-5AL0
• SINAMICS G120 CU230P-2 PN - 6SL3243-0BB30-1FA0
• SINAMICS G120 BASIC OPERATOR PANEL - 6SL3255-0AA00-4BA0

I have got 5xG120 fans in the project, I commissioned them all similarly and they are working but one is causing some problems. I set the setpoint to 1500 l/min, the fan ramps up nicely and the actual speed gets to 1500 l/min, the problem is that then the actual speed slightly fluctuates from 1490-1530 every few seconds. Is there anything I can parameter to at least lower the fluctuation because the sound of the fan is bothering the client.

If needed I can provide video of the actual speed vs set point on the operator panel. This is my first time working with G120 I hope you can point me into the right direction.

Thank you!

If you reduce the set point, does it stabalize?

Tractor

Tractor

If you reduce the set point, does it stabalize?

Tractor

 Tried changing SP and it does not stabilise.

Please check below points. (here I presume, set point is constant)

1. Have you optimised/tuned drive?

2. Have you checked current & torque limits? Are those OK?

3. Check if current limit causes speed fluctuation.

4. Check motor power connections for any loosnes at terminal or drive end.

PISCEAN 2010

Please check below points. (here I presume, set point is constant)

1. Have you optimised/tuned drive?

2. Have you checked current & torque limits? Are those OK?

3. Check if current limit causes speed fluctuation.

4. Check motor power connections for any loosnes at terminal or drive end.

 1. I ran measurements again

2. I changed current limit to be the same as rated limit in commision wizzard

3. Didn't check but current did jump from 10 to 30 to 90A when it happened.

4. Motor power connection seemed fine.

It seems that either step 1 or 2 solved my problem for now. I will write back if anything changes.