Hi All

I have a g120 x inverter and from installation only parameters have been altered are motor nameplate values

when we connect a motor on startup the motor rocks back and forth for about a second

before staring has any one a suggestion as to what this can be  ?

Regards

Mel

Hello

is the power of the motor and the drive equal? ​​

What machine is the drive used for?

Does the motor start under load? 

What is the length of the motor cable?

Please check the stator resistance

Hi

the inverter power is larger than the motor the machine is a centrifugal pump

but the motor nameplate parameters are entered in the inverter

the cable is about 2 m in length

it doesn't not seem to make any difference whether the pump is loaded or no load

I haven't looked at stator resistance but ran motor ID which i assumed calculated the value

this is something I have never encountered before on any other inverters 

I have used

Regards

Mel

As a suggestion, try this possible work-around:

Right before the point where the drive currently gets enabled and gets a speed setpoint, do it like this instead... Enable the drive with a 0 rpm speed setpoint, wait for about a second (experiment to find suitable delay), then give the drive the correct speed setpoint.

Try reducing the ramp up rate by 50% and see if it behaves the same way.  If the new ramp rate reduces startup wobble and it's acceptable, you're done :)

If either of them work but are not acceptable work-arounds, you can try manually adjusting motor ID tuning parameters so that it does not wobble at startup.  Remove the delay when it stops wobbling.

I had a similar problem with the ATV58 before.

The problem was with the IGBT leak.

But I think your problem is something else. 

You may have 'Start on The Fly' enabled. This is the drive checking for the rotor speed and direction and is the drive working correctly.

Tractor

Hi all

thanks for your suggestions I tried with the setpoint a zero and altering the ramp and it still did the same 

I will try on monday to see if on the fly setting is on I never thought of that 1

Regards

Mel

Mel

Hi all

thanks for your suggestions I tried with the setpoint a zero and altering the ramp and it still did the same 

I will try on monday to see if on the fly setting is on I never thought of that 1

Regards

Mel

 Are you sure the pump is correct?

The bearing may need service.

When the pump is off, the shaft rotates easily.

Do you have a one-way valve in the pump path?

Do you have no return water flow in the pipes? 

Hi All 

thanks for your replies turns out this was due to U/f control with linear characteristic and FCC

being selected

Regards

Mel