G120 PM250 Voltage Hunting

Dear Experts,

I am doing the new commissioning of sinamics G120

1. CU=Cu240E-2

2.PM= PM250(Regenarative module).

Actually before giving the ON command the DC link voltage will be 560volts normal.

Once i have given On command DC link voltage goes to 460volt.

So i taken a trace and found in that 460 volts also continuously hunting..

I have attached the trace file for your reference.

And i want to know what will be the reason for voltage Dip and voltage hunting if i given the ON command. And i checked without connecting the motor and with connecting the motor, but same responce. Even i checked 4 power module.. And all will be the same response with voltage dip...

there are total 8 drives.

thanks in advance

Thanks for your valuable reply,

Can you just explain technically what happen exactly after giving the ON command..

And read parameter actual DC voltage is 460volts(not 520volts).

Is there any possibility to increase the voltage(DC Link) or is there any possibility it will trip on Undervoltage fault.

Thanks in advance

Regards

Gopinathan P