Minimal output current

Hello,

is there defined minimal current/power limit for Sinamics power modules PM240-2? I mean how small motor I can connect to power module? I cannot find it in manuals or technical datas, everywhere is maximum current limit..

Is it limited by power module with next smaller power or there is some % of nominal current?

Regards

Hi,

indeed there is a limitation due to the resolution of the current transducers which cannot measure these low currents.

In the catalogue D21 you can find values at least for SINAMICS S120 Booksize Motor Modules for Servo, Vector and V/f control.

https://support.industry.siemens.com/cs/ww/en/view/109747019

In general those are the recommended values you find in that catalogue:

The permissible relation motor current / module current is for Servo and Vector control 1:4 (motor 4 times smaller than module). In the range from 1:4 to 1:8 it is still possible but with restrictions regarding torque accuracy. From 1:8 to 1:12 it is still possible just with V/f control.

Servo: 1:1 - 1:4 (up to 1:8 with restrictions)

Vector: 1,3:1 - 1:4 (up to 1:8 with restrictions)

V/f: 1:1 - 1:12

Hello,

I appologize for useless post I finally found it in hardware installation manual. There is section about permissible motors and the range is 25..150% of nominal power of PM240-2 for 200V/400V versions and 50..150% for 690V versions.

Regards

Hi Robert,

thank you very for your help, I found only remark in hardware installation manual..

Thank you

Regards

Ah perfect, see so I learned something new as well.

So: the values from above are just valid for SINAMICS S120 Booksize Modules!