Hi all,

Do we need any protection device for PM240-2 drive module?. When we select the drive article number through siemens configurator tool, it didnt suggested any Fuse or MPCB for protection. On our earlier project when we selected G120C it showed us a MPCB for protection as an optional unit.

On what basis we have to come to a conclusion that MPCB/ any protection is not needed?. How to arrive at a current rating value of MPCB. Is there any manual or notes available?

TechTeam

Hello,

here you will find the manual for protective devices at PM240-2:

https://support.industry.siemens.com/cs/ww/de/view/109486009

Hi,

In the protective devices for the PM240-2 manual the MPCB for the 6SL3210-1PE12 module, it was suggesting a 7-10A range MPCB while the input current will not go beyond 3A as per datasheet!. Then why do we need a high rated MPCB? Why can't we use an MPCB with range setting say 2.8-4A?

Since its a class 10 circuit breaker it will not trip for large starting currents.right?.

Why Siemens is suggesting a high rated protective device for a low input rating device. If we select a high rated MPCB the wire between MPCB and drive needs to be selected as per the MPCB range setting, that will unnecessarily make all things bulky.

TechTeam

Hello,

have a look here:

https://support.industry.siemens.com/cs/ww/en/view/60279172

and there in chapter 6.18.

As the inverter creates currents different to 50/60 Hz you have to select higher rated breakers.

 Sorry for the misunderstanding. I am talking about the MPCB protection for the PM240-2 module. 

There won't be any high-frequency current on the upstream of power module right?. 

Why do we need MPCB on the downstream of the PM240-2 module? PM240-2 has its own protection methods for motors right?