Breaker charging current

[lj]

I am trying to design a control power circuit to provide 120Vac to operate breaker closing coils/charging motors. There are ten breakers to be served and up to six motors can be charging at the same time, so the relay contacts in the control circuit must be sized to handle all that current. I heard that breaker charging motors operate for about 5 seconds, but I can't find the motor current draw in any manufacturer's literature, so I can't specify the current rating of the relay contacts. I'm afraid it may require 30 amp or 40 amp relay contacts, which seem hard to find. Does anyone have data or rule of thumb for sizing contacts to support charging motor current? 1000 thanks.

 

[Jraef]

It's pretty small. You didn't say whether you have Power Breakers or motorized MCCBs, but on the Siemens WL Series Power Breakers, the charging motor is 110W, charging time is < 10sec. The closing / shunt trip solenoid actually takes more power at 120W, but only for a second or less of course.

 

[lj]

It so happens that the breakers are Siemens WL. Thank you, Jraef, for the prompt reply and excellent answer.

 

[Jraef]

Glad I could help.

That information by the way is in the manual, under Technical Data, chapter 24.

 

[lj]

After you gave me the tip, I found it also in Siemens' Selection and Application Guide, page 1/34. Thanks, again!