DOL motor starting current & MCCB selection

Good morning

I have a question to address to more experienced people in here

I have a three phase DOL motor, 5.5kW, 11A with 130A starting current

This is going to be fed off a thermomagnetic MCCB

Before I see the starting current I was inclined to use a 16A MCCB

However I have now reservations due to the very high starting current

How can I select an MCCB in this case?

Is there a rule of thumb?

I am looking at a 40A MCCB now however this is more of an instinct rather than knowledge or experience.


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  • Mike, we are feeding it through a TMD MCCB, not an MCB so I cannot select the curves

    I am trying to find in the pdf something relevant to the starting duration however there is nothing. Only the starting current.

    I dont think it would last more than 5-10 sec though

  • Thats all I have

  • OK so lets assume 150A for 5 seconds. If we consider Schneider, but if you say your preferred we can use that, then their larger TM_D units allow the thermal and magnetic parts to be set independently

    Though their  smaller sizes have the magnetic part set permanently at about ten times the thermal, which is then the single adjustable.

    something like a 25 a unit wound down to 16 or so perhaps?