For 7.5kw star delta starter how to calculate


1. Mccb rating
2. Contactor rating
3. Over load relay rating



For 7.5kw star delta starter how to calculate 1. Mccb rating 2. Contactor rating 3. Over load rela..

Answer / joeredd

You need to know the full load motor current at the supply voltage you are going to be using. Your contactors/overload are rated on current. Their voltage rating needs to be higher than the supply voltage.  (I.e. 415vac supply, 600vac rating). Knowing the motor wattage (7.5Kw) on its own is not helpful. 

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