90kw pump star delta start, in the end to use the circuit breaker, AC contactor (Star contactor, angle contactor), what kind of thermal relay?
Imports, such as Schneider, press: plastic case press 250A, contactor select 115 of 2, 95 of 1 can.Domestic recommendations: Press: plastic case press 250A, contactor 160, 2, 115 of the 1 can.
The first thing to take the star delta start voltage step-down start, star rated by reducing root 3 times, power is also reduced, 90kw / V 3 = 52kw starting current is 5---7 times will reach the rated current of 52kw * 2 = 104A, starting current will reach 500----700A is normal, if you match breaker sister ordinary 800, D at the beginning of the special motor, they start filtering instantaneous current, 250 can be,The star delta starts with only three contactors, and there will be no 4The contactor can be more than 110
The star delta circuit you give belongs to the international standard starting mode, different from the old gb. The first said (the old national standard, is actually the domestic elders step-down manner, they are the main contactor) after shunt implementation of star triangle, so there will be a larger contactor, down economic calculation.And the new international standard (you give the circuit diagram) can be seen that the air switch to select the motor current to meet the given amount of surplus, 90kw motor rated current 175A, so choose 225A air switch can be. 1KM 2KM is the main operation of contactors, contactor, they each pay half the current line in triangle, so choose 110A (like never seen 100A) current, 3KM star, because of short-time current will not cause damage to the contact, a little lower 80A is not affected. Heat meter: if you don't use a transformer, you can choose JR36---160A.Some friends may feel small, in fact as long as you pay attention, you will find a lot of electrical equipment factory are doing this standard. In this way, both cost savings and service requirements are met.
