Circuit breaker motor selection

Update date:2018-06-21 Source:MAXGE

Circuit breaker motor selection

We generally call Miniature Molded Case Circuit Breaker as an open type. It has two series, one is a power protection type - D type, one is a light protection type - C type; when using open type in the selection, the note: C The type selection coefficient is 1.5-2 times, and the D type selection coefficient is 1.25-1.5 times. With a total molded circuit breaker selection coefficient is 1.15 times.

AC contactor

Air-opening option: The motor rated current multiplied by 2.5 times, the setting current is 1.5 times that of the motor, so that frequent start-up is guaranteed, and the short-circuit action is ensured; Contactor: AC contactor selection is 2.5 times the motor flow; Selection: It is selected based on the current size.

MCCB

For example: a three-phase asynchronous motor, 7.5KW, 4 pole, its rated circuit is about 15A.

1. The choice of air-opening: generally choose its rated current 1.5-2.5 times, the rated current of the motor multiplied by 2.5 times, the setting current is 1.5 times that of the motor, so that frequent start-up is guaranteed and the short-circuit action is also guaranteed.

AC contactor assistance

2, the choice of contactor: According to the motor power to select the appropriate size on the line, 1.5-2.5 times, but also pay attention to the matching of auxiliary contacts, not to buy back when the auxiliary contact is not enough. AC contactor selection is 2.5 times the motor current. This will ensure long-term frequent work.

3, the choice of wire: According to the rated current of the motor 15A, select the appropriate current carrying capacity of the wire, if the motor is frequently started, choose a relatively thick line, on the contrary can be relatively fine, there is a relevant calculation of the load limit, here we choose 4 square.

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www.maxge.com All Rights Reserved.

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