Use and scope of application

NMDZ20 series plastic case circuit breaker rated insulation voltage is 660V, AC 50Hz or 60Hz, rated working voltage 380V and below rated current to 1250A, generally used as power distribution, rated current 225A and below and 400Y type circuit breaker can also be used as protection For electric motors, under normal conditions, circuit breakers can be used as infrequent line switching and infrequent starting of the motor.

The NMDZ20 circuit breaker is based on the Y-type and consists of four parts: the insulating housing, the operating mechanism, the contact system and the trip unit. The operating mechanism of the circuit breaker has the function of quickly closing and breaking the contacts, and the "close", "divide", "refast" and "free trip" positions are distinguished by the position of the handle.

Type C, J and G circuit breakers are derived from the Y-based basic product (except C-type 160A). The J-type circuit breaker is to improve the structure of the contact of the Y-type circuit breaker, so that in the case of a short circuit, before the mechanism is actuated, the movable contact can be quickly disassembled to achieve the purpose of improving the on-off capability.

The G-type circuit breaker is a repulsive current-limiting contact system consisting of a parallel conductor connected in series behind the bottom plate of the Y-type circuit breaker. The system is longer than the J-type repulsive contact and has a large breaking distance, so it can be more quickly limited. flow.

The neutral pole (N) of the four-pole circuit breaker is not equipped with a tripping element and is located at the rightmost position. In the process of splitting, the neutral pole is specified to be in contact with the other three poles when closed, and disconnected from the other three poles when opening.

The C-type circuit breaker is designed to meet the power distribution protection in the transformer power grid of 630KVA and below. It can achieve better economic results by selecting the simplified structure of economical materials and improving the process.

Model meaning

Dimensional parameters