According to the usage, there are 3 types of motor protection circuit breakers:

1. AC contactor is used for starting and breaking of the motor, and thermal relay is used for overload protection (in addition to overload protection, thermal relay also has the return characteristic of avoiding the starting current of the motor, which also belongs to the overload range) , And the open circuit protection is used for short-circuit protection. Because the contactor is used to divide and close the circuit, it can be operated more frequently

2. Use the contactor to start and stop the motor, and the faults such as overload, short circuit and undervoltage of the motor are borne by the open circuit

3. The motor is operated and protected by a circuit breaker during starting, breaking, overload, short circuit, and undervoltage, but it cannot be used frequently

Types and characteristics of motor protection circuit breakers

Motor protection circuit breakers can be divided into two types, which only have short-circuit protection function and both overload and short-circuit protection functions. The tripping device of the former is electromagnetic or electronic, and the tripping device of the latter is thermal magnetic or electronic. The common point of the motor protection circuit breaker and the distribution circuit breaker is that they all follow the GB14048.2 low-voltage circuit breaker standard. The difference is that the overload protection characteristics of the motor protection circuit breaker must meet the overload relay trip in the GB14048.4 contactor and motor starter standard. Level requirements, overload protection characteristics are consistent with thermal relays. Because of its instantaneous tripping current threshold, the D-type miniature circuit breaker can avoid the peak of the motor starting current. It is often used for motor short-circuit protection, but it cannot provide suitable overload protection. It needs to be equipped with a thermal relay. The return time of the motor protection circuit breaker at 7.2 times the current must be greater than the motor starting time to avoid long-delay protection action during the starting process, and its instantaneous protection setting value must be greater than the peak value of the motor's on-current to avoid short-circuit instantaneous protection errors during starting action.

Use

The circuit breaker should be installed vertically, and before installation, check whether the technical parameters listed on the nameplate of the circuit breaker meet the requirements for use.

The circuit breaker should be manually operated several times before energizing, and its mechanism action should be flexible and reliable without blocking.

Press the close button (black), the circuit is in the on state; press the disconnect button (red), the circuit is in the off state.

During use, the circuit breaker should be checked regularly (usually one month), that is, when the circuit breaker is closed and energized, toggle the test button (the test button is represented by the symbol "Test"), the circuit breaker should be reliably disconnected.

When the circuit breaker is disconnected due to an overload or short circuit fault in the circuit, the circuit breaker should be re-closed after troubleshooting.

This circuit breaker is a non-maintenance type, so when the circuit breaker fails to work normally, the user is not allowed to open the circuit breaker for maintenance.

When using the current adjustment knob, it must be adjusted to the corresponding position according to the actual current of the line.

Company Profile

Zhejiang ETEK Electrical Technology Co.,Ltd.was founded on January of 2011, which has more than 200 employees now. It is a professional manufacturing company engaged in R & D, production and sale of high and low voltage electrical products, such as terminal distribution electrical appliances, industrial distribution electrical appliances, industrial control electrical appliances, DC systems distribution appliances, etc. it possesses 3 major manufacturing departments and 1 import & export trading company. The three manufacturing departments are terminal distribution electrical appliances manufacturing department, industrial distribution electrical appliances manufacturing department and industrial control electrical appliances manufacturing department.

E-mail:sales@etek-china.com 

Tel: 86-577-62780116/62718777

Fax: 0086-577-62774090