In industrial and agricultural production, we often use plastic case circuit breakers. Three-phase asynchronous motors carry a wide variety of fault information, one of which is that a three-phase asynchronous motor running out of phase is a common fault. Let's start with what happens when a motor is out of phase and what causes it.

A molded case circuit breaker is a circuit breaker for a three-phase AC short circuit in one phase in the motor stator winding. When the motor is missing a phase, if we need to energize the motor to start at this time, then for a motor can be used as a business will generally issue a "buzzing" sound, and can pass the motor speed up more slowly. When the motor is driven by a heavy load, it cannot reach the speed specified in the starting state, or even start. This state will continue for a long time, the motor will be us because they long time high current thus leading to internal control motor overheating, serious problems will smoke and fire burned.

In the three-phase asynchronous motor running process, if the sudden lack of phase, the motor speed will quickly drop, the motor stator winding current will also greatly increase, while the abnormal "buzzing sound" will be generated, the motor can not run for a long time, or the three-phase motor will burn out. We can use the dinging sound to remember the hazards of three-phase motor running without phase, that is, "motor running without phase, early elimination of disaster can be avoided".

Three-phase motors without phase can generally be summarised as two types of three-phase motor external and three-phase motor internal:

External causes of phase loss in moulded case circuit breakers: In a large number of maintenance management cases, it is common for the motor to have loose wiring screws in the junction box; secondly, loose or oxidised connection points in the circuit of the three-phase AC power system, such as part of the contactor contacting the society poorly or contacting a resistance temperature too high, leading to a lack of phase in the working power supply; and fuses in the fuses are broken or not tightened, etc.

Internal causes of phase loss in the moulded case circuit breaker: Internal causes are rare and are generally the leads of the three-phase motor circuit breaker. At this point we can measure the DC resistance of the three phase winding, if there is a large or infinite single phase resistance value, then the winding is open phase.

So the three-phase motor running out of phase is very harmful to the motor, and we as teachers can study the need for data IT protection by using students to learn some social environmental protection business management measures for three-phase motors running out of phase. For example, an enterprise can design and use thermal relays with phase break protection for phase break protection, for the stator winding into Y type, we can choose to use two-pole or three-stage structure of the thermal relay phase protection; if the motor stator winding into the triangle

The above is Huatong share the knowledge related to three-phase motor phase loss. Welcome to visit our website for more information.