Constant Temperature And Humidity Test Chamber Dongguan Best Instrument Technology Co., Ltd , https://www.dgbestinstrument.com
Fault prediction of mine explosion-proof magnetic starter
Mine explosion-proof magnetic starters are used in mines with gas or coal dust explosion hazards.] The function of fault prediction is to control the fault condition of the motor and power supply cable! Leakage, short circuit, short phase, before power transmission Pre-detection, when the electric motor and cable before power transmission have electric leakage, short circuit and broken fault, the magnetic starter is locked by fault blocking.
It can't close the power transmission, so that the failure point of the cable and the motor will not cause fault damage due to no power, which ensures the security of the power supply, and more importantly, the failure point will not be energized because of the role of fault blocking. There is no exposed spark or arc at the point of failure. This is especially important to prevent coal gas dust explosion in mines. The fault blocking of mining explosion-proof magnetic starter is divided into electric leakage blocking, short-circuit blocking and phase-locking blocking, which have different effects.
Leakage blocking
Leakage blocking refers to the prediction of the relative insulation between the electric motor and the cable feeding the electric power before transmission. If leakage occurs, the magnetic starter is locked so that it cannot be turned on and transmitted to prevent transmission of electricity to the leakage point. Leakage faults and leakage sparks occur to prevent explosion of gas and coal dust caused by leakage spark leakage. The leakage lockout consists of two parts: leakage prediction and latching circuit. As shown in Figure 1
Short-circuit blocking
Short-circuit blocking refers to predicting the phase-to-phase insulation between the electric motor and the cable supplying power before transmission. If a short-circuit occurs, the magnetic starter is locked so that it cannot be turned on and transmitted to prevent transmission of power to the short-circuit point. Short-circuit faults and short-circuit arcs. In order to prevent the explosion of gas and coal dust caused by the exposure of the short-circuit arc, the short-circuit blocking is composed of two parts: the short-circuit prediction and the blocking circuit. as shown in picture 2