Electric hoists represent their own machinery, strength, and toughness, while the stage is elegant, flowing, and soft, with conflicts and collisions between the two.

Chain Block Dual Brake Motor


Brief Explanation :

How can electric hoists operate safely under undervoltage?

Category : V7 Stage Electric Series

Get a Quote

Product Details

How can electric hoists operate safely under undervoltage?

In practical life, the voltage fluctuation of power grids in many regions is significant, and even 380V voltage sometimes drops to 300V or even 260V. This has a serious impact on the electric hoist motor. Once the power supply voltage is unstable, it directly weakens the magnetic field of the contactor, greatly reduces the reliability of suction, and often causes the iron core of the contactor to vibrate continuously. The circuit also breaks with time, and the contactor contacts are very easy to burn out. It can take a few days to replace the contactor, or even directly burn out the motor. On the other hand, electric hoists controlled by contactors are prone to accidents.

In fact, as long as the number of turns of the original contactor coil is removed, for example, the 380V40A contactor coil was originally 3600 turns, and 720 turns can be removed (other working voltages and capacities can be extrapolated). The author has made the above modifications to four electric hoists, some of which have been operating safely for over five years, and the contactors can reliably close when the power supply voltage drops from 380V to 260V; When the voltage rises to 480V, the contactor still operates safely. This is because the electric hoist is always in a short-term intermittent use environment, with six strokes of east, south, west, north, up and down, and each working time will not exceed 5 minutes.

As for contactors that operate under long-term working conditions and motors that use contactors for undervoltage protection, the excitation current will increase significantly due to a decrease in coil turns. This method cannot be used to prevent equipment damage