1. The first category: 1 KV and above 1 KV voltage is called high pressure, such as 1 KV ,3 KV ,6 KV, 10 KV ,35 KV ,110 KV ,220 KV ,330 KV ,500 KV;
2. The second category: below 1 KV voltage is called low pressure, such as 220 V, 230 V, 380 V, 415 V, 660 V;
The third category: below 50 V voltage is called safe voltage, such as 12 V, 24 V, 36 V, 48 V. So the hoist power supply voltage is low pressure and control voltage is safe voltage.
The requirement of electric hoist power supply use 3P +PE power supply system (3P is Power supply wire, PE is ground wire), stressed to provide the ground wire, the track will not be used as a ground protection circuit. Under normal operating conditions, the voltage fluctuation at the access point of the lifting machinery shall not exceed 5% of the rated value.
In the power system of the world, there are two kinds of power frequency, one is 50 Hz, and the one is 60 Hz. Industrial voltage is different in each country, for example it is 3 phases, 380 V, 50 HZ in China, but in Philippines it 3 phases, 220 V ,60 HZ. Although both are located in Asia, and the distance is very close, but there is a great difference between the voltage and frequency. The maximum safe voltage for human is 50 V. So the control voltage must be less than 50 V.
The civilian voltage is single phase and the frequency is the same with industrial frequency. Usually the industrial voltage is 1.73 times the civilian voltage.
In use process, electric hoist is hard to avoid failure. In order to do well to the safe operation of electric hoist, timely and accurately process all kinds of faults has become an important part of construction production.