The following three main factors should be considered in the selection of explosion-proof motors
1. After the voltage, frequency, and speed are determined, the installation factor K is selected to determine the motor power according to the load being driven by the motor and the condition of the power supply network. Check the installation size from the motor catalog by the installation method. There are also cases where the motor power is selected from the sample from the determined center height.
2. Confirm whether the technical indicators meet the requirements (the supplier and the demander will finalize in the technical agreement). For the wound rotor motor, in order to select the matching starting and speed regulation system, the supplier also needs to provide the values of the rotor voltage U2 and current I2.
3. Determine the protection level and explosion-proof type, explosion-proof level or anti-corrosion category and level according to the use environment, as well as other requirements, such as outdoor and marine use. Can refer to: explosion-proof motor temperature group and explosion-proof category.
Pay attention to the following three points when selecting explosion-proof motors
1. The explosion-proof grade of the explosion-proof motor should meet the requirements of flammable and explosive environment. Don't choose the high grade.
2. Determine the technical indicators according to the actual usage. The higher the η and cos φ in the technical indicators, the better, which saves power, but the other indicators are not. For example, for motors that drive axial-flow pumps and fans, Tst should be in the range of 0.6 to 0.8, and Tm does not need to be high, and about 1.6 can meet the requirements. If the buyer looses a little bit on these two indicators, the designer can add the excess functions dug out from this to Ist, which is used to reduce Ist. This is of practical significance for places where the network capacity is small. The load of the two-pole motor is mostly fans and pumps, and Tst is not necessary. If the manufacturer pursues this index too much, the upper half of the cast aluminum rotor trough is designed to be very narrow, which adds unnecessary difficulty to the manufacturing; there are many faults caused by broken bars and thin bars during use.
3. The protection level should be selected moderately. The difference between IP54 and IP44 is mainly in the dustproof function. In order to save money, some buyers choose IP44 motors in places where IP54 should be used, causing the motor bearings to be damaged prematurely. On the contrary, when IP44 can meet the requirements of use, there is no need to choose P54. The latter should be equipped with a rubber sealing ring, which is not as good as the former in terms of maintenance.