For pump or fan drives, under what circumstances is a pulley used instead of a coupling with an electric motor?
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For pump or fan drives, in what situations is it necessary to use pulleys instead of couplings with electric motors? How should they be selected?
It depends on the speed of the pump or fan, as the speed of the motor remains constant. Synchronous speed of 2-pole motor: 3000 r/min ； The synchronous speed of a 4-pole motor is 1500 r/min ； The synchronous speed of a 6-pole motor is 1000 r/min ； The synchronous speed of an 8-pole motor is 750 r/min. The rotation speeds of pumps and fans may not match those of the motor, so they cannot be connected directly and a transmission mechanism must be used! Transmission methods include belt drive, chain drive, gear drive, worm and worm gear drive, and so on. Therefore, belt drives are widely used due to their simple installation and low cost, but they are prohibited in flammable and explosive environments!
What was said upstairs is very detailed. In simple terms, if the rated speed of the pump is the same as that of the motor, then they can be connected directly; if not, auxiliary devices such as belts are needed for transmission
The rotation speed can be achieved through gears or reducers. But isn’t it easy for the belt connection to slip and break? Using it for a long time is definitely not good. It should be phased out by now.
Generally, variable speed is achieved using belt drives, but when designing such drives, it should be taken into account that the linear velocity of the belt should not exceed 35 m/s.