The motor plays a crucial role in the operation of an electric hoist. If the electric hoist is equipped with a dual-speed motor, it has both fast and slow speeds. Its main function is to allow for easy control of the speed when lifting and lowering objects, reducing the inertia of the objects during lifting and lowering, as the inertia is greater at high speeds.
Electric hoists are the most widely used light-duty lifting equipment. Their working characteristics include repeated short-term operation, frequent lifting, reversing, and braking, frequent overload, and often operating in dusty and metallic dust environments. They also generate strong vibrations during operation. Therefore, in order to meet the needs of electric hoists, the motor, as their main power source, should have the following characteristics:
1. First, the motor of the electric hoist should have stronger intermittent cycle working characteristics than ordinary industrial motors. The duty cycle, number of contacts, and number of lifting operations are important parameters for motor selection.
2. The electric hoist motor should have better lifting torque and overload capacity.
3. Electric hoist motors have smaller rotor rotational inertia, a larger rotor length-to-diameter ratio, and less visual braking.
4. The motor of the electric hoist should have a maximum safe speed that is several times the rated speed, generally about 2.5 times the synchronous speed.
5. Electric hoist motors should be adaptable to different working temperatures and humidity levels, and should have at least two identical insulation classes.
Due to the continuous development of insulation technology, the design of motors requires both increased output and reduced size, resulting in smaller and smaller heat capacity and weaker load capacity of new electric hoist motors. Furthermore, due to the increasing degree of automation in production, motors are required to operate in a variety of modes such as frequent starting, braking, forward and reverse rotation, and load changes, which places higher demands on motor protection devices.
