When choosing a motor for an application, a primary consideration may be the speed range it’ll be operated in. When a motor is run considerably slower than its rated base speed, numerous potential adverse effects may come into enjoy, including reduced cooling efficiency, reduced power effectiveness and a change in the motor’s velocity and torque characteristics. To mitigate this issue, some motors and velocity controllers have already been designed especially to drive lots at low speeds with exact control.
Most domestic and industrial motor applications use 3-phase asynchronous induction motors, which operate at a speed that’s determined by the frequency of the supply power. When an application operates at a constant speed, the only thing that is necessary could be a gearbox or rate reducer that brings the engine speed down to the required level. However, many applications need the acceleration of the engine to be varied during operation.
This is normally achieved utilizing a VFD or Variable 
Frequency Drive, which controls the speed by modifying the frequency fed to the motor. Selecting the most appropriate engine and VFD type depends upon a variety of factors, however, it’s important to 1st look at the way the characteristics of a electric motor change when the quickness is reduced.
A motor usually includes a base speed, specific by the manufacturer, that it is certainly made to operate at. Nevertheless, if a electric motor is managed below the bottom speed, it could experience reduced efficiency of the coolant system. Especially with frequently used Totally Enclosed Lover Cooled (TEFC) and ODP (Open Drip Proof) motors, where in fact the cooling system consists primarily of a shaft-mounted lover, a reduction in speed outcomes in reduced airflow over the engine and lack of cooling, and temperature buildup occurs. Particularly when the engine is operated with complete torque at low speeds, heat can easily build up inside the motor to harming levels.
Gearboxes and speed reducers are mechanical velocity reduction equipment used in automation control systems.
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