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The complete power supply and control programme for motors [t-head1-first]
As the applications differ, so do the requirements made of the electric drives:
- In the simplest case, the motor is switched with an electromechanical contactor. Combinations consisting of motor protection and line protection are termed motor starter.
- If frequent and/or silent switching is required, contactless semiconductor contactors are used. In addition to conventional line, short-circuit and overload protection, superfast semiconductor fuses are required for type “1” coordination and may be needed for type “2” coordination.
- During DOL starting (star-delta, reversing starter or pole-switching), unwanted current and torque peaks occur. Soft starters eliminate these to ensure gentle starting and prevent an excessive burden on the power source.
- Where an infinitely adjustable speed or a torque adjustment is necessary, frequency inverters (U/f inverters, vector frequency inverters, servo) are used today.
As a general rule, the application determines the drive.
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