Why Motor Starting Auto Transformers?
Motor Starting Auto Transformer's primary function is to limit inrush current and starting torque in AC motors under starting or locked rotor conditions. This eliminates the problems associated with line voltage drop, resulting from high inrush currents. This includes motor applications for driving fans, pumps, compressors, line shafts,etc.Full voltage starting of motors can produce voltage flicker, mechanical stress to gear boxes or belt drive systems and create pressure surges or water hammer in pumping applications. Starting a motor at reduced voltage can help reduce or overcome these problems.
The major advantage of this method of starting motors are: for hard to start loads, adjustable starting torque, can be used with any standard motors and less strain on the motor. Auto-transformer starting uses an motor starting auto-transformer to reduce the line voltage during the starting period. the auto-transformer voltage taps provide a choice of three different starting currents and torques, depending on the load requirements. In this system, the first step is connected to one of the reduced voltage taps, which results in a reduced starting current and torque.
A three-coil autotransformer is connected in a wye configuration and connected to the motor in such a way as to supply reduced voltage to the motor when the line voltage is applied to the Autotransformer. Several sets of taps are usually available to the user to provide different values of reduced voltage (NEMA standards are 80%, 65% and 50% of the full line voltage).
List of available motor starter auto-transformers are currently in stock or you can order from Canada Transformers: