Energy saver soft starter with current limit soft start facility is used with induction motors for obtaining soft start, energy saving and protection from overload and single phasing. The induction motor normally draws full magnetising current when the rated voltage is applied. This happens at lower loads also, when is is not required, resulting in iron and core losses in the form of heat, reducing the efficiency considerably. Also the power factor is low, as reactive current higher than required is drawn from the supply. With the energy saver soft starter, a gradual start is obtained with a fairly low starting current. After achieving soft start, the starter automatically and continously adjusts the voltage to obtain optimum operating voltage based on load. Other advantages include reduced motor temperature and increased life, jerk free starting, etc. The net savings in energy and reactive power achieved will depend upon the load on the motor. Saving is of the order of 50% on no load, gradually going down as the load increases. Reduction in the reactive power is of the order of 80% on no load. With all the above advantages, the present electro-mechanical starters can be replaced to obtain the advantages of soft start, energy saving and reliable protection.
