Electronic Soft Starter

ENERGY SAVER SOFT STARTERS belong to the latest generation of motor starters, incorporation state-of-the-art technology. They are far superior to any of the conventional electro-magnetic modes of starting as they can provide a smooth start, reducing the in rush currents considerably, besides offering several other advantages. Further, the built-in energy saving facility helps in reducing power consumption when the motor is partially or cyclically loaded.

Soft Start

The starting current drawn by an industion motor is directly proportional to the applied voltage. The Soft Starter is designed to make it possible to choose the lowest voltage possible (pedestal voltage) at which the motor can be started – the lowest voltage being dependent on the load on motor.

The voltage is ramped up from this pedestal level to full voltage in the set time (selectable 0 to 30 seconds). Pedestal voltage and ramp time can be set at site. It is also possible to Provide controlled torque soft start with current limit option. Soft start feature can also be provided, as Optional.

Energy Saving

A majority of induction motors in industries are under utilized due to a combination of design / selection / safety considerations. This results in substantial energy loss, by way of wasted power and consequent rise in the temperature of the motor, which is harmful to the motor in the long run.

ENERGY SAVER SOFT STARTERS are ideal for saving energy when used with induction motors which are operation at partial or no loads. They automatically control the voltage applied to the motor, to that required to meet the varying load conditions without sacrificing torque or speed, resulting in reduced power consumption and consequent saving in KWH and improved power factor.

Energy Saver Soft Starters Are Ideally Suited

  • Where a smooth start is desirable to avoid shocks to the drive systems or where a gradual start is required to avoid damage to the product / process / drive system and accessories.
  • Where system voltage drop is to be eliminated or undue loading of generators is to be avoided.
  • Where in-rush current is to be limited to avoid heavy line voltage drop while startin high capacity motors or high inertia loads.
  • For reduction of maximum demand when motors are started frequently.
  • Where energy saving is desired under partial or cyclic load conditions and to improve power factor.


  • Smooth start and Stepless Gradual acceleration of motor and consequent elimination of shocks during starting.
  • Reduction in peak motor current during starting.
  • Reduction in maximum demand.
  • Reduction in motor temperature, increased motor life and decresed maintenance.
  • Comfortable lnching without any damage.
  • Power factor improvement.
  • Reduced power consumption and hence reduced Energy bills.
  • No moving parts that can be affected by dust, dirt or other such environmental factors.
  • Easy installation and Retrofit capacity (3 wires in 3 wires out) – solid state – low maintenance.
  • Replaces electro – magnatic starters as well as fluid couplings.

How Energy Saver Starter Works : Principle

ENERGY SAVER SOFT STARTER consists of Silicon Controlled Rectifiers (SCRs), sensing and control circuits to control the firing of SCRs. Soft Start is achived by progressive phasing back of the firing of SCRs in the present time. To achieve energy saving the phase angle between the voltage current is monitored continuously to obtain a signal proportional to the phase angle, based on which the firing of the SCRs is controlled. When the phase angle increases, (which is indicati of low power factor), the control circuit adjusts the firing angle to decrese the average voltage applied to the motor and vice versa.


  • Soft Start facility, with initial torque setting by minimum pedestal voltage, Ramp time settable for setting ramping time, adjustable from 0 to 30 secs.
  • Energy Saving.
  • In built Micro corntroller based Protection for Motor like Single phsing, Unbalanced, Over load, Locked Rotor Short circit etc.
  • Annunciation for all above fault by digital display as well as indication for Motor run etc.
  • Push buttons for start and stop.
  • Energy saver disable facilities.

Fault Annunciations

Power input 415/440 volts AC + 10% 3 phase 50 hz.
Recommended load A.C.Motor, three phase, Multiple Motors or other loads are not recommended except under specific circumstances.
(Consult us for further details)
Maximum Over load capacity 115% continuous, 150% for 10 seconds and 200% for 5 seconds.
Altitude of Installation 1000 meters (Above 1000 meters derating has to be done)
Voltage rating of Thyristors 1400 to 1600 PIV.
Types of cooling Air-cooled upto 75 HP. Force-cooled above 75 HP.
SCR Protection MOV transient voltage suppressors to absorb high energy voltage transients provided acoss the input supply points. RC snubber circuit is provided across SCR to prevent misfiring due to rapid rise of voltage.