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The starting current drawn by an induction 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 the motor. The voltage is ramped up from this pedestal level to full voltage in the set time (selectable- 2 to 10 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 stop feature can also be provided, as optional. |
SOFT STARTER consists of Silicon Controlled Rectifiers (SCRs), sensing and control circuits to control the firing of SCRs. Soft Start is achieved by progressive phasing back of the firing of SCRs in the present time. Its micro controller operated device.
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.
1. Where a smooth start is desirable to avoid shocks to the drive system or where a gradual start is required to avoid damage to the product/process/drive system and accessories.
2. Where system voltage drop is to be eliminated or undue loading of generators is to be avoided.
3. Where in-rush current is to be limited to avoid heavy line voltage drop while starting high capacity motors or high inertia loads.
4. For reduction of maximum demand when motors are started frequently.
5. Where energy saving is desired under partial or cyclic load conditions and to improve power factor.
1. Smooth start and Step less Gradual acceleration of motor and consequent elimination of shocks during starting.
2. Reduction in peak motor current during starting.
3. Reduction in maximum demand.
4. Reduction in motor temperature, increased motor life and decreased maintenance.
5. Comfortable Inching without any damage.
6. Power factor improvement.
7. Reduced power consumption and hence reduced energy bills.
8. No moving parts that can be affected by dust, dirt or other such environmental factors.
9. Easy installation and Retrofit capability (3 wires in, 3 wires out) - Solid state - low maintenance.