DC Series Motor Starter

TWO POINT STARTER

• It is used for DC Series Motor for the protection from High starting current based on resistance star method.
• Limit the starting current by adding resistance in series with the field and armature through NO Volt Coil or Holding coil.

          This contains the following components.

1. The series resistor required for starting a motor
2. The contacts (brass studs) and switching arm required to include or exclude the resistor in the armature circuit
3. A spring on the handle to bring to the OFF position when supply fails
4. An electromagnet to hold the handle in the ON position.

Working :

• Limit the starting current by adding resistance in series with the field and armature through NO Volt Coil or Holding coil.
• When the arm is moved to the first contact point, the circuit is completed, and the armature begins to rotate. As the armature speed increases, the arm is slowly moved towards the right side of electromagnet, there by the starter resistance is reduced. When the arm is against the electromagnet, complete starter resistance cut off from the circuit.
• The electromagnet is wound with a thick gauge wire to carry the rated armature current of the motor. This holds the handle in the ON position, when the motor is working. The handle comes back to the off position, due to spring action, when the electromagnet demagnetizes due to failure of supply. This starter in general will not have protection against over load.