Chapter 7 - DC Motor Starters

Question 1

Why are starters needed on DC Motors?

Answer 1

A starter is used to Limit Starting Current until the motor has run up to speed and the Back E.M.F is Large enough to limit current to a Safe value.

Question 2

What are the basic requirement of a DC Motor Starter?

Answer 2

1. The Starter must Limit starting Current to a safe Value
2. the starter must protect the motor from excessive current caused by overloading or Fault.
3. The Starter must return to the start position if Power fails.

Question 3

What is the purpose of the ‘no Volts’ release coil?

Answer 3

the ‘No Volts’ release coil is there to hold the starter on while the motor is running if power is lost due to a trip or loss of supplies the coil is de energised and the spring loaded handle which was held by the coil is released and return home to the off position.

Question 4

Explain How the Faceplate starter protects a motor from excessive current.

Answer 4

The Faceplate Starter is fitted with an Overload trip so if current increase to high (due to a blockage/siezeur in what ever the motor is driving) the overload trip will operate stopping current flow protecting the motor.