STARTERS IN DC MOTORS

Which D.C. motor is preferred for elevators

• Shunt motor

• Series motor 

• Differential compound motor 

• Cumulative compound motor 

By looking at which part of the motor, it can be easily confirmed that a particular motor is D.C. motor? 

• Frame

• Shaft

• Commutator

• Stator

A three point starter is considered suitable for 

• shunt motors 

• series motors 

• compound motor

• all D.C. motors

Four-point starter is used when

• 1. Motor field current is varied in a narrow range

• 1. Motor speed is varied in small range

• 1. Motor field current is varied over wide range

• 1. Can be used anywhere

Which of the following are protective devices in DC motor Starter?

• 1. No volt coil

• Over Load Coil

• 1. Both 1 and 2

• None

Which of the following are the disadvantages of a three-point starter?

• 1. Field Current Become weak

• 1. Disconnect the motor from the supply

• 1. The flow of current through the shunt field is decreased.

• 1. All of the above

A 3- point starter is used to:

• 1. Minimize back emf

• 1. Minimize armature current

• 1. Maximize armature current

• 1. Maximize back emf

What will happen if DC motor is used without starter?

• 1. Heavy sparking at brushes

• 1. It’ll start smoothly

• 1. Will not start at all

• 1. Depends on load

Which of the following types of starters are used in DC series motors?

• 1. Two-point starters

• 1. Five-point starters

• three point starter

• 1. Four-point starters

In a four-point starter NVC is connected  _______ across the supply.

• 1. Series

• 1. Parallel

• 1. Independently

• 1. Series Parallel