Exam Question
(a) Explain about the working of D.O.L starting of A.C motor with the help of a diagram (8)
(b) Explain about the auto transformer starting of an A.C motor with the help of a diagram. (8)
Class 4 (4th Engineer)
MET
📅 Jul 2022
Reference Answer
### (a) Direct-On-Line (D.O.L) Starting of an A.C. Motor
Direct-On-Line (DOL) starting is the simplest and most common method of starting a three-phase squirrel cage induction motor. In this method, the motor is connected directly across the full three-phase supply voltage.
#### Principle of Operation
The principle is to apply the full rated voltage to the motor's stator windings instantaneously. This results in the motor producing its maximum starting torque, but also drawing a very high starting current from the supply line.
Direct-On-Line (DOL) starting is the simplest and most common method of starting a three-phase squirrel cage induction motor. In this method, the motor is connected directly across the full three-phase supply voltage.
#### Principle of Operation
The principle is to apply the full rated voltage to the motor's stator windings instantaneously. This results in the motor producing its maximum starting torque, but also drawing a very high starting current from the supply line.
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