Chapter 6, Problem 6RQ

Explanation of Solution

a.

Schematic diagram of AC magnetic motor starter:

The schematic diagram for an across-the-line AC magnetic motor starter is given below:

Explanation:

• The above given schematic is of a three phase magnetic motor starter as AC signals mostly prefer three phase system...

Explanation of Solution

b.

i) Function of main contact M:

• The main contact M is placed in series with the motor.
• It is used to complete the path to the motor.
• It is a part of the power circuit and is built in such a way that it could handle full load current of motor.

ii) Function of control contact M:

• The control contact M is placed parallel to the start button.
• It is provided with an address similar to that of the starter coil M.
• It is used to keep continuity in path from left end of the rail to starter coil M, even though the start button is released.
• It is more than enough to handle small amount of current that is needed to energize the coil.

iii) Function of starter coil M:

• The starter coil M is placed in series to the start button...