Page 329 - Electronic Mechanic - TP - Volume - 2

ELECTRONICS MECHANIC - CITS

Observation table:

Table 1: Variation of speed below base speed. Table 2: Variation of speed above base speed.

Sl.No Armature Voltage (V) Speed(rpm) Sl.No field Current (A) Speed (rpm)

Result and discussions: Draw power vs speed and torque vs speed characteristics.
Precautions:
• All connections should be tight.

• Don’t touch live terminals.
• Don’t insert the resistance in field winding, when motor begins to start.
• Reading should be obtained carefully.
Pre experiment questions:

• What are different methods of speed control of DC motor?
• Draw Power vs Speed and Torque Vs speed Characteristics for Ward –Leonard method.?
Post experiment questions:
• Explain Power vs Speed and Torque Vs speed Characteristics for Ward –Leonard method.?
• In order to increase the speed above rated speed, which method of speed control is used in DC shunt motor?

• In order to decrease the speed below rated speed, which method of speed control is used in DC shunt motor?

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CITS : E & H - Electronics Mechanic - Exercise 220