Page 325 - Electronic Mechanic - TP - Volume - 2

ELECTRONICS MECHANIC - CITS

EXERCISE 218&219: To control the speed of a D.C.shunt
motor by Armature control method

and field control method

Objectives

At the end of this exercise you shall be able to:
• Practice to control the speed of a D.C.shunt motor by Armature control method and field control method.

Requirements

Tools/Equipments/Instruments
• Combination Plier 250mm - 1 No. • Voltmeter (M.C) 0-250V - 1 No.
• Screwdriver Set 150mm - 1 No. • Rheostat Wire wound 500 ohms, 1.2 A - 1 No.
• Wire Stripper - 1 No. • Rheostat Wire Wound 38 ohms, 10 A - 1 No.
• Tachometer digital 0 – 9999 rpm - 1 No.
Materials/Components
• D.C. shunt motor 3HP, 220 V, 12 A - 1 No.
• Ammeter (M.C) 0-3A - 1 No. • Connecting wires PVC insulated

Procedure

The speed of a DC shunt motor can be controlled by varying

• Flux/pole (Flux control method)
• Resistance of armature circuit (rheostat control method)
• Applied voltage(Voltage control method) Speed of a motor is given by the relation:
In Armature Control method
N ∞ Eb-IaRa
In field Control method

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