08-05-2012, 04:36 PM
LOAD TEST ON THREE PHASE SQUIRREL CAGE INDUCTION MOTOR
51355420-LAB-MANUAL-FOR-E-E-CS.pdf (Size: 523.09 KB / Downloads: 113)
FORMULAE USED
1.Torque = (S1-S2) (R+t/2) x 9.81 N-m
Where, S1, S2 – spring balance readings in Kg.
R - Radius of brake drum in m.
t - Thickness of belt in m.
2. Output Power = 2 pNT/60 watts.
N- Rotor speed in rpm.
T- Torque in N-m.
PROCEDURE:
• Connections are given as per the circuit diagram.
• The TPSTS is closed and the motor is started using On Line starter to run at rated speed.
• At no load the speed, current, voltage and power are noted down.
• By applying the load for various values of current the above-mentioned readings are noted.
• The load is later released and the motor is switched off and the graph is drawn. .
GRAPH
The graph are drawn as
• Output Power Vs Speed
• Output Power Vs Line current
• Output Power Vs Torque
• Output Power Vs Power factor
• Output Power Vs % Efficiency
• Output Power Vs % Slip.