This document discusses tests that can be performed to determine the circuit parameters of an induction motor. It describes three main tests: 1) The DC test, which applies a DC voltage to determine the stator resistance and can be used on both wye- and delta-connected staters. 2) The blocked-rotor test, which applies an AC voltage with the rotor blocked to determine the magnetizing reactance and resistance parameters. 3) The no-load test, where the rotor is unblocked and allowed to run without load, which determines the magnetizing reactance and combined core losses. Diagrams of equivalent circuits are provided to analyze the test results.

1. OF
BANGLADESH
ECE 441 1

2. SELF INTRODUCESELF INTRODUCE
Supervised bySupervised by
……………
Advisor
Dept. of EEE
Name:
ID:……..
Dept. of EEE

3. PRESENTATIONPRESENTATION
ONON
TESTS TO DETERMINE CKT PARAMETER OF INDUCTION
MOTOR
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4. •DC Test
• Determines R1
• Connect any two stator leads to a variable-
voltage DC power supply
• Adjust the power supply to provide rated stator
current
• Determine the resistance from the voltmeter
and ammeter readings
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4

5. DC
DC
DC
V
R
I
=
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6. FOR A Y-CONNECTED STATOR
1,
1,
2
2
DC wye
DC
wye
R R
R
R
=
=
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7. FOR A DELTA-CONNECTED
STATOR
1 1
1
1 1
1
2 2
2 3
1.5
DC
DC
R R
R R
R R
R R
∆ ∆
∆
∆ ∆
∆
×
= =
+
=
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8. •Blocked-Rotor Test
• Determine X1 and X2
• Determines R2 when combined with data from
the DC Test
• Block the rotor so that it will not turn
• Connect to a variable-voltage AC supply and
adjust until the blocked-rotor current is equal to
the rated current
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10. SIMPLIFIED EQUIVALENT
CIRCUIT
Neglect the exciting current under blocked-rotor
conditions – remove the parallel branch
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11. •No-Load Test
• Determine the magnetizing reactance, XM
and combined core, friction, and wind age
losses.
• Connect as for blocked-rotor test (next
slide).
• The rotor is unblocked and allowed to run
unloaded at rated voltage and rated
frequency.

12. Electrical connection for the No-Load
Test is the same as for the Blocked-
Rotor Test
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13. •At no-load, the speed is very close to
synchronous speed – the slip is =0, causing
the current in R2/s to be very small, and will
be ignored i the calculations.
•IM>>Ife, so I0 = IM.
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14. THANKS TO ALLTHANKS TO ALL
ECE 441 14
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