Procedure
1. Connect the induction motor (slip ring) as shown below.
CIRCUIT DIAGRAM
L1
I*
A
RUN
D
I
START
A1
E
V
F
R
S
T
B1
C1
STATOR
ROTOR
L2
L3
2. Connect the set up as in the connection diagram below.
CONNECTION DIAGRAM ACM 101 FOR BENCH NO. 7
L1
L2
T1
D
A
T2
E
B
F
C
A
B
C
AC WOUND ROTOR INDUCTION MOTOR
L3
STATOR
Power
Analyser
D
E
ROTOR
F
T2
AC SALIENT POLE ALTERNATOR
T1
L
DC
110V
N
BENCH SUPPLY NO. 7
L1
L2
L3
N
AC 240V,3ø
3. Load the motor by means of the brake disc from no load to full load (8.5A) in steps of 0.5A
and record the instrument readings.
4. Plot curves of speed, efficiency, current, torque, power factor, and slip against output power
on the same axis.
5. Plot a curve of line current against torque.
NB:
 Make sure that the motor is rotating clockwise looking from the disk brake.
 The reading on the force balance gives the force in newtons, but not the torque hence measures
the distance from the center of the machine shaft and the center of the last hole on the balance.
 The product of the force indicated and the distance in meters will give the torque (Nm)
 Use tachometer for speed measurements
 At higher values of load current taking the reading very quickly.
OBSERVATIONS
𝑽𝑳
Increasing load caused the speed to reduce.
Current gradually increased as more load was added
Table results are as follows:
𝑰𝑳
INPUT
TORQUE (N-m)
POWER FORCE DIST
(kW)
(N)
(M)
SPEED
[RPM]
OUTPUT EFFICIENCY P. F SLIP
POWER (%)
(kW)
234.9 5.35 1.257
0
0.225
1481
0.334
26.8
0.22
242.6 6.00 1.456
23
0.225
1475
0.880
60.4
0.52
243.7 6.55 1.596
31
0.225
1460
1.090
68.5
0.61
242.6 7.07 1.715
40
0.225
1457
1.300
75.8
0.67
242.5 7.49 1.816
46
0.225
1450
1.400
77.1
0.69
241.3 8.00 1.930
51
0.225
1445
1.610
83.4
0.73
241.0 8.43 2.031
54
0.225
1440
1.620
79.8
0.73
Analysis
Input power 𝑷 = 𝑽𝑰 as shown in the table
Efficiency of the motor =
𝒐𝒖𝒕𝒑𝒖𝒕 𝒑𝒐𝒘𝒆𝒓
𝒊𝒏𝒑𝒖𝒕 𝒑𝒐𝒘𝒆𝒓
i.e., the efficiency when the motor at 5.35A load =
𝟎.𝟑𝟑𝟒𝐤𝐰
𝟐𝟒𝟑.𝟗∗𝟓.𝟑𝟓
= 0.25
Current (IL)
Torque (N-m)
14
12
10
8
6
4
2
0
-2 0
2
4
6
8
9
8
7
6
5
4
3
2
1
0
0
10
0,5
Line Current
1490
Effeciency (%)
1470
1460
1450
1440
1430
0,5
1
1,5
2
1,5
90
80
70
60
50
40
30
20
10
0
0
2
0,5
1
1,5
2
Output Power (kW)
Output Power (kW)
14
12
Torque (N-m)
Speed (rpm)
1480
0
1
Output Power (kW)
10
8
6
4
2
0
0
0,2
0,4
0,6
0,8
1
Output Power (kW)
1,2
1,4
1,6
1,8