Experiment No. 8
Date: 05.06.2021
Expt. Bed No. B4
V & INVERTED V CURVES OF ALTERNATOR & SYNCHRONOUS MOTOR
Aim of the Experiment: To plot the V and inverted V curves of the alternator and
synchronous motor under constant power output.
Name plate details:
Output power
Rated voltage
Full load current
Speed
Alternator Stator
5 kVA
1.3 A
-
Alternator Rotor
430 V
6.6 A
1500 rpm
Apparatus Required:
1
2
3
4
5
6
Apparatus
DC voltmeter
DC ammeters
AC voltmeter
AC ammeter
Wattmeter
Rheostats
7
8
9
DPST switch
TPST switch
Synchronizing lamp Set
Circuit Diagram:
Rating
0 – 300 V
0 – 2.5 A; 0 – 20 A
0 – 600 V; 0 – 300 V
0 – 10 A
3000 V/10 A, UPF
360 Ω/1.2 A; 500
Ω/1.2 A
-
Nos.
1
1 each
2;1
1
1
1 each
1
1
1
DC Motor
5.2 kW
220 V
28 A
1500 rpm
Test data for V & inverted V curves of Alternator:
Trial
Wattmeter reading W1 = 200 W
Wattmeter reading W2 = 320 W
1
2
3
4
5
6
7
8
9
10
11
Field
current (If)
Amperes
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
1.1
Field
current (If)
Amperes
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
1.1
Armature
current (Ia)
Amperes
5.6
4.5
3.3
2.3
1.4
1.2
0.8
1.2
2.2
2.9
3.8
Power
factor
Armature
current (Ia)
Amperes
6.5
5.2
3.9
4.8
1.8
1.2
1
1.2
1.9
2.8
3.7
Calculation:
𝑷𝒐𝒘𝒆𝒓 𝒇𝒂𝒄𝒕𝒐𝒓 =
𝑾𝒂𝒕𝒕𝒎𝒆𝒕𝒆𝒓 𝒓𝒆𝒂𝒅𝒊𝒏𝒈
𝑽𝒂
× 𝑰𝒂
√𝟑
Plot the V and inverted V curves for the alternator with the recorded readings
Power
factor