The document provides an orientation for experiments to be conducted in the EMEC lab, including testing various electrical machines using different circuits and measurements. Experiments will involve open and short circuit tests on transformers, motors, and generators using equipment mounted on various panels that receive single or three phase AC power as well as DC power sources. Proper safety procedures and experimental methods are outlined.

1. EMEC LAB ORIENTATION
Importance of Electrical M/Cs
Classification of Electrical M/Cs
What do you mean by testing of
Electrical M/Cs?
How do we test them? (According to
BIS, IEC)

3. Experiments to be conducted in
First Cycle
 O. C and S.C Tests on a Single Phase
Transformer
No load tests on a DC shunt motor
( Swinburne’s & Speed Control Test )
No load tests on a Synchronous m/c
(OC and SC test)
No load tests on a DC Shunt
generator( O.C Test & Critical Speed )
Load test on a DC Shunt generator

4. Circuit Diagram Exp 1
50V/10A
0-10A
1A
0-50V
1A
1
A

5. Circuit Diagram
125V/2.5A
0- 2.5A
1A
0-125V
1A

6. 3 phase variac connections
Use any one phase ( R/Y/B ) and neutral of three phase
Variac instead of single phase variac shown in Figs 1.3
and 1.4 for O. C and S. C test.
Keep the variac at it’s minimum position (zero) before
switching on / off the supply mains.

7. Panel Details
Machine Instruments Mounted Fuse Supply Expts to be
Panel Rating on Panel Rating 1 3 DC Conducted
No.
1 Transformer 1.Voltmeter 0- 500V 1A for Yes Variac No 1 6
2KVA, Two ( AC ) OC (3 )
115/230V 2.Ammeter 0-10A; &SC 0-230V
Two ( AC ) Test
3.Wattmeter UPF 2A for
250V/10A –one Sump-
4.Wattmeter LPF ner’s
500V/5A –one test
16 Transformer 1.Voltmeter 0-500V 1A for Yes Variac No 1 6
2KVA, Two ( AC ) OC ( 3 )
115/230V 2.Ammeter 0-10A &SC 0-230V
Three ( AC ) Test
3.Wattmeter UPF
250V/10A –one 2A for
4.Wattmeter LPF Sump-
500V/5A –one ner’s
test

8. Circuit Diagram Exp 2
272Ω/1.7A
0-2A
+ 
90Ω / 5A
+ 
7A 0-5A
+
0-250V

7A
Keep Ra (ext) at it’s maximum value while switching
ON / OFF the DC supply mains
Do not switch OFF the supply mains until the two tests
are over (Swinburne’s & speed control Tests).

9. Circuit Diagram for
measurement of Ra
V
?
Measure Ra at the end only

10. Panel Details
Panel Machine Instruments Fuse Supply Expts to
No. Rating Mounted on Rating be
Panel Conduc-
ted
1 3 DC
19 DC shunt 1.Voltmeter DC 7A Yes No Yes 2
motor, 0-250V -one
220V, 46A, 2.Ammeter 0-10A
9 KW, 1120- one( DC )
1500rpm 2.Ammeter 0-2A -
one( DC )
22 DC shunt 1.Voltmeter DC 7A Yes No Yes 2
motor, 0-250V -one
220V, 2.Ammeter 0-10A –
56.5A, one( DC )
13KW, 2.Ammeter 0-2A –
1400rpm one ( DC )

11. Circuit Diagram Exp 3 Panel No 9
0-15A
80AA
80 0-60Hz
0-60Hz
0-500V
80A 100Ω/2A
80A 100Ω / 2A 0-500V
0-2A
2A
2A + 
676Ω/1.2A
676Ω/1.7A 0-2A
2A
2A
Modification required in exciter circuit for panel 10
( Input at X1 and X2 )

12. Panel No 9
80A
0-15A
80A 100Ω/2A
0-2A
2A
676Ω/1.2A
2A
SC Test
Note: Fuse rating of DC motor is 55A for panel No.10

13. Modified exciter circuit for panel 10
Fig 3.3.A

15. Connection diagram for 4 point starter at panel 10
L
Fig 3.3.B
In SC test draw the table between If v/s Isc

16. Panel Details
Panel Machine Instruments Fuse Supply Expts
No. Rating Mounted on Rating 1 3 DC To be
Panel Condu-
cted
9 Alternator 1.Voltmeter AC 80A Yes Yes Yes 3 8
Coupled with 0-500V –one
DC shunt Gen 2.Ammeter AC
Alternator: 0-20A -one
10KVA, 440V, 3.Freq meter
1000rpm, 0-60Hz -one
13.2A 4. Voltmeter DC
50Hz, 3, 0-250V -one
0.8pf 5. Ammeter DC
Excit. Volts 0-15A -one
220V 6. Ammeter DC
Excit. Amps 0-2A -one
2A (3 point Starter)
DC Motor-
20BHP, 220V,
950rpm,79.8A

17. Panel Details
10 Synchronous 1.Voltmeter AC 55A Yes Yes Yes 3 8
M/C 3 0-500V –one
Motor,  /, 2.Ammeter AC
231V/400V, 0-25A -one 21V
39/22.5A, 11KW, (ANALOG to be 25A
0.82,pf, 1450 rpm connected) for
3 motor, /, 3.Freq meter Exciter
231V/400V, 0-60Hz -one
22/12.7A,7.5KW 4. Voltmeter DC
UPF, 1450rpm 0-250V -one
3, 5. Ammeter DC
Generator,, 0-20A -one
400V,10.8A, 6. Ammeter DC
7.5KVA,0.8pf, 0-10A -one
1500rpm,50c/s. (4point Starter)
Excit.21V Synchroscope-one
DC motor, 220V,
52.5A, 10KW,
1500rpm
DC Generator,
175V, 57A,
10KW,1450rpm

18. Circuit Diagram ( OCC) Panel No 2
100Ω /5A
7A
272Ω /1.7A
0-250V
7A
0-2A
2A
272Ω /1.7A
2A
Note: For Panel number 5 Voltmeter range is 0-300V
Fig 4.1

19. Circuit Diagram ( Critical Speed )
Panel No 2
100Ω /5A
5A
a
272Ω /1.7A 272Ω/1.7A
0-250 V
0-2A
5A A
Note: Generator side FR is 570Ω/1.2A
Fig 4.2 for panel No 5
Add one more double barrel rheostat in series with Ra
(ext) to bring down the motor speed to nearly 300 rpm in
the circuit diagram (Fig 4.2 of Lab manual)
Connect an 0-2 A DC ammeter in generator field circuit
(not shown in manual)

20. Panel Details
Machine Instruments Fuse Supply Expts to be
Panel Rating mounted on Rating conducted
No. Panel 1 3 DC
2 DC motor 1.Voltmeter DC 5A Yes No Yes 4
Generator set 0-250V –one
(coupled) 2.Ammeter DC
Motor-230V, 0-2A -one
28A, 5.5KW,
1450 rpm
Generator-
160V, 29A,
4.65KW
1450rpm
5 DC motor 1.Voltmeter DC 5A Yes No Yes 4
Generator set 0-250V –one
(coupled) 2.Ammeter DC
Motor-220V, 0-2A -one
20.3A,5H.P, (3point starter,
1450 rpm not to be
Gen- 220V, used)
11.8A, 2.6KW
1450rpm

21. Circuit Diagram (Load test on DC Gen. )
Panel No. 6
15A 0-15A
15A
0-2A
0-250V
280Ω /1.8A
272Ω /1.7A
0-250V
15A 15A
Note: For panel No4 take 25A in place of 15A at all points
Fig 5.1
At panel 4 use four point starter (as shown in Fig 3.3.B)
At panel 4 connect a additional loading unit if required
NOTE: Ammeter on source-side of motor not required.

22. Panel Details
Panel Machine Instruments Fuse Supply Expts
No. Rating Mounted on Rating to be
Panel 1 3 DC Condu
cted
4 DC motor gen 1 Voltmeter DC 21A Yes No Yes 5 7
set (coupled) 0-500V –one
Motor-220V, 2. Ammeter DC
21A,3.8KW, 0-20A -two
5.2H.P,1070- 3. Ammeter DC
1450rpm 0-2A -two
Gen-230V, (4 point starter)
20.8A,4.8KW
1450 rpm
6 DC motor gen 1 Voltmeter DC 15A Yes No Yes 5 7
set (identical) 0-500V –one
220V, 12.8A, 2. Ammeter DC
2.2KW, 3 HP, 0-20A -two
1450 rpm 3. Ammeter DC
0-2A -two
(3 point starter)

23. Some Questions Related to every
Experiment
 Objective
 Instruments Used
 Supply [AC (1 or 3 Phase) or DC or Both]
 Machines
You are supposed to come prepared for expts,
the circuit diagram given in manual must be
labeled properly

24. Every Batch will submit a lab
report containing the following
1) Aim of the experiment
2) Observation Table
3) Calculations/graph
4) Comments on results & precautions
5) Draw the Neat Labeled Physical
Layout after the each Experiment.

25. Some Rule and Regulation of this Lab
 Be punctual
 Always wear shoes with rubber sole
 Do not wear lose clothes
 DO not touch any live terminals or wires
 Beware of dynamics of machinery and consciously
keep a distance
 Before switching on the supply make sure that there is
NO LOOSE CONNECTION and get your connections
approved by the instructor
 After completing the experiment, disconnect the circuit
and keep the wires at the proper place

26. Connection diagram for 4 point starter
L
Fig 3.3 B

27. • Note: 1. Mark the DC Machines /
Instruments with proper polarity.
2. DC Machines on panel number
4 and 10 have four point starter.