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)
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
Circuit Diagram Exp 1
1
A
1A
1A
0-50V
50V/10A
0-10A
Circuit Diagram
1A
1A
125V/2.5A
0- 2.5A
0-125V
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.
3 phase variac connections
Panel Details
Panel
No.
Machine
Rating
Instruments Mounted
on Panel
Fuse
Rating
Supply Expts to be
Conducted1 3 DC
1 Transformer
2KVA,
115/230V
1.Voltmeter 0- 500V
Two ( AC )
2.Ammeter 0-10A;
Two ( AC )
3.Wattmeter UPF
250V/10A –one
4.Wattmeter LPF
500V/5A –one
1A for
OC
&SC
Test
2A for
Sump-
ner’s
test
Yes Variac
(3 )
0-230V
No 1 6
16 Transformer
2KVA,
115/230V
1.Voltmeter 0-500V
Two ( AC )
2.Ammeter 0-10A
Three ( AC )
3.Wattmeter UPF
250V/10A –one
4.Wattmeter LPF
500V/5A –one
1A for
OC
&SC
Test
2A for
Sump-
ner’s
test
Yes Variac
( 3 )
0-230V
No 1 6
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).
Circuit Diagram Exp 2
7A
7A
272Ω/1.7A0-2A
0-5A
0-250V
90Ω / 5A
+
+
+
Measure Ra at the end only
?
Circuit Diagram for
measurement of Ra
V
Panel
No.
Machine
Rating
Instruments
Mounted on
Panel
Fuse
Rating
Supply Expts to
be
Conduc-
ted
1 3 DC
19 DC shunt
motor,
220V, 46A,
9 KW, 1120-
1500rpm
1.Voltmeter DC
0-250V -one
2.Ammeter 0-10A
one( DC )
2.Ammeter 0-2A -
one( DC )
7A Yes No Yes 2
22 DC shunt
motor,
220V,
56.5A,
13KW,
1400rpm
1.Voltmeter DC
0-250V -one
2.Ammeter 0-10A –
one( DC )
2.Ammeter 0-2A –
one ( DC )
7A Yes No Yes 2
Panel Details
Circuit Diagram Exp 3
Modification required in exciter circuit for panel 10
( Input at X1 and X2 )
80 A
80A 100Ω/2A
2A
2A676Ω/1.7A 0-2A
0-60Hz
0-500V
0-15A
Panel No 9
+
80A
80A100Ω / 2A
2A
2A
0-2A
676Ω/1.2A
0-60Hz
0-500V
SC Test
Panel No 9
80A
80A
2A
2A
0-2A
676Ω/1.2A
100Ω/2A
0-15A
Note: Fuse rating of DC motor is 55A for panel No.10
Modified exciter circuit for panel 10
Fig 3.3.A
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
Panel
No.
Machine
Rating
Instruments
Mounted on
Panel
Fuse
Rating
Supply Expts
To be
Condu-
cted
1 3 DC
9 Alternator
Coupled with
DC shunt Gen
Alternator:
10KVA, 440V,
1000rpm,
13.2A
50Hz, 3,
0.8pf
Excit. Volts
220V
Excit. Amps
2A
DC Motor-
20BHP, 220V,
950rpm,79.8A
1.Voltmeter AC
0-500V –one
2.Ammeter AC
0-20A -one
3.Freq meter
0-60Hz -one
4. Voltmeter DC
0-250V -one
5. Ammeter DC
0-15A -one
6. Ammeter DC
0-2A -one
(3 point Starter)
80A Yes Yes Yes 3 8
Panel Details
10 Synchronous
M/C 3
Motor, /,
231V/400V,
39/22.5A, 11KW,
0.82,pf, 1450 rpm
3 motor, /,
231V/400V,
22/12.7A,7.5KW
UPF, 1450rpm
3,
Generator,,
400V,10.8A,
7.5KVA,0.8pf,
1500rpm,50c/s.
Excit.21V
DC motor, 220V,
52.5A, 10KW,
1500rpm
DC Generator,
175V, 57A,
10KW,1450rpm
1.Voltmeter AC
0-500V –one
2.Ammeter AC
0-25A -one
(ANALOG to be
connected)
3.Freq meter
0-60Hz -one
4. Voltmeter DC
0-250V -one
5. Ammeter DC
0-20A -one
6. Ammeter DC
0-10A -one
(4point Starter)
Synchroscope-one
55A Yes Yes Yes
21V
25A
for
Exciter
3 8
Panel Details
Circuit Diagram ( OCC)
Fig 4.1
7A
7A
272Ω /1.7A
100Ω /5A
2A
2A272Ω /1.7A
0-2A
0-250V
Panel No 2
Note: For Panel number 5 Voltmeter range is 0-300V
Circuit Diagram ( Critical Speed )
Fig 4.2
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 DCammeter in generator field circuit
(not shown in manual)
A
5A
5A
272Ω /1.7A
100Ω /5A
272Ω/1.7A
0-250 V
0-2A
Panel No 2
Note: Generator side FR is 570Ω/1.2A
for panel No 5
a
Panel
No.
Machine
Rating
Instruments
mounted on
Panel
Fuse
Rating
Supply Expts to be
conducted
1 3 DC
2 DC motor
Generator set
(coupled)
Motor-230V,
28A, 5.5KW,
1450 rpm
Generator-
160V, 29A,
4.65KW
1450rpm
1.Voltmeter DC
0-250V –one
2.Ammeter DC
0-2A -one
5A Yes No Yes 4
5 DC motor
Generator set
(coupled)
Motor-220V,
20.3A,5H.P,
1450 rpm
Gen- 220V,
11.8A, 2.6KW
1450rpm
1.Voltmeter DC
0-250V –one
2.Ammeter DC
0-2A -one
(3point starter,
not to be
used)
5A Yes No Yes 4
Panel Details
Circuit Diagram (Load test on DC Gen. )
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.
15A
15A0-250V
0-15A15A
15A
0-250V
0-2A
272Ω /1.7A
Note: For panel No4 take 25A in place of 15A at all points
280Ω /1.8A
Panel No. 6
Panel
No.
Machine
Rating
Instruments
Mounted on
Panel
Fuse
Rating
Supply Expts
to be
Condu
cted1 3 DC
4 DC motor gen
set (coupled)
Motor-220V,
21A,3.8KW,
5.2H.P,1070-
1450rpm
Gen-230V,
20.8A,4.8KW
1450 rpm
1 Voltmeter DC
0-500V –one
2. Ammeter DC
0-20A -two
3. Ammeter DC
0-2A -two
(4 point starter)
21A Yes No Yes 5 7
6 DC motor gen
set (identical)
220V, 12.8A,
2.2KW, 3 HP,
1450 rpm
1 Voltmeter DC
0-500V –one
2. Ammeter DC
0-20A -two
3. Ammeter DC
0-2A -two
(3 point starter)
15A Yes No Yes 5 7
Panel Details
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
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.
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
Connection diagram for 4 point starter
Fig 3.3 B
L
• Note: 1. Mark the DC Machines /
Instruments with proper polarity.
2. DC Machines on panel number
4 and 10 have four point starter.