Electrical Engineering Lab Manual For Ii Mech Part I 3p5c6g
This document was ed by and they confirmed that they have the permission to share it. If you are author or own the copyright of this book, please report to us by using this report form. Report r6l17
Overview 4q3b3c
& View Electrical Engineering Lab Manual For Ii Mech Part I as PDF for free.
More details 26j3b
- Words: 3,176
- Pages: 54
VELS UNIVERSITY School of Engineering
DEPARTMENT OF EEE LAB MANUAL CLASS SEMESTER SUBJECT CODE SUBJECT
: II YEAR MECH : III SEM : : Electrical Engineering Lab
S No 1
Name of the Experiment
2 3
Speed control of DC shunt motor (Armature, Field control)
4
Load test on single phase transformer
5
O.C & S.C Test on a single phase transformer
6
Regulation of an alternator by EMF & MMF methods.
7
V curves and inverted V curves of synchronous Motor
9 10 11
Date of
Experiment
submission
Load test on DC Shunt & DC Series motor O.C.C & Load characteristics of Separately excited and Self excited DC generator
8
Date of
Load test on three phase squirrel cage Induction motor Speed control of three phase slip ring Induction Motor Load test on single phase Induction Motor. Study of DC & AC Starters
Ex.No.1 a) LOAD TEST ON DC SHUNT MOTOR
Marks
Sign
AIM: To conduct load test on DC shunt motor and to find efficiency. APPARATUS REQUIRED: S.No. 1 2 3 4 5
Apparatus Ammeter Voltmeter Rheostat Tachometer Connecting Wires
Range (0-20)A (0-300)V 1250Ω , 0.8A (0-1500) rpm 2.5sq.mm.
Type MC MC Wire Wound Digital Copper
Quantity 1 1 1 1 Few
PRECAUTIONS: 1. DC shunt motor should be started and stopped under no load condition. 2. Field rheostat should be kept in the minimum position. 3. Brake drum should be cooled with water when it is under load.
PROCEDURE: 1. Connections are made as per the circuit diagram. 2. After checking the no load condition, and minimum field rheostat position, DPST switch is closed and starter resistance is gradually removed.
3. The motor is brought to its rated speed by adjusting the field rheostat. 4. Ammeter, Voltmeter readings, speed and spring balance readings are noted under no load condition. 5. The load is then added to the motor gradually and for each load, voltmeter, ammeter, spring balance readings and speed of the motor are noted. 6. The motor is then brought to no load condition and field rheostat to minimum position, then DPST switch is opened.
TABULAR COLUMN:
S.No.
Voltage V (Volts)
Current I (Amps)
Spring Balance Reading S1(Kg)
S2(Kg)
Circumference of the Brake drum
(S1∼ S2)Kg
=
Speed N (rpm)
Torque T (Nm)
cm.
Output Power Pm (Watts)
Input Power Pi (Watts)
Efficiency η %
FORMULAE: Circumference R
=
------------------- m 100 x2π
Torque T = (S1 ∼ S2) x R x 9.81 Nm
Input Power Pi = VI Watts 2π NT Output Power Pm = ------------ Watts 60 Output Power Efficiency η %
= -------------------- x 100% Input Power
Speed N (rpm)
y2
Speed N (rpm)
y3
Torque T (Nm)
Efficiency %
MODEL GRAPHS:
y1
N
y
η
T x Torque T (Nm)
Output Power (Watts)
RESULT: Thus load test on DC shunt motor is conducted and its efficiency is determined.
Ex.No.1 b) LOAD TEST ON DC SERIES MOTOR AIM: To conduct load test on DC Series Motor and to find efficiency. APPARATUS REQUIRED: S.No. 1 2
Apparatus Ammeter Voltmeter
3
Tachometer
4
Connecting Wires
Range (0-20)A (0-300)V (0-3000) rpm 2.5sq.mm.
PRECAUTIONS: 1. The motor should be started and stopped with load 2. Brake drum should be cooled with water when it is under load.
Type MC MC
Quantity 1 1
Digital
1
Copper
Few
PROCEDURE: 1. Connections are made as per the circuit diagram. 2. After checking the load condition, DPST switch is closed and starter resistance is gradually removed. 3. For various loads, Voltmeter, Ammeter readings, speed and spring balance readings are noted. 4. After bringing the load to initial position, DPST switch is opened.
TABULAR COLUMN:
S.No.
Voltage V (Volts)
Current I (Amps)
Spring Balance Reading S1(Kg)
S2(Kg)
(S1∼ S2)Kg
Speed N (rpm)
Torque T (Nm)
Output Power Pm (Watts)
Input Power Pi (Watts)
Efficiency η %
FORMULAE: Circumference R
=
------------------- m 100 x2π
Torque T = (S1 ∼ S2) x R x 9.81 Nm Input Power Pi = VI Watts 2π NT Output Power Pm = ------------ Watts 60 Output Power Efficiency η %
= -------------------- x 100% Input Power
y2
Speed N (rpm)
y3
Torque T (Nm)
Efficiency %
MODEL GRAPH:
y1 T E
N RESULT: Thus load test on DC series motor is conducted and its efficiency is determined. Output Power (Watts)
Ex.No.2 a) OPEN CIRCUIT CHARACTERISTICS OF SEPARATELY EXCITED DC SHUNT GENERATOR AIM: To obtain open circuit characteristics of separately excited DC shunt generator. APPARATUS REQUIRED: S.No. 1 2 3 4 5
Apparatus Ammeter Voltmeter Rheostats Tachometer Connecting Wires
Range (0-1)A (0-300)V 1250Ω , 0.8A (0-1500)rpm 2.5sq.mm.
Type MC MC Wire Wound Digital Copper
Quantity 1 1 2 1 Few
PRECAUTIONS: 1. The field rheostat of motor should be in minimum resistance position at the time of starting and stopping the machine. 2. The field rheostat of generator should be in maximum resistance position at the time of starting and stopping the machine.
PROCEDURE: 1. Connections are made as per the circuit diagram. 2. After checking minimum position of motor field rheostat, maximum position of generator field rheostat, DPST switch is closed and starting resistance is gradually removed. 3. By adjusting the field rheostat, the motor is brought to rated speed. 4. By varying the generator field rheostat, voltmeter and ammeter readings are taken. 5. After bringing the generator rheostat to maximum position, field rheostat of motor to minimum position, DPST switch is opened.
TABULAR COLUMN: S.No.
Eo (Volts)
MODEL GRAPH:
If (Amps)
Field Current
Armature Voltage
If (Amps)
Eo (Volts)
RESULT: Thus open circuit characteristics of separately excited DC shunt generator is obtained.
Ex.No.2 b) LOAD CHARACTERISTICS OF SEPARATELY EXCITED DC SHUNT GENERATOR AIM: To obtain internal and external characteristics of DC separately excited DC shunt generator. APPARATUS REQUIRED: S.No.
Apparatus
1
Ammeter
2 3 4 5 6
Voltmeter Rheostats Loading Rheostat Tachometer Connecting Wires
Range (0-2)A
Type MC
Quantity 1
(0-20) A (0-300)V 1200Ω , 0.8A 5KW, 230V (0-1500)rpm 2.5sq.mm.
MC MC Wire Wound Digital Copper
1 1 2 1 1 Few
PRECAUTIONS: 1. The field rheostat of motor should be at minimum position. 2. The field rheostat of generator should be at maximum position. 3. No load should be connected to generator at the time of starting and stopping. PROCEDURE: 1. Connections are made as per the circuit diagram.
2. After checking minimum position of DC shunt motor field rheostat and maximum position of DC shunt generator field rheostat, DPST switch is closed and starting resistance is gradually removed. 3. Under no load condition, Ammeter and Voltmeter readings are noted, after bringing the voltage to rated voltage by adjusting the field rheostat of generator. 4. Load is varied gradually and for each load, voltmeter and ammeter readings are noted. 5. Then the generator is unloaded and the field rheostat of DC shunt generator is brought to maximum position and the field rheostat of DC shunt motor to minimum position, DPST switch is opened.
DETERMINATION OF ARMATURE RESISTANCE:
Fuse
+
27A
220V DC Supply
D P S T S W I T C H
-
+
A
-
(0-20)A MC A1
+ V
G
LOAD 5 KW, 230V 27A Fuse
PROCEDURE: 1. Connections are made as per the circuit diagram. 2. Supply is given by closing the DPST switch. 3. Readings of Ammeter and Voltmeter are noted. 4. Armature resistance in Ohms is calculated as Ra = (Vx1.5) /I
TABULAR COLUMN:
A2
(0-300)V MC
S.No.
Voltage
Current
Armature Resistance
V (Volts)
I (Amps)
Ra (Ohms)
TABULAR COLUMN:
S.No.
Field
Load
Terminal
Current
Current
Voltage
If (Amps)
IL (Amps)
(V) Volts
FORMULAE: Eg
=
V + Ia Ra (Volts)
Ia
=
IL + If (Amps)
Ia = IL + If (Amps)
Eg =V + Ia Ra (Volts)
Eg
:
Generated emf in Volts
V
:
Terminal Voltage in Volts
Ia
:
Armature Current in Amps
IL
:
Line Current in Amps
If
:
Field Current in Amps
Ra
:
Armature Resistance in Ohms
VL, E (Volts)
MODEL GRAPH:
E Vs IL (Int Char) V Vs IL (Ext Char) RESULT: Thus load characteristics of separately excited DC shunt generator is obtained.
Ex.No.2 c)
If, IL (Amps)
OPEN CIRCUIT CHARACTERISTICS OF SELF EXCITED
DC SHUNT GENERATOR AIM: To obtain open circuit characteristics of self excited DC shunt generator and to find its critical resistance. APPARATUS REQUIRED: S.No. 1 2 3 4 5 6
Apparatus Ammeter Voltmeter Rheostats SPST Switch Tachometer Connecting Wires
Range (0-1)A (0-300)V 1250Ω , 0.8A (0-1500)rpm 2.5sq.mm.
Type MC MC Wire Wound Digital Copper
Quantity 1 1 2 1 1 Few
PRECAUTIONS: 1. The field rheostat of motor should be in minimum resistance position at the time of starting and stopping the machine. 2. The field rheostat of generator should be in maximum resistance position at the time of starting and stopping the machine. 3. SPST switch is kept open during starting and stopping.
PROCEDURE: 1. Connections are made as per the circuit diagram. 2. After checking minimum position of motor field rheostat, maximum position of generator field rheostat, DPST switch is closed and starting resistance is gradually removed.
3. By adjusting the field rheostat, the motor is brought to rated speed. 4. Voltmeter and ammeter readings are taken when the SPST switch is kept open. 5. After closing the SPST switch, by varying the generator field rheostat, voltmeter and ammeter readings are taken. 6. After bringing the generator rheostat to maximum position, field rheostat of motor to minimum position, SPST switch is opened and DPST switch is opened.
TABULAR COLUMN: S.N o.
Field
Armature
Current
Voltage
If (Amps)
Eo (Volts)
Eo (Volts)
MODEL GRAPH:
Critical Resistance = Eo / If Ohms
If RESULT:
Eo
Thus open circuit characteristics of self excited DC shunt generator are obtained and its critical resistance is determined. If (Amps)
Ex.No.2 d) LOAD CHARACTERISTICS OF SELF EXCITED DC SHUNT GENERATOR AIM: To obtain internal and external characteristics of DC shunt generator. APPARATUS REQUIRED: S.No.
Apparatus
1
Ammeter
2 3 4 5 6
Voltmeter Rheostats Loading Rheostat Tachometer Connecting Wires
Range (0-2)A
Type MC
Quantity 1
(0-20) A (0-300)V 1200Ω , 0.8A 5KW, 230V (0-1500)rpm 2.5sq.mm.
MC MC Wire Wound Digital Copper
1 1 2 1 1 Few
PRECAUTIONS: 1. The field rheostat of motor should be at minimum position. 2. The field rheostat of generator should be at maximum position. 3. No load should be connected to generator at the time of starting and stopping. PROCEDURE: 1. Connections are made as per the circuit diagram.
2. After checking minimum position of DC shunt motor field rheostat and maximum position of DC shunt generator field rheostat, DPST switch is closed and starting resistance is gradually removed. 3. Under no load condition, Ammeter and Voltmeter readings are noted, after bringing the voltage to rated voltage by adjusting the field rheostat of generator. 4. Load is varied gradually and for each load, voltmeter and ammeter readings are noted. 5. Then the generator is unloaded and the field rheostat of DC shunt generator is brought to maximum position and the field rheostat of DC shunt motor to minimum position, DPST switch is opened.
DETERMINATION OF ARMATURE RESISTANCE:
Fuse
+
27A
220V DC Supply
D P S T S W I T C H
-
+
A
-
(0-20)A MC A1
+ V
G
LOAD 5 KW, 230V 27A Fuse
PROCEDURE: 1. Connections are made as per the circuit diagram. 2. Supply is given by closing the DPST switch. 3. Readings of Ammeter and Voltmeter are noted. 4. Armature resistance in Ohms is calculated as Ra = (Vx1.5) /I
A2
(0-300)V MC
TABULAR COLUMN: S.No.
Voltage
Current
Armature Resistance
V (Volts)
I (Amps)
Ra (Ohms)
TABULAR COLUMN:
S.No.
Field
Load
Terminal
Current
Current
Voltage
If (Amps)
IL (Amps)
(V) Volts
FORMULAE:
Ia = IL + If (Amps)
Eg =V + Ia Ra (Volts)
Eg
=
V + Ia Ra (Volts)
Ia
=
IL + If (Amps)
Eg
:
Generated emf in Volts
V
:
Terminal Voltage in Volts
Ia
:
Armature Current in Amps
IL
:
Line Current in Amps
If
:
Field Current in Amps
Ra
:
Armature Resistance in Ohms
VL, E (Volts)
MODEL GRAPH:
E Vs IL (Int Char) V Vs IL (Ext Char) RESULT: Thus the load characteristicsIof excited DC shunt generator is obtained. , I self (Amps) f
L
Ex.No. 3 SPEED CONTROL OF DC SHUNT MOTOR AIM: To obtain speed control of DC shunt motor by a. Varying armature voltage with field current constant. b. Varying field current with armature voltage constant APPARATUS REQUIRED: S.No. 1 2
Apparatus Ammeter Voltmeter
3
Rheostats
4 5
Tachometer Connecting Wires
Range (0-20) A (0-300) V 1250Ω , 0.8A
Type MC MC Wire
50Ω , 3.5A (0-3000) rpm 2.5sq.mm.
Wound Digital Copper
Quantity 1 1 Each 1 1 Few
PRECAUTIONS: 1. Field Rheostat should be kept in the minimum resistance position at the time of starting and stopping the motor. 2. Armature Rheostat should be kept in the maximum resistance position at the time of starting and stopping the motor.
PROCEDURE: 1. Connections are made as per the circuit diagram. 2. After checking the maximum position of armature rheostat and minimum position of field rheostat, DPST switch is closed
(i) Armature Control: 1. Field current is fixed to various values and for each fixed value, by varying the armature rheostat, speed is noted for various voltages across the armature. (ii) Field Control: 1. Armature voltage is fixed to various values and for each fixed value, by adjusting the field rheostat, speed is noted for various field currents. 2. Bringing field rheostat to minimum position and armature rheostat to maximum position DPST switch is opened.
TABULAR COLUMN: (i) Armature Voltage Control:
S.No.
If1 = Armature Voltage
Speed
If2 = Armature
N (rpm)
Voltage
Va ( Volts)
Speed
If3 = Armature
Speed
N (rpm)
Voltage
N (rpm)
Va ( Volts)
Va ( Volts)
Va2 = Field
Va3 = Field
(ii) Field Control: Va1 = Field S.No.
Speed
Current
N (rpm)
If (A)
If1
MODEL GRAPHS:
N (rpm)
Current If (A)
Speed N (rpm)
Speed N (rpm)
If (A)
Current
Speed
If2 If3
Va1 Va3 Va2
Va (Volts)
If (Amps)
Speed N (rpm)
RESULT: Thus the speed control of DC Shunt Motor is obtained using Armature and Field control methods.
Ex.No. 4
LOAD TEST ON A SINGLE PHASE TRANSFORMER AIM: To conduct load test on single phase transformer and to find efficiency and percentage regulation. APPARATUS REQUIRED: S.No.
Apparatus
1
Ammeter
2
Voltmeter
3
Wattmeter
4
Auto Transformer
5
Resistive Load
6
Connecting Wires
Range (0-10)A
Type MI
Quantity 1
(0-5) A (0-150)V
MI MI
1 1
(0-300) V (300V, 5A)
MI Upf
1 1
(150V, 5A) 1φ , (0-
Upf
1
-
1
-
1
Copper
Few
260)V 5KW, 230V 2.5sq.mm
PRECAUTIONS: 1. Auto Transformer should be in minimum position. 2. The AC supply is given and removed from the transformer under no load condition. PROCEDURE: 1. Connections are made as per the circuit diagram.
2. After checking the no load condition, minimum position of auto transformer and DPST switch is closed. 3. Ammeter, Voltmeter and Wattmeter readings on both primary side and secondary side are noted. 4. The load is increased and for each load, Voltmeter, Ammeter and Wattmeter readings on both primary and secondary sides are noted. 5. Again no load condition is obtained and DPST switch is opened.
TABULAR COLUMN:
S.No.
Load
V1 (Volts)
Primary I1 (Amps)
W1 (Watts)
Secondary V2 I2 W2 (Volts) (Amps) (Watts)
Input Power W1 x MF
Output Power W2 x MF
Efficiency η %
% Regulation
FORMULAE: Output Power = W2 x Multiplication factor Input Power = W1 x Multiplication factor Output Power Efficiency η %
= -------------------- x 100% Input Power VNL - VFL (Secondary)
Regulation R % = ------------------------------ x 100% VNL
Regulation R %
Efficiency η %
MODEL GRAPHS:
η R
RESULT: Thus the load test on single phase transformer is conducted.
Output Power (Watts)
Ex.No. 13 OPEN CIRCUIT & SHORT CIRCUIT TEST ON A SINGLE PHASE TRANSFORMER AIM: To predetermine the efficiency and regulation of a transformer by conducting open circuit test and short circuit test and to draw equivalent circuit. APPARATUS REQUIRED: S.No.
Apparatus
1
Ammeter
2
Voltmeter
3
Wattmeter
4
Connecting Wires
Range (0-2)A
Type MI
Quantity 1
(0-5) A (0-150)V (150V, 5A)
MI MI LPF
1 2 1
(150V, 5A) 2.5sq.mm
UPF Copper
1 Few
PRECAUTIONS: 1. Auto Transformer should be in minimum voltage position at the time of closing & opening DPST Switch.
PROCEDURE: OPEN CIRCUIT TEST:
1. Connections are made as per the circuit diagram. 2. After checking the minimum position of Autotransformer, DPST switch is closed. 3. Auto transformer variac is adjusted get the rated primary voltage. 4. Voltmeter, Ammeter and Wattmeter readings on primary side are noted. 5. Auto transformer is again brought to minimum position and DPST switch is opened. SHORT CIRCUIT TEST: 1. Connections are made as per the circuit diagram. 2. After checking the minimum position of Autotransformer, DPST switch is closed. 3. Auto transformer variac is adjusted get the rated primary current. 4. Voltmeter, Ammeter and Wattmeter readings on primary side are noted. 5. Auto transformer is again brought to minimum position and DPST switch is opened.
TABULAR COLUMN: OPEN CIRCUIT TEST: Vo
Io
Wo
(Volts)
(Amps)
(Watts)
Vsc
Isc
Wsc
(Volts)
(Amps)
(Watts)
SHORT CIRCUIT TEST:
FORMULAE: Core loss: Wo = VoIo cos φ
o
Wo cos φ
o
Wo φ
= -------
o
= cos-1
Vo Io
------Vo Io
Iω = Io cos φ o (Amps)
Iµ = Io sin φ o (Amps)
V0 Ro = ------- Ω Iω
V0 Xo = ------- Ω Iµ
Vsc Zo2 = ------- Ω Isc
Xo2 = ( Zo2 - Ro22)1/2
R02 Ro1 = ------- Ω K2
X02 Xo1 = ------- Ω K2
Percentage Efficiency:
Wsc Ro2 = ------- Ω Isc2
V2 K= ------- = 2 V1
for all loads and p.f.
Output Power
(X) x KVA rating x 1000 x cos φ
Efficiency η % = -------------------- = -----------------------------------------------Input Power
Output power + losses
(X) x KVA rating x 1000 x cos φ = ------------------------------------------------------------(X) x KVA rating x 1000 x cos φ + Wo + X2Wsc Percentage Regulation: (X) x Isc (Ro2 cos φ ± Xo2sin φ ) x 100 + = lagging - = leading R% = -------------------------------------V2 Where X is the load and it is 1 for full load, ½ for half load, ¾ load, ¼ load etc.. and the power factor is, upf, o.8 p.f lag and 0.8 p.f lead
ISC o EQUIVALENT CIRCUIT: R
R
I
o1
o
o o
X
o1
L O A D
V
R
X
o
ZL′ = ZL/K2 N
Efficiency η %
MODEL GRAPHS:
% lagging
Output power (Watts)
Power factor
% leading
G +f220V I27A E -D +220V V (0-300)V (Amps) Vs Vs (Volts) V Fuse IfLOAD A V ,+ -II,ILLE DC o(0-20)A L L P (Amps) (Ext (Int Supply (Volts) MC Char) Char) 5 KW, A S 1 230V T RESULT: A2 Thus the efficiency and regulation of a transformer is predetermined by conducting open circuit test and short circuit test and the
equivalent circuit is drawn.
DEPARTMENT OF EEE LAB MANUAL CLASS SEMESTER SUBJECT CODE SUBJECT
: II YEAR MECH : III SEM : : Electrical Engineering Lab
S No 1
Name of the Experiment
2 3
Speed control of DC shunt motor (Armature, Field control)
4
Load test on single phase transformer
5
O.C & S.C Test on a single phase transformer
6
Regulation of an alternator by EMF & MMF methods.
7
V curves and inverted V curves of synchronous Motor
9 10 11
Date of
Experiment
submission
Load test on DC Shunt & DC Series motor O.C.C & Load characteristics of Separately excited and Self excited DC generator
8
Date of
Load test on three phase squirrel cage Induction motor Speed control of three phase slip ring Induction Motor Load test on single phase Induction Motor. Study of DC & AC Starters
Ex.No.1 a) LOAD TEST ON DC SHUNT MOTOR
Marks
Sign
AIM: To conduct load test on DC shunt motor and to find efficiency. APPARATUS REQUIRED: S.No. 1 2 3 4 5
Apparatus Ammeter Voltmeter Rheostat Tachometer Connecting Wires
Range (0-20)A (0-300)V 1250Ω , 0.8A (0-1500) rpm 2.5sq.mm.
Type MC MC Wire Wound Digital Copper
Quantity 1 1 1 1 Few
PRECAUTIONS: 1. DC shunt motor should be started and stopped under no load condition. 2. Field rheostat should be kept in the minimum position. 3. Brake drum should be cooled with water when it is under load.
PROCEDURE: 1. Connections are made as per the circuit diagram. 2. After checking the no load condition, and minimum field rheostat position, DPST switch is closed and starter resistance is gradually removed.
3. The motor is brought to its rated speed by adjusting the field rheostat. 4. Ammeter, Voltmeter readings, speed and spring balance readings are noted under no load condition. 5. The load is then added to the motor gradually and for each load, voltmeter, ammeter, spring balance readings and speed of the motor are noted. 6. The motor is then brought to no load condition and field rheostat to minimum position, then DPST switch is opened.
TABULAR COLUMN:
S.No.
Voltage V (Volts)
Current I (Amps)
Spring Balance Reading S1(Kg)
S2(Kg)
Circumference of the Brake drum
(S1∼ S2)Kg
=
Speed N (rpm)
Torque T (Nm)
cm.
Output Power Pm (Watts)
Input Power Pi (Watts)
Efficiency η %
FORMULAE: Circumference R
=
------------------- m 100 x2π
Torque T = (S1 ∼ S2) x R x 9.81 Nm
Input Power Pi = VI Watts 2π NT Output Power Pm = ------------ Watts 60 Output Power Efficiency η %
= -------------------- x 100% Input Power
Speed N (rpm)
y2
Speed N (rpm)
y3
Torque T (Nm)
Efficiency %
MODEL GRAPHS:
y1
N
y
η
T x Torque T (Nm)
Output Power (Watts)
RESULT: Thus load test on DC shunt motor is conducted and its efficiency is determined.
Ex.No.1 b) LOAD TEST ON DC SERIES MOTOR AIM: To conduct load test on DC Series Motor and to find efficiency. APPARATUS REQUIRED: S.No. 1 2
Apparatus Ammeter Voltmeter
3
Tachometer
4
Connecting Wires
Range (0-20)A (0-300)V (0-3000) rpm 2.5sq.mm.
PRECAUTIONS: 1. The motor should be started and stopped with load 2. Brake drum should be cooled with water when it is under load.
Type MC MC
Quantity 1 1
Digital
1
Copper
Few
PROCEDURE: 1. Connections are made as per the circuit diagram. 2. After checking the load condition, DPST switch is closed and starter resistance is gradually removed. 3. For various loads, Voltmeter, Ammeter readings, speed and spring balance readings are noted. 4. After bringing the load to initial position, DPST switch is opened.
TABULAR COLUMN:
S.No.
Voltage V (Volts)
Current I (Amps)
Spring Balance Reading S1(Kg)
S2(Kg)
(S1∼ S2)Kg
Speed N (rpm)
Torque T (Nm)
Output Power Pm (Watts)
Input Power Pi (Watts)
Efficiency η %
FORMULAE: Circumference R
=
------------------- m 100 x2π
Torque T = (S1 ∼ S2) x R x 9.81 Nm Input Power Pi = VI Watts 2π NT Output Power Pm = ------------ Watts 60 Output Power Efficiency η %
= -------------------- x 100% Input Power
y2
Speed N (rpm)
y3
Torque T (Nm)
Efficiency %
MODEL GRAPH:
y1 T E
N RESULT: Thus load test on DC series motor is conducted and its efficiency is determined. Output Power (Watts)
Ex.No.2 a) OPEN CIRCUIT CHARACTERISTICS OF SEPARATELY EXCITED DC SHUNT GENERATOR AIM: To obtain open circuit characteristics of separately excited DC shunt generator. APPARATUS REQUIRED: S.No. 1 2 3 4 5
Apparatus Ammeter Voltmeter Rheostats Tachometer Connecting Wires
Range (0-1)A (0-300)V 1250Ω , 0.8A (0-1500)rpm 2.5sq.mm.
Type MC MC Wire Wound Digital Copper
Quantity 1 1 2 1 Few
PRECAUTIONS: 1. The field rheostat of motor should be in minimum resistance position at the time of starting and stopping the machine. 2. The field rheostat of generator should be in maximum resistance position at the time of starting and stopping the machine.
PROCEDURE: 1. Connections are made as per the circuit diagram. 2. After checking minimum position of motor field rheostat, maximum position of generator field rheostat, DPST switch is closed and starting resistance is gradually removed. 3. By adjusting the field rheostat, the motor is brought to rated speed. 4. By varying the generator field rheostat, voltmeter and ammeter readings are taken. 5. After bringing the generator rheostat to maximum position, field rheostat of motor to minimum position, DPST switch is opened.
TABULAR COLUMN: S.No.
Eo (Volts)
MODEL GRAPH:
If (Amps)
Field Current
Armature Voltage
If (Amps)
Eo (Volts)
RESULT: Thus open circuit characteristics of separately excited DC shunt generator is obtained.
Ex.No.2 b) LOAD CHARACTERISTICS OF SEPARATELY EXCITED DC SHUNT GENERATOR AIM: To obtain internal and external characteristics of DC separately excited DC shunt generator. APPARATUS REQUIRED: S.No.
Apparatus
1
Ammeter
2 3 4 5 6
Voltmeter Rheostats Loading Rheostat Tachometer Connecting Wires
Range (0-2)A
Type MC
Quantity 1
(0-20) A (0-300)V 1200Ω , 0.8A 5KW, 230V (0-1500)rpm 2.5sq.mm.
MC MC Wire Wound Digital Copper
1 1 2 1 1 Few
PRECAUTIONS: 1. The field rheostat of motor should be at minimum position. 2. The field rheostat of generator should be at maximum position. 3. No load should be connected to generator at the time of starting and stopping. PROCEDURE: 1. Connections are made as per the circuit diagram.
2. After checking minimum position of DC shunt motor field rheostat and maximum position of DC shunt generator field rheostat, DPST switch is closed and starting resistance is gradually removed. 3. Under no load condition, Ammeter and Voltmeter readings are noted, after bringing the voltage to rated voltage by adjusting the field rheostat of generator. 4. Load is varied gradually and for each load, voltmeter and ammeter readings are noted. 5. Then the generator is unloaded and the field rheostat of DC shunt generator is brought to maximum position and the field rheostat of DC shunt motor to minimum position, DPST switch is opened.
DETERMINATION OF ARMATURE RESISTANCE:
Fuse
+
27A
220V DC Supply
D P S T S W I T C H
-
+
A
-
(0-20)A MC A1
+ V
G
LOAD 5 KW, 230V 27A Fuse
PROCEDURE: 1. Connections are made as per the circuit diagram. 2. Supply is given by closing the DPST switch. 3. Readings of Ammeter and Voltmeter are noted. 4. Armature resistance in Ohms is calculated as Ra = (Vx1.5) /I
TABULAR COLUMN:
A2
(0-300)V MC
S.No.
Voltage
Current
Armature Resistance
V (Volts)
I (Amps)
Ra (Ohms)
TABULAR COLUMN:
S.No.
Field
Load
Terminal
Current
Current
Voltage
If (Amps)
IL (Amps)
(V) Volts
FORMULAE: Eg
=
V + Ia Ra (Volts)
Ia
=
IL + If (Amps)
Ia = IL + If (Amps)
Eg =V + Ia Ra (Volts)
Eg
:
Generated emf in Volts
V
:
Terminal Voltage in Volts
Ia
:
Armature Current in Amps
IL
:
Line Current in Amps
If
:
Field Current in Amps
Ra
:
Armature Resistance in Ohms
VL, E (Volts)
MODEL GRAPH:
E Vs IL (Int Char) V Vs IL (Ext Char) RESULT: Thus load characteristics of separately excited DC shunt generator is obtained.
Ex.No.2 c)
If, IL (Amps)
OPEN CIRCUIT CHARACTERISTICS OF SELF EXCITED
DC SHUNT GENERATOR AIM: To obtain open circuit characteristics of self excited DC shunt generator and to find its critical resistance. APPARATUS REQUIRED: S.No. 1 2 3 4 5 6
Apparatus Ammeter Voltmeter Rheostats SPST Switch Tachometer Connecting Wires
Range (0-1)A (0-300)V 1250Ω , 0.8A (0-1500)rpm 2.5sq.mm.
Type MC MC Wire Wound Digital Copper
Quantity 1 1 2 1 1 Few
PRECAUTIONS: 1. The field rheostat of motor should be in minimum resistance position at the time of starting and stopping the machine. 2. The field rheostat of generator should be in maximum resistance position at the time of starting and stopping the machine. 3. SPST switch is kept open during starting and stopping.
PROCEDURE: 1. Connections are made as per the circuit diagram. 2. After checking minimum position of motor field rheostat, maximum position of generator field rheostat, DPST switch is closed and starting resistance is gradually removed.
3. By adjusting the field rheostat, the motor is brought to rated speed. 4. Voltmeter and ammeter readings are taken when the SPST switch is kept open. 5. After closing the SPST switch, by varying the generator field rheostat, voltmeter and ammeter readings are taken. 6. After bringing the generator rheostat to maximum position, field rheostat of motor to minimum position, SPST switch is opened and DPST switch is opened.
TABULAR COLUMN: S.N o.
Field
Armature
Current
Voltage
If (Amps)
Eo (Volts)
Eo (Volts)
MODEL GRAPH:
Critical Resistance = Eo / If Ohms
If RESULT:
Eo
Thus open circuit characteristics of self excited DC shunt generator are obtained and its critical resistance is determined. If (Amps)
Ex.No.2 d) LOAD CHARACTERISTICS OF SELF EXCITED DC SHUNT GENERATOR AIM: To obtain internal and external characteristics of DC shunt generator. APPARATUS REQUIRED: S.No.
Apparatus
1
Ammeter
2 3 4 5 6
Voltmeter Rheostats Loading Rheostat Tachometer Connecting Wires
Range (0-2)A
Type MC
Quantity 1
(0-20) A (0-300)V 1200Ω , 0.8A 5KW, 230V (0-1500)rpm 2.5sq.mm.
MC MC Wire Wound Digital Copper
1 1 2 1 1 Few
PRECAUTIONS: 1. The field rheostat of motor should be at minimum position. 2. The field rheostat of generator should be at maximum position. 3. No load should be connected to generator at the time of starting and stopping. PROCEDURE: 1. Connections are made as per the circuit diagram.
2. After checking minimum position of DC shunt motor field rheostat and maximum position of DC shunt generator field rheostat, DPST switch is closed and starting resistance is gradually removed. 3. Under no load condition, Ammeter and Voltmeter readings are noted, after bringing the voltage to rated voltage by adjusting the field rheostat of generator. 4. Load is varied gradually and for each load, voltmeter and ammeter readings are noted. 5. Then the generator is unloaded and the field rheostat of DC shunt generator is brought to maximum position and the field rheostat of DC shunt motor to minimum position, DPST switch is opened.
DETERMINATION OF ARMATURE RESISTANCE:
Fuse
+
27A
220V DC Supply
D P S T S W I T C H
-
+
A
-
(0-20)A MC A1
+ V
G
LOAD 5 KW, 230V 27A Fuse
PROCEDURE: 1. Connections are made as per the circuit diagram. 2. Supply is given by closing the DPST switch. 3. Readings of Ammeter and Voltmeter are noted. 4. Armature resistance in Ohms is calculated as Ra = (Vx1.5) /I
A2
(0-300)V MC
TABULAR COLUMN: S.No.
Voltage
Current
Armature Resistance
V (Volts)
I (Amps)
Ra (Ohms)
TABULAR COLUMN:
S.No.
Field
Load
Terminal
Current
Current
Voltage
If (Amps)
IL (Amps)
(V) Volts
FORMULAE:
Ia = IL + If (Amps)
Eg =V + Ia Ra (Volts)
Eg
=
V + Ia Ra (Volts)
Ia
=
IL + If (Amps)
Eg
:
Generated emf in Volts
V
:
Terminal Voltage in Volts
Ia
:
Armature Current in Amps
IL
:
Line Current in Amps
If
:
Field Current in Amps
Ra
:
Armature Resistance in Ohms
VL, E (Volts)
MODEL GRAPH:
E Vs IL (Int Char) V Vs IL (Ext Char) RESULT: Thus the load characteristicsIof excited DC shunt generator is obtained. , I self (Amps) f
L
Ex.No. 3 SPEED CONTROL OF DC SHUNT MOTOR AIM: To obtain speed control of DC shunt motor by a. Varying armature voltage with field current constant. b. Varying field current with armature voltage constant APPARATUS REQUIRED: S.No. 1 2
Apparatus Ammeter Voltmeter
3
Rheostats
4 5
Tachometer Connecting Wires
Range (0-20) A (0-300) V 1250Ω , 0.8A
Type MC MC Wire
50Ω , 3.5A (0-3000) rpm 2.5sq.mm.
Wound Digital Copper
Quantity 1 1 Each 1 1 Few
PRECAUTIONS: 1. Field Rheostat should be kept in the minimum resistance position at the time of starting and stopping the motor. 2. Armature Rheostat should be kept in the maximum resistance position at the time of starting and stopping the motor.
PROCEDURE: 1. Connections are made as per the circuit diagram. 2. After checking the maximum position of armature rheostat and minimum position of field rheostat, DPST switch is closed
(i) Armature Control: 1. Field current is fixed to various values and for each fixed value, by varying the armature rheostat, speed is noted for various voltages across the armature. (ii) Field Control: 1. Armature voltage is fixed to various values and for each fixed value, by adjusting the field rheostat, speed is noted for various field currents. 2. Bringing field rheostat to minimum position and armature rheostat to maximum position DPST switch is opened.
TABULAR COLUMN: (i) Armature Voltage Control:
S.No.
If1 = Armature Voltage
Speed
If2 = Armature
N (rpm)
Voltage
Va ( Volts)
Speed
If3 = Armature
Speed
N (rpm)
Voltage
N (rpm)
Va ( Volts)
Va ( Volts)
Va2 = Field
Va3 = Field
(ii) Field Control: Va1 = Field S.No.
Speed
Current
N (rpm)
If (A)
If1
MODEL GRAPHS:
N (rpm)
Current If (A)
Speed N (rpm)
Speed N (rpm)
If (A)
Current
Speed
If2 If3
Va1 Va3 Va2
Va (Volts)
If (Amps)
Speed N (rpm)
RESULT: Thus the speed control of DC Shunt Motor is obtained using Armature and Field control methods.
Ex.No. 4
LOAD TEST ON A SINGLE PHASE TRANSFORMER AIM: To conduct load test on single phase transformer and to find efficiency and percentage regulation. APPARATUS REQUIRED: S.No.
Apparatus
1
Ammeter
2
Voltmeter
3
Wattmeter
4
Auto Transformer
5
Resistive Load
6
Connecting Wires
Range (0-10)A
Type MI
Quantity 1
(0-5) A (0-150)V
MI MI
1 1
(0-300) V (300V, 5A)
MI Upf
1 1
(150V, 5A) 1φ , (0-
Upf
1
-
1
-
1
Copper
Few
260)V 5KW, 230V 2.5sq.mm
PRECAUTIONS: 1. Auto Transformer should be in minimum position. 2. The AC supply is given and removed from the transformer under no load condition. PROCEDURE: 1. Connections are made as per the circuit diagram.
2. After checking the no load condition, minimum position of auto transformer and DPST switch is closed. 3. Ammeter, Voltmeter and Wattmeter readings on both primary side and secondary side are noted. 4. The load is increased and for each load, Voltmeter, Ammeter and Wattmeter readings on both primary and secondary sides are noted. 5. Again no load condition is obtained and DPST switch is opened.
TABULAR COLUMN:
S.No.
Load
V1 (Volts)
Primary I1 (Amps)
W1 (Watts)
Secondary V2 I2 W2 (Volts) (Amps) (Watts)
Input Power W1 x MF
Output Power W2 x MF
Efficiency η %
% Regulation
FORMULAE: Output Power = W2 x Multiplication factor Input Power = W1 x Multiplication factor Output Power Efficiency η %
= -------------------- x 100% Input Power VNL - VFL (Secondary)
Regulation R % = ------------------------------ x 100% VNL
Regulation R %
Efficiency η %
MODEL GRAPHS:
η R
RESULT: Thus the load test on single phase transformer is conducted.
Output Power (Watts)
Ex.No. 13 OPEN CIRCUIT & SHORT CIRCUIT TEST ON A SINGLE PHASE TRANSFORMER AIM: To predetermine the efficiency and regulation of a transformer by conducting open circuit test and short circuit test and to draw equivalent circuit. APPARATUS REQUIRED: S.No.
Apparatus
1
Ammeter
2
Voltmeter
3
Wattmeter
4
Connecting Wires
Range (0-2)A
Type MI
Quantity 1
(0-5) A (0-150)V (150V, 5A)
MI MI LPF
1 2 1
(150V, 5A) 2.5sq.mm
UPF Copper
1 Few
PRECAUTIONS: 1. Auto Transformer should be in minimum voltage position at the time of closing & opening DPST Switch.
PROCEDURE: OPEN CIRCUIT TEST:
1. Connections are made as per the circuit diagram. 2. After checking the minimum position of Autotransformer, DPST switch is closed. 3. Auto transformer variac is adjusted get the rated primary voltage. 4. Voltmeter, Ammeter and Wattmeter readings on primary side are noted. 5. Auto transformer is again brought to minimum position and DPST switch is opened. SHORT CIRCUIT TEST: 1. Connections are made as per the circuit diagram. 2. After checking the minimum position of Autotransformer, DPST switch is closed. 3. Auto transformer variac is adjusted get the rated primary current. 4. Voltmeter, Ammeter and Wattmeter readings on primary side are noted. 5. Auto transformer is again brought to minimum position and DPST switch is opened.
TABULAR COLUMN: OPEN CIRCUIT TEST: Vo
Io
Wo
(Volts)
(Amps)
(Watts)
Vsc
Isc
Wsc
(Volts)
(Amps)
(Watts)
SHORT CIRCUIT TEST:
FORMULAE: Core loss: Wo = VoIo cos φ
o
Wo cos φ
o
Wo φ
= -------
o
= cos-1
Vo Io
------Vo Io
Iω = Io cos φ o (Amps)
Iµ = Io sin φ o (Amps)
V0 Ro = ------- Ω Iω
V0 Xo = ------- Ω Iµ
Vsc Zo2 = ------- Ω Isc
Xo2 = ( Zo2 - Ro22)1/2
R02 Ro1 = ------- Ω K2
X02 Xo1 = ------- Ω K2
Percentage Efficiency:
Wsc Ro2 = ------- Ω Isc2
V2 K= ------- = 2 V1
for all loads and p.f.
Output Power
(X) x KVA rating x 1000 x cos φ
Efficiency η % = -------------------- = -----------------------------------------------Input Power
Output power + losses
(X) x KVA rating x 1000 x cos φ = ------------------------------------------------------------(X) x KVA rating x 1000 x cos φ + Wo + X2Wsc Percentage Regulation: (X) x Isc (Ro2 cos φ ± Xo2sin φ ) x 100 + = lagging - = leading R% = -------------------------------------V2 Where X is the load and it is 1 for full load, ½ for half load, ¾ load, ¼ load etc.. and the power factor is, upf, o.8 p.f lag and 0.8 p.f lead
ISC o EQUIVALENT CIRCUIT: R
R
I
o1
o
o o
X
o1
L O A D
V
R
X
o
ZL′ = ZL/K2 N
Efficiency η %
MODEL GRAPHS:
% lagging
Output power (Watts)
Power factor
% leading
G +f220V I27A E -D +220V V (0-300)V (Amps) Vs Vs (Volts) V Fuse IfLOAD A V ,+ -II,ILLE DC o(0-20)A L L P (Amps) (Ext (Int Supply (Volts) MC Char) Char) 5 KW, A S 1 230V T RESULT: A2 Thus the efficiency and regulation of a transformer is predetermined by conducting open circuit test and short circuit test and the
equivalent circuit is drawn.
Related Documents 171j1w
Electrical Engineering Lab Manual For Ii Mech Part I 3p5c6g
November 2021 0
Basic Electrical Engineering Lab Manual 4c564o
December 2019 44
Engineering Practice Lab Manual(electrical And Electronics) 6c1c24
October 2019 106
Electrical Skills Lab Manual 6l652s
November 2019 109
3yr 1sem Mech Thermal Engineering Lab Manual (63) 4db4o
November 2021 0
Electrical Circuit Lab Manual 126p3e
November 2019 67More Documents from "Arivumani" 6w6b29
17pepe09 Distributed Generation And Microgrid Syllabus 1y21y
November 2021 0
Electrical Engineering Lab Manual For Ii Mech Part I 3p5c6g
November 2021 0
New First Year Electrical Lab Manual 312a71
December 2019 40
Trb Polytechnic - Trb Material For Preparation In Lecturers Recruitment In Government Polytechnic Colleges 535j2m
November 2019 618