Download lab 2

Electrical Machines I
Laboratory Assignment 2
SHUNT REGULATOR MV1905
REGULADOR SHUNT
440 OHM
0
DIRECT CURRENT MACHINE
GENERATOR: 2.1 kW 230V
MOTOR: 2.0kW 230V
F1
F2
A1
A2
220
220
220V~
MAX 2.0A
0
-
+
-
+
-
0
1
1
1
220V-
1
0-220V -
30V
S
T
D
R
S
T
1
1
1
1
0
0
3*0-220V
220V/127V ~
I
1A
150V
V
D
0
0
0
0
U
R
+
0
300V
2A
VOLTMETER
AMPEREMETER
AMPERIMETRO
A
Using the above devices, copy, label and connect the motor terminals using the diagrams
shown so that the motor is connected as a separately excited dc motor found in lab. You
may use more measuring devices than the ones in figure. Please indicate clearly the
following:
 Field winding connection
o Field voltage measurement
o Field current measurement
 Armature winding connection
o Armature current measurement
o Armature voltage measurement
i.e. for the selected measuring devices, please indicate which scale have you used to run
the 2.1 kW motor.
Test your knowledge:
1. Why does the armature ammeter reads a slight deflection of current when the motor
is at no-load?
……………………………………………………………………………………………
……………………………………………………………………………………………
……………………………………………………………………………………………
…………………………………………………………………………………………….
2. What do you think the speed of the motor be (increase or decrease) when a load is
applied on the motor shaft?
……………………………………………………………………………………………
……………………………………………………………………………………………
……………………………………………………………………………………………
…………………………………………………………………………………………….
3. Why is the motor field set to maximum when it is running as a motor? Will it be set
maximum when the machine is run as generator?
……………………………………………………………………………………………
……………………………………………………………………………………………
……………………………………………………………………………………………
…………………………………………………………………………………………….
4. Why does a dc motor run faster when the field current is reduced?
……………………………………………………………………………………………
……………………………………………………………………………………………
……………………………………………………………………………………………
…………………………………………………………………………………………….
5. What will happen to the armature and field currents when the motor is loaded?
…………………………………………………………………………………………
…………………………………………………………………………………………
…………………………………………………………………………………………
…………………………………………………………………………………………
6. What is needed to connect this machine as a generator?
…………………………………………………………………………………………
…………………………………………………………………………………………
…………………………………………………………………………………………
………………………………………………………………………………………..