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Power Electronic Drives (EET421)
Laboratory Module
EXPERIMENT 2
Single-Phase Half-Wave Rectifier with DC Motor Load
Objective :
To study the concept of a DC motor controlled by adjusting the AC voltage supply, using
a power diode for half-wave rectification, its harmonics and power factor characteristics.
Introduction :
A DC motor normally contributes to spikes, voltage disturbances, harmonics , low PF to
the main power system and lower the power supply quality.
In this particular experiment, an AC supply source with difference voltage selection is
used to supply DC voltage to a DC motor through a power diode (as an AC to DC power
converter).
The motor with a power diode should have different performance and characteristics.
The speed, harmonics, total harmonic distortion (THD) and power factor should be
observed as these will have significant impact of affecting the motor and power system.
Equipment and Parts :
1) ED machine trainer No-5306 AC/DC Power Supply
2) ED machine trainer No-5310 AC/DC m/c field frame
3) ED Yoke-A09, field winding-A03 , brush-A17 and permanent magnets.
4) 5A Power Diode -1pc
5) Power Analyzer
6) Wires
Procedure :
1) Connect the circuit as given below in Fig 1.0. Remember to build the permanent
magnet DC motor using items (3) on the frame of the electrical machine trainer.
2) In the first part of this experiment, connect the power diode as the power converter
device to a 100 Ohm resistor. After ensure your connection is correct, turn-on the
power of the AC supply.
3) On ED-5306, there are 0Vac, 6Vac, 12Vac, 24Vac and 50Vac supply terminals.
Please note that DON’T CHOOSE the 50Vac supply terminal because the DC motor
will be damaged due to higher voltage and current ratings.
4) Referring to the Table 1.0, record the readings accordingly. You will need the AC
supply voltage (Vrms) of 6Vac, 12Vac, 18Vac and 24Vac for the data. The 18Vac
supply is made by connecting between 6Vac and 24Vac terminals.
UNIVERSITI MALAYSIA PERLIS – Exp.2
1
Power Electronic Drives (EET421)
Table 1.0
Vrms
Laboratory Module
For load resistor =100 Ohms.
Irms
Load
100
100
100
100
100
THDv
THDi
W
PF
After completed Table 1.0, replace the 100 Ohm resistor with the DC motor and
record the data as in Table 1.1.
Table 1.1
Vrms
Irms
Speed
THDv
THDi
W
PF
5) After you have completed the table, plot graphs of speed against voltage, speed
against current, current THD (THDi) against speed and voltage against power.
6) Explain the behaviours of each graph that you have plotted.
7) What make you think that current THD (THDi) is much higher than voltage THD
(THDv) ?
8) Compare the speed and power of this experiment with your previous lab ( Experiment
1) data. Which type of converters that delivering more power to the motor? Please
explain your reason.
9) Please state your overall conclusion for the whole of this experiment.
UNIVERSITI MALAYSIA PERLIS – Exp.2
2