Page 333 - Electronic Mechanic - TP - Volume - 2

ELECTRONICS MECHANIC - CITS

• Lowering the firing angle decreases the effective voltage applied to the motor, slowing it down, and vice
versa.
5 Advantages:
• SCR chopper control offers smooth speed control over a wide range.

• It allows for efficient energy usage by controlling the motor’s power consumption.
6 Applications:
• SCR chopper control is commonly used in applications where precise speed control of DC motors is
required, such as in traction systems, industrial drives, and electric vehicle

7 Setup Components:

• Connect the DC shunt motor to the output terminals of the SCR chopper module.
• Connect the power supply to the input terminals of the SCR chopper module.
• Connect the control circuit to the SCR chopper module. If using a potentiometer, connect it to the control
input of the chopper module. If using a microcontroller, ensure proper interfacing is done.

8 Power On:
• Turn on the power supply and set it to the desired voltage level.
• Ensure that all connections are secure and correct to avoid any short circuits or accidents.
9 Adjust Firing Angle:
• If using a potentiometer for manual control, adjust the potentiometer knob to vary the firing angle of the SCR.

• If using a microcontroller for automatic control, upload the control algorithm to the microcontroller and adjust
any parameters as necessary.
10 Observe Motor Speed:
• As you adjust the firing angle of the SCR, observe the speed of the DC motor.

• Increasing the firing angle will increase the average voltage applied to the motor, resulting in higher speed,
and vice versa.
11 Fine-tuning:

• Fine-tune the firing angle until you achieve the desired speed of the motor.
• Use a multimeter to measure the voltage and current to ensure they are within safe operating limits for the
motor.

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CITS : E & H - Electronics Mechanic - Exercise 222