This is a speed motor controller circuit of a 12V DC motor. as SCR DC motor speed control circuit using IC-CMOS. You can adjust the speed of rotation of the spindle motor from 5 to 60 cycles per minute.
How does it work
To begin with, the 12V AC voltage from the Secondary transformer comes to bridge diode-BD1. It rectifies from AC (Alternating Current) to DC (pulsed DC).
SCR DC motor speed control circuit using IC-CMOS
This can use for DC motor and SCR1—The SCR needs to use DC to A-K lead—. Which uses just the pulsed DC only.
But we also use digital IC.
Cr: Photo Power SCR Bridgold
Second, we use one NAND gate CMOS-IC, CD4081. It requests a stable power supply to pin 14. The D2 gets the pulsed DC to filter to smooth DC current with C2-220uF.
Pin 1 gets the pulsed DC directly. And the other into pin 2. Next, The VR1, C1, and R1 are the phase shift circuit to delay the pulse DC to slow down.
After that, the pulsed DC from pin 3 to triggers the gate of SCR1 to turn on.
The working of SCR like switches on-off the pulsed DC to the motor, makes it rotate. The Speed of the motor can adjust by VR1.
If pulsed DC has a “high” state more than a “low” state. It makes more current to the DC motor, it rotates very fast.
But in the opposite way, the “high” is less than the “low” state. It rotates too slowly.
The D1 prevents the noise from the motor.
The D3 is reverse-voltage protection of motors. This can cause circuit damage.
If the circuit uses the high power motor. You need to install a large heat sink to BD1, D1, and SCR1. Because they are very hot, may damage.
How to builds
This project is easy because uses a few parts. For faster building, if we assemble these circuits in the Universal PCB Figure 2 is the components layout for a guide.
Figure 2 the components layout of the DC motor controller diagram with SCR and CMOS IC.
Learn more: SCR circuit diagram
The components lists.
IC1: CD4081, CMOS Nand gate IC
SCR1: SCR-C106D or equivalent
BD1: Bridge Diode 6A 200V
D1: 1N5401, 3A 100V diode
D2, D3: 1N4004, 1A 400V Diode.
T1: Transformer 3A 12V
C1: 1uF 16V Electrolytic capacitors
C2: 220uF 16V Electrolytic capacitors
VR1: 5K potentiometer
R1: 5.6K, 0.25W resistors
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