SOLAR PV CONTROL SYSTEM.pdf

3. Simple circuitry is desired. A very basic drive for controlling speed and
torque would require a little more than a large enough potentiometer.
4. D.C motors provide continuous current and would be appropriate for
application like driving wheels.
From the start, DC motors are quite simple, apply a voltage to both terminals, and it
spins. If you want to control which direction the motor spins just reverse the wires.
Email: david.irungu@stu.kuct.ac.ke
Figure 2: A DC Motor
If you want the motor to spin at half that speed; then use less voltage. Some
considerations when using D.C motors are:
• Voltage: DC motors are non-polarized - meaning that one can reverse voltage
without any damage. Typical DC motors are rated from about 6V-12V. The larger
ones are often 24V or more. But for the purposes of a robot, you probably will stay
in the 6V-12V range. Voltage is directly related to motor speed as current is related
to motor torque i.e. the more the voltage, the higher the torque. A DC motor is rated
at the voltage it is most efficient at running. If you apply too few volts, it just won’t
work. If you apply too much, it will overheat and the coils will melt. So the general
rule is, try to apply as close to the rated voltage of the motor as you can. Also,
although a 24V motor might be stronger, consider that it will need a 24v battery
which increases the initial load. Unless really high torque needs to be overcome it’s
better to stick to the 6-12V motors.
• Current: As with all circuitry, attention must be paid to current. Too little won’t
work and too much, meltdown occurs. When buying a motor, there are two current
ratings you should pay attention to. The first is operating current. This is the
16
2012