How to build a controller for an electric DC motor
DC electric motors come in a wide variety of sizes and shapes from the tiny driver in an HO scale electric train to fifty ton locomotives. Controlling a DC electric motor requires being able to vary the input voltage to the motor’s coil while maintaining an amperage level high enough to keep the coil spinning. Building a controller for your particular DC electric motor should take into consideration the levels of voltage, amperage and load factors necessary to do your intended job.
Things You'll Need
- Selected resistors, capacitors, diodes and Integrated Circuits (ICs)
- Circuit board
- Soldering iron
- Electrical tool kit (wire cutter/stripper, needle nose pliers, alligator clips, assorted connectors)
- potentiometer or variable resistor (resistance dependent on DC motor size)
- Wiring
- Controller container
Instructions
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1
Determine the DC voltage and amperage of the electric motor you are attempting to define the size and value of the circuit components required to carry the current necessary to control the motor.
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2
Determine the requirements of the DC electric motor’s function. Consider if it is required to spin in one direction only or does it require reverse direction and if the input gradient requires a wide or narrow range to perform the DC motor’s job.
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3
Draw a schematic diagram of the circuit you have decided upon. Keep it as simple as possible. Many examples are available on the Internet to use as a guide for your circuit.
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4
Assemble the resistors, capacitor(s), diodes and IC(s) on the circuit board, but do not solder the connections. Use insulated wired alligator clips to connect the components.
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5
Test the rig by setting the potentiometer, or variable resistor, at zero and connecting the positive and negative controller leads to the DC electric motor. Apply the current and slowly turn the potentiometer. If the motor responds to the increased current level, disconnect the power and the DC motor, and apply solder to the circuit board wires and mount the DC controller in the container.
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Tips & Warnings
Numerous DC electric motor controller kits are available to perform many specific jobs. They generally come with detailed instructions and are usually less expensive than purchasing the required components separately. If using a CMOS IC, always use an antistatic wrist band.
Working with electric current can be dangerous regardless of the level of amperage. Always recheck connections; one misstep can fry an IC in the blink of an eye. Avoid moisture when working with electric current.
References
Resources
- Photo Credit Dan Callister/Getty Images Entertainment/Getty Images
