Over-Volting

Over-volting a DC motor is a great way to get more power, if the motor can handle it. Can the 12 volt HTI motors handle 24 volts? It depends on your design. Here are some questions that you may be asking and some answers that will help you.

What's the big advantage of running a DC motor at double the voltage?

Quadruple the power!

What are the big disadvantage of doubling the voltage?

Quadruple the heat!

How much is too much heat?

It depends on how much current your motors will be drawing. The more current they draw, the more heat they produce. Larger wheels, more traction, heavier robots, pushing, and four wheel designs all increase current draw. When the motors produce heat faster than they can dissipate it, their temperature goes up. When the temperature gets too high, the motor smokes and is ruined.

So how can I figure out if I can run them at 24 volts?

The only way to know for sure is to try it. Here's a safe way of doing it.

Wire your SS2's for 24 volts. Set your PWM outputs to their maximum range and calibrate your IFI speed controllers. Now reduce the range of your PWM outputs to about 50%. Drive your robot around as you would in competition and immediately check the temperature of the drive motors. If they feel cool, or slightly warm, you can wait for the motors to cool then increase the PWM range and repeat the test. Keep increasing the PWM throws and checking the motors until the motors seem hot or until you've increased the throws to 100%.

Break-in

For best results, PMDC motors should be broken-in. This allows the brushes to form concave surfaces around the commutator, maximizing contact area. It also helps remove any sharp edges on the commutator that may have been left during the manufacturing process.

We recommend breaking in motors using water. Connect wires to the motor and place the motor in a jar of water. Run the motor at 3 volts (or just enough to get it spinning slowly). Stop running the motor after 15 minutes or when the water turns black. Pull the motor out of the water, dry the motor (with shop air or "buggy blast"), and lubricate the bearings with a drop of oil.

Your motor is now ready to run at its maximum potential. Break-in must be done before the motor is run at full voltage This is especially useful if the motor will be over-volted.