varying speed electric moter?

Question

ok, so a basic electric motor is a ball of copper wire that turns when electricity is applied... I want to take that motor and make it so I can vary the speed of it, like the harder you press the botton, the faster it will go.

what do I need????

Answer 1

If you have a DC motor, then you're good to go. Just vary the input voltage.

If you have an AC motor, then you're going to have to vary the 60 Hz. frequency. This is rather complicated and, since you've posed the question the way you did, is most likely beyond the scope of what you can handle.

Answer 2

If it is a DC motor, then the truly electronic way of doing it would be to use a regulator such as the LM317. There is a variation of this regulator that will handle up to 5 amps. Just be sure to use a good heat sink to dissipate heat that will be generated. You'll still use a potentiometer in the circuit for the regulator, but it could be a half watt device as opposed to the giant one you would need for any appreciable current load just using a potentiometer by it's self.
If you are talking about an AC motor, then you need a SCR, or better yet, a TRIAC based controller. Rather than the awkward and expensive control of the 60Hz frequency, for the sake of simplicity, the TRIAC turns on, and off the flow of the applied voltage to the motor. The TRIAC type device is going to use both sides of the applied voltage wave to control the motor speed. Basically, you need a fan speed controller for up to 1 HP and companies like Grainger Industrial Supply have them for about $30 or less.
While there are speed controllers that do vary the frequency of the applied voltage to control motor speed, they are expensive, and out of your league for what you want to do.

Answer 3

If you are going to make the motor your self and the controller you should look for a DC motor. Then you can vary the voltage to change the speed. Hookup up a AA battery then 9V you will see the difference. You can get fancy and do pulse width modulation (PWM) if you like. Search the internet you make one with some nails and wire. You can also vary the speed by using a potentiometer in series with the motor but this has to be properly sized or it will burn up.

To make an AC motor and control the speed is a totally different ball game. You have to vary the frequency of the AC power to change the speed of the motor. If you going to buy something look for variable frequency drive or VFD.

Good luck with your ball of copper...

Answer 4

If it is a small, low-voltage DC motor, you could make a variable resistor from carbon grains or powdered graphite. If you put the carbon under the button, the harder you press, the more electricity goes through the carbon grains. Old telephone microphones used that mechanism.
Don't try this with more than ~12 volts DC (shock danger), and no more than a few hundred milliamperes (a very small motor) or the carbon could get hot enough to burn you or start a fire.

Answer 5

That depends on the type of motor. The easiest one to control is a series-wound DC motor, since its speed will vary with applied voltage. A variable-voltage DC power supply will do the job, but you have to figure out how to mechanically couple the button to the power supply voltage control.

Answer 6

Assuming that you are powering your motor using direct current (DC), and not alternating current (AC), you can get yourself a potentiometer (otherwise known as a variable resistor).
Place the potentiometer in line with the power to the motor, and voila, you should be able to vary the speed of your motor!

You can get potentiometers from electronics stores, such as Dick Smith Electronics (in Australia) or Jaycar (in Australia). They come in different styles, and different resistance values.

You can use Ohm's Law ( E = I . R , or Voltage = Current x Resistance) to determine what resistance value your potentiometer requires

Answer 7

Think about a model train. The engine is the motor and the transformer controls the amount of current to the train.

You would need a transformer to control the amount of current going to the motor. Use a DC motor and transformer to be safe.

Answer 8

I used an inverter. It varies the amount of power that is delivered to the motor. The one that I used had a rotary control and could vary he speed of a motor from zero rpm up to the top rated speed. Beware though, if you run a 500 rpm motor at low speeds, it will overheat. You could run the motor though a variable speed gearbox so that it always ran at optimum speed but the output at the gearbox is infinitely variable.

Answer 9

You will a Variable Resistor