is it possible to increase electrical input into an electrical engine?

[Elite Engineer]

I took apart an old air conditioner, and attached a belt to the rod on the fan, and intend to use it to drive a pulley, however the fan doesnt have enough strength to fully spin with the load attached (the fan puts out 0.03 hp). Is there a way to increase the volts going into the eletrical engine to give it more force to rotate with the load attached.

 

I has 120 volts flowing through, is it possible to have 140, 180, 240 volts?

 

~EE

[EdEarl]

You could use a variac; although, you might not find one that puts out that much voltage. Thus, a variac and a 1:2 transformer could do the job. Or, use a multi-output transformer, one with taps for 120, 130, 140, ... volts, for example. However, increasing the voltage on a motor will cause it to heat more, and reduce its life span. It is better, and probably cheaper to buy a more powerful motor.

Induction motors are usually the least expensive, and are often inefficient, which means you will use more money in electricity than the cost of buying a more expensive synchronous motor, unless your use is very intermittent.

[doG]

I took apart an old air conditioner, and attached a belt to the rod on the fan, and intend to use it to drive a pulley, however the fan doesnt have enough strength to fully spin with the load attached (the fan puts out 0.03 hp). Is there a way to increase the volts going into the eletrical engine to give it more force to rotate with the load attached.

 

I has 120 volts flowing through, is it possible to have 140, 180, 240 volts?

 

~EE

You could but the motor probably won't last long if you do. The wire size used in the windings is based on the current through the windings when the motor is used at the design voltage. Upping the voltage will increase the current since the resistance will remain the same. It is common for the manufacturers of such unit to go back and do cost engineering after the initial design engineering is complete to get the cost down to the bare minimum which means using a wire gauge that is minimally sufficient for the design voltage and horsepower.

 

BTW, you said you got this fan motor from an old air conditioner. Is the compressor motor good in that air conditioner? It will be rated for more horsepower than the fan motor. You might could use it instead.

[Elite Engineer]

 

 

BTW, you said you got this fan motor from an old air conditioner. Is the compressor motor good in that air conditioner? It will be rated for more horsepower than the fan motor. You might could use it instead.

Yes, the compressor is in excellent condition. How could I use it for more power?

[Delbert]

I think you will find a fan motor is designed to only drive a fan. I understand that more often than not a modern fan is a brushless motor - as distinct from an induction motor. Whereby electronics and Hall Effect sensors are used to switch the current through the coils. In contrast to older motors which used a commutator and carbon brushes.

 

I has 120 volts flowing through, is it possible to have 140, 180, 240 volts?

Small point. Volts don't flow through. Voltage is the applied potential to cause a current to flow through.

[doG]

Yes, the compressor is in excellent condition. How could I use it for more power?

The motor that drives the compressor will have more power than the fan motor.

[john5746]

Also consider gear ratio if you haven't done so already.

[Enthalpy]

Many electric motors for fans are (asynchronous) of squirrel cage type. Their rotation speed is determined to a few % by the mains' frequency. If doubling the supply voltage, they will burn without doubt, and before having made any useful service.

 

More voltage is possible at motors with a commutator. These serve generally where a quick rotation is needed, for instance at vacuum cleaners. A commutator motor would response to an increase voltage with a higher rotation speed, while the absorbed current would increase only if more torque is demanded (this isn't linked simply with the internal resistance) - though, this is for parallel excitation; a series or compound excitation reacts differently. Mainly the absorbed current defines the losses in a motor, so the increased voltage alone wouldn't increase directly the power losses. Though, expect the commutator to work badly at excessive speed, and be destroyed quickly: that's the weak part of these motors.