Is there a practical limit to the output of any electric motor if the power supply can increase according to the motor's attempted output?

To a very minimal extent. Your max RPM will be reached at full voltage, plus whatever current is required to ovecome friction sources. The rpm will sharply drop as you add a load, unless more current is available, at which point it will begin drawing more to compensate.

The rpm is unlikely to increase- it may slightly with a higher voltage, but then you may end up burning out the windings since they have a set resistance, and you would be running a higher wattage to them than they're rated for, unless you governed the current accordingly. How much faster do you want it to go? What kind of application?

We may be able to offer a safer solution.

Yes, there is a limit. However that limit is often well above the rated limit of the motor. If you don't start thinking about it too hard you can identify the points of failure (the practical ones) as: - Resistance of the windings.

All conductors (don't think too hard) have resistance. As you increase voltage across the windings, the power that the wire has to dissipate (heat) increases. At a certain point, the windings will melt.

The formula to determine the resistance of a given conductor is; R = (4pL) / (pi*d^2). Where R = resistance, p = resistivity (depends on the matl. ), L = length and d = diameter.

With this information you can determine how much the windings will heat at a given voltage. After this, it gets much more complicated to determine 'exactly' when the windings will fail. Think about the cooling effect of a rotor revolving through air @ a given rpm, include other factors such as ambient temp, then take a Tylenol a shot and a nap.

- Bearings. Spin 'em too fast or put too much of a lateral load on them and they'll fail. - Balance.

Nothings perfect. Eventually it will shake itself apart. If you want a DC motor to spin faster (up to its upper limit) or provide more torque, give it more power.

If it doesn't melt through the workbench, it's 122% safe.

Yes, there is a practical limit. At some point your motor is going to burn up. As an example, I once built a windmill hazard for a mini-golf course.In it was an ac motor that I thought was supposed to be 120V.

It turned out to be 12V. When turned on, it ran, very very fast. The problem came when it started to overheat and smoke, and within about 5 seconds of power on it caught fire.

So, be careful with major overvoltage on motors. The effects can be spectacular. Enjoy, Ray.

What you can increase is the supply voltage. This causes indeed higher RPM in relation to the architecture of the motor. As a second effect the heat generated is higher and higher up to a point it can't be dissipated efficiently.At a certain point the insulation of the winding's wires melts ensuring short circuits between windings reducing the overall electric resistance.

The motor slows down and the current increases. To this increase corresponds more heat generation and so on up to the moment where some copper wire melts, the electric circuit is than interrupted and the motor stops to function.In the meanwhile fire can eat the motor itself and you have a hot black brick only, if you are lucky. Where is the limit is the question... it is not so long after the moment the heat causes the first short circuit between windings.

This can't be calculated. We are not dealing with a single linear wire but with a very complex structure, rotating and with to much possible variables in action. Predictions can be made by studing single cases of motors.

No general rules can be postulated. BTW often motors will stop working before all this due to distruction of the brushes too...

I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.