i'm faced with a problem that i don't know how to approach: the appliances we make all use electric motors, and over certain time periods the motor will overheat and stop itself. my goal is to increase the run time of the motor and i don't know where to start. anyone with experience with electric motors that can give me a hand? we are already using a fan built on the shaft that blows a lot of air through the motor while it spins, but apparently it's not enough, and i'm told that the heat source cannot be easily cooled since it's the copper wires itself.

 

You most likely need a stronger motor or more power to it. Are you getting enough juice to the motor?

If an electrical motor is overloaded (accidentally used to drive a load larger than rated or operated at less than rated voltage), the motor will draw excessive amperage in an attempt to provide the necessary power to drive the load. When an overload exceeds its rating, the motor will run hotter than its design operating temperature. This increase in temperature deteriorates motor winding insulation and shortens motor life.

 

[QUOTE]Originally posted by TrojanHorse
You most likely need a stronger motor or more power to it.

 

You can't have both.. that would be a perfect world.

There are far more efficiant motors, but ofcourse costs would be an issue. You can investigate motors with a thicker gauge winding, that should help when the draw on the motor is increased during hard loads

 

Submerge the motor in water while in motion.

 

Well, what is making the motor stop? Usually a thermal reset device. You could increase the thermal switch-off point. Question is what melts next. The coating on the windings has to take the heat without breaking down. You might be able to get a higher-heat rated winding. Or maybe just a more efficient winding (costs more).

Then maybe the permanent magnets go next? That would call for better case cooling (fins, phase change cooling).

Next up, depending on the motor design, is advanced control electronics, you know, don't feed it just a simple sine wave. There's a lot of research going on now to get higher performance out of cheaper motors just by changing this type of control. As mentioned above, higher voltage will run cooler (up till it arcs/shorts!).

You can get some active cooling into the motor through a Peltier cooling device (cooling down through the shaft?) but I doubt you can cool it enough that way.

 

Put a fan in-line with the output of the motor. That would be on the list for me.

 

Have you tried a heatsink?