Motors Reduce Brushless Motor Heat

[Tony]

I am working on a little project and I need some help. I cannot give specifics, but lets just say that I'm using two different brushless motors, I'm using two different brushless motor controllers, and I need to reduce the heat that is coming from the motors.

The ESC's are no secret. The small one running the smaller brushless motor is a jyqd_6.70 which there is virtually NO information on out there on it. The larger one running the larger brushless motor is the jyqd_V6.3E1. I know the larger one is 500w or about 15 amps. the smaller one is somewhere around 3 amps, but again, I can't find the information on it to confirm.

The motors are 2 pole brushless motors. Very high torque. The small motor is a 700kv motor, the larger motor is 1000kv.

The motors are getting a little hotter than I would like, even under NO load. My question is, what are the possible solutions to reducing the heat these motors output?

 

[RandyDSok]

Typical ESC settings often include battery, throttle, brake, direction & cutoff, timing, and PWM settings. The only two I can think of that even may be close to making some difference would be timing ( which is related to the number of poles the motor has ) and PWM ( typically the differences between inrunner/outrunners )... and I don't know that messing with either would make any distinguishable difference that the automatically detect setting makes with those as long as the ESC is a decent one to start with.

Of course you are already aware of the effects of prop length and pitch... so I'm not going there other than to say decreasing the wattage/amperages is the only real method I know of that can reduce heat without adding a radiator or water cooling.

 

[Tony]

This setup is not exactly for Rc. The controllers have absolutely no adjustment and there are no pads to connect to it somehow and adjust it.

 

[Tony]

But I have thought about the exact same thing as far as timing and PWM being the cause. I have even put these on other actual Rc ESC's where I have adjusted those settings to no avail.

One of the issues that I know of is the motors, which are the inrunner design, have absolutely no cooling holes. It's all passively cooled through the aluminum body and aluminum end caps. And the end caps are epoxied on so I can't take them off. If I could, I think drilling some vent holes in the body would help out tremendously.

 

[murankar]

A high pwm in the esc will cause excess heat. Reducing it will reduce heat and output power.

As for motor heat, all I can think of is using some kind of heat sink. I know on goblins someone created one right on the motor mount. Not sure how to do this and still keep the height down.

 

[Tony]

Heat sink is not an option. The motor is going to be in an enclosed case hence why I need to lower the heat. And with the controllers, adjusting PWM is not an option. Wish it was.

 

[murankar]

Yeah then maybe try a voltage reduction. I know that would drive the Amps up

 

[Tony]

Problem with that would be it would lower the rpm of the motor, and it has to turn a very specific rpm.

 

[RandyDSok]

Alternate energy....

 

[Tony]

lol, I was thinking hand cranking.... I think it's impossible with this current configuration. Might need to look for something that isn't as powerful than these motors.

 

[Smoggie]

If the ESC was adjustable lower timing would in most cases decrease motor temperature. Counter intuitively higher PWM can also cause a slight reduction in motor temperature at the expense of higher ESC temperature.

On the other hand if the ESC has no adjustment and you cant improve motor cooling (by heatsink, ventilation or fan) that really there are no other options other than try a different motor or lowering the load on the motor... or move to somewhere cold

 

[Capn Pete]

This may sound dumb, but is there enough room to add a 'pinwheel' like fan onto the motor shaft? Maybe hand make one out of an aluminum can? Sorta bohemian, but that's how I think!

 

[Tony]

Unfortunately not. The motor is bolted directly onto the unit it is powering and there is no shaft coming out of the back.