Motor Heat Sinks

[EvilSpirit1]

Since heat is the big enemy of electric cart components, I would guess anything that we could do to dissipate the heat from operation can't be a bad thing. Anyone try to make a heat sink for the motor? I'm thinking about taking some 18ga aluminum and bending up some 1/2" angle pieces and either attaching them to a thin sheet to wrap around the body of the motor, or just use some band clamps to attach them directly to it. I used to do this to the oil filter on small engines to help keep the oil cooler.

Any thoughts? The aluminum should transfer and dissipate the heat well, and if nothing else the increased surface area can't hurt. It would be easier than trying to install a fan, or could be used with a fan for increased efficiency.

[Newbuggyboy]

Originally Posted by EvilSpirit1

Since heat is the big enemy of electric cart components, I would guess anything that we could do to dissipate the heat from operation can't be a bad thing. Anyone try to make a heat sink for the motor? I'm thinking about taking some 18ga aluminum and bending up some 1/2" angle pieces and either attaching them to a thin sheet to wrap around the body of the motor, or just use some band clamps to attach them directly to it. I used to do this to the oil filter on small engines to help keep the oil cooler.

Any thoughts? The aluminum should transfer and dissipate the heat well, and if nothing else the increased surface area can't hurt. It would be easier than trying to install a fan, or could be used with a fan for increased efficiency.

I could be interested in one of these.

[Mooncarter]

Interesting idea. However I would think that a hot electric motor would be an indication of a problem.

I would be inclined to think that 60 or 70 years ago they would have done this for that problem if needed.

I'm not an expert on this, just throwing it out there to be discussed.

Good question.

[EvilSpirit1]

Electric motors commonly have cast in cooling fins.

[Mooncarter]

What is the application for this motor?

AC, DC, variable speed?

Voltage?

[Newbuggyboy]

FYI

[bronsonj]

You would need a lot of cooling area. I thought of taking some CPU coolers and attaching them to the sides of the motor to keep it cool, but decided they were not enough.

Electric golf cart motors don't like to turn slow, lots of heat build up. Some also don't like fast, I think PDS didn't. But if you put fins on it and/or a cooling fan that may help. There is a lot of mass in that motor though, so a 1/2" fin is probably not tall enough.??

[EvilSpirit1]

Originally Posted by Mooncarter

What is the application for this motor?

AC, DC, variable speed?

Voltage?

No idea. Does it matter? It's an electric motor with cooling fins to help with temperature control. Many have internal fans to do the same.

I'm not trying to rewrite history here. It's a well known issue that under some conditions our cart motors get warm or hot. This heat shortens the life span of the motor. I just asked if anyone has tried to create a heat sink using cooling fins attached to their cart motor.

We commonly add heat sinks to controllers to dissipate heat. We know that heat kills electronics. I've worked on electrical cabinets that had their own A/C units to keep the servo controls and ECM's cool. So why not use some cooling fins to help cool the motor?

[EvilSpirit1]

Originally Posted by bronsonj

Electric golf cart motors don't like to turn slow, lots of heat build up. Some also don't like fast, I think PDS didn't. But if you put fins on it and/or a cooling fan that may help. There is a lot of mass in that motor though, so a 1/2" fin is probably not tall enough.??

Just throwing the 1/2" number out there as an example. I'm thinking the amount of and temp of the airflow across them would dictate an optimum height or spacing. Obviously if someone wanted to take a course in thermodynamics they could probably come up with a height ratio to width of opening, yada, yada, yada. I'm going under the theory that while the motor works reasonably well under most conditions, there may be a way to help it cool on the cheap.

[JohnnieB]

In a nutshell, the DC traction motors, both series and sepex, we use in carts operate from about 50% to around 85% efficiency depending on RPM, so from 15% up to half of the amps that pass through our motors are converted to heat energy. The AC motors used in some cart also have an efficiency curve, but I don't know its shape or what the efficiency range is.

The temperature a motor reaches is the end result of accumulated heat energy, so the more heat energy that can be removed from the motor, the less the temperature rises and the cooler the motor runs, the longer it lasts, barring abuse and mechanical failures.

My motor gets mighty hot mighty fast when I run my cart at its top speed with a 42V battery pack on 17" tall tires (28.5MPH @ 7000RPM) because the field map I'm using drops the field amps far below the 3A minimum recommended by D&D. Prevention being the first line of defense and not needing the top 3.5MPH, I dialed the max RPM back so the motor doesn't get into the dismal efficiency range quite as far and runs much cooler.

I've kicked around the idea of adding some copper fins (copper has better thermal conductivity than Aluminum) and fans, but also gave some thought to liquid cooling.

Yurtle came up with a red-neck cooler, wrap a towel around the motor and drip water on the towel. Basically an evaporative cooler for a motor.

My idea was to wrap soft copper tubing around motor and run a non-corrosive liquid (cooking oil) through to tubing out to a radiator made out of the finned copper piping used in baseboard heating.

Bottom line is that anything that will help remove the heat energy from the motor will help it last longer.