# Cooling Jacket



## Csecrist12 (Nov 22, 2019)

I am planning on a electric bike build this winter. I have a K91-4003 Motor and it is not liquid cooled. I was curious if this is going to be an issue or if there is a cooling jack or heat sink that would fit around the motor to better dispurce the heat. Any ideas or? Was curious if I could do a radiator set up having a small water pump run the coolant through the jacket to keep things nice and cool. Any thoughts would be appreciated.


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## remy_martian (Feb 4, 2019)

Impossible to answer: you failed to frame the problem and only succeeded in having people run off to Google the motor info you are sitting on.

Post the motor specs & drawings and tell us how badly you plan to thrash it as far as pack voltage and max/continuous currents.


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## Csecrist12 (Nov 22, 2019)

Not impossible to answer. Just was curious if there was some type of setup regardless of motor. I know for the small RC motors, they have snap on heat sinks to keep those cooler than normal and wasn't sure if a larger, EV motor would have the same setup or a cooling jacket so to say.


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## remy_martian (Feb 4, 2019)

Ah...you're one of those "slap it on and it'll be better and ok" guys. Carry on.


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## Roaminaway (Aug 13, 2020)

Air cooling, with heatsinks may be enough. They have limited potential remove heat, as air is an insulator. The motor will generate most of its heat at the ends, where the bearings are, so make sure the ends of the motor are addressed. 

I have a simple liquid cooling system in mind, for my (purely imaginary, at this time) EV conversion project. In my case, this would be for battery cooling. Here are the components I have in mind. 

1. Heater core (small radiator) from scrapyard

2. 3/8" (10mm) copper tubing, with at least 2 shut-off valves

3. 12 volt magnetic drive centrifugal pump (20-25 Watts)

4. 5" brushless computer fan

5. Coolant expansion bottle

6. Thermal disk - available in a variety of temperature ratings. Voltage is not important, but you will want one rated for 10 amps or more. For a motor, you will want one that closes at about 50 degrees C. For batteries, that will be about 30 degrees C. 

Make your primary coolant loop from the copper tubing. In your case, wrap it around your motor, in my case make a circuit through the battery box. Fit shut-off valves at the ends. It is really challenging to get air-bubbles out of a coolant loop. The bubbles will prevent the centrifugal pump from pushing coolant through the system. When the time comes to connect the cooling system, use a garden hose (on low flow) to fill the copper tube. When a steady bubble-free stream of water is coming out of the other end, close both shut-off valves. 

The plumbing gets connected with the coolant expansion tank at the highest point. These most commonly have a single plumbing connection, so this will be connected to a T fitting. Next is the heater core, with the pump inlet connected just below the outlet of the heater core. The pump outlet is connected to the inlet of the copper tube, and the outlet is connected to the T fitting at the expansion tank. 

The electrical is even simpler. From a 'run' 12 Volt circuit, connect both the fan and pump negative, to the circuit negative. The positive power feed goes to the thermal disk, which will be mounted on the motor, at one end, or the other. The other side of the thermal disk gets connected to the positive of both the pump and the fan. 

When the motor temp gets to 50 degrees C, the bi-metalic strip in the thermal disk will click to the closed position, sending power to the pump and the fan. The coolant circulating and being cooled by the air through the heater core will cool down the motor. When the motor temp drops below 50 degrees C, the circuit will open, stopping the pump and fan. This will effectively cycle the cooling system the same way a thermostat does with its expanding wax pellet, in an ICE engine.


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## Csecrist12 (Nov 22, 2019)

Roaminaway said:


> Air cooling, with heatsinks may be enough. They have limited potential remove heat, as air is an insulator. The motor will generate most of its heat at the ends, where the bearings are, so make sure the ends of the motor are addressed.
> 
> I have a simple liquid cooling system in mind, for my (purely imaginary, at this time) EV conversion project. In my case, this would be for battery cooling. Here are the components I have in mind.
> 
> ...


I appreciate your idea and that's what I was considering. Make your own circuit for whatever application you're needing. I simply acquired my parts from a free trike and it didn't have a cooling system. I like your idea and may try to construct something similar. I wasn't sure if they had something of the natural already designed for any type of motor. I'm still new to the EV stuff so I'm still figuring out what's what.


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