Motor Cooling Questions: ANSWERED.

(Brammo) Secrets of (Empulse) Universe: REVEALED.

When Brammo announced the Empulse with a liquid cooled motor I started to suspect I was onto something with all this cooling hoo-haa I’ve been obsessed with.  It was Brammo, with their little cooling fan, that got me thinking it was a good idea in the first place.  Add to that what I learned about motor heating and building resistance and decreasing efficiency.  The reaction I got from people who actually understand this was, well, YEAH…  heat is bad. duh!

That’s all good, but I want proof.

It was pretty much unimaginable to me that this wasn’t a known quantity, and one of the guys on rattled off an equation that sort of explained it-  the numbers are pretty simple.  An engineer really doesn’t need to run a test, Iike I would, they can run the numbers.

Then, I saw this.  The Parker Electromechanical Automation Blog.  More specifically, this.  The Parker MPP motor used for the Brammo.  To wit: The MPP powering the bike features Parker’s patent-pending internal cooling – a technology that increases the continuous torque output that virtually eliminates the peak region of the motor.

MOST importantly, I got me a graph.

You KNOW how I love me a good graph.

And HERE, my friends is the key to the Secrets of the Motor Cooling Universe. “Calculating Winding Temperature“, with numbers and graphs.  There, buried in the data and calculations, is the secret of the awesomeness of the cooling system designed into these motors.  In a normal motor the heat goes from the winding to the case, then to “ambient”- the outside environment.  Even if you wrap coils around the case, you’re going through the entire assembly.  These motors cool from the windings directly, eliminating the case.  That makes it cool faster.  If it cools faster, it doesn’t build up so much thermal momentum.  Also, your ambient temperature is having a direct, not intermediate, effect on the windings.  They’re staying cooler- more even- at the outset.

Now for the, (oh, jeeze…)  cool part.

The MPP series motors on the Parker Hannifin site are listed as liquid cooled rotary servo motors…  could this be the Holy Grail?  An off-the shelf servo motor for the next generation of awesome awesomeness?

And here is my wild guess on the motor in the Empulse.  The Parker Haniifin MPP SERIES MPP2708N- 1600 RPM,  20.3 kW,  26.6 HP.

Or not. “Parker will customize any MPP/MPJ motor to meet your specifi c system requirements. Parker does customs like no one else. We are specialists at customs, offering unrivaled custom motor solutions and support.” (Brammo: “Gimme a 20kW motor that runs at 6000 RM yo.  About a thousand of them, how’s that?”)


2 responses to “Motor Cooling Questions: ANSWERED.

  1. Stepper motors are used for different kinds of applications ….

    But you’re absolutely on the right track about internal cooling. FWIW the EV1 motor has two liquid cooling systems. FWIW heat is the issue which has been plaguing the TTXGP folk.

    FWIW the Remy motor that MotoCzysz is using (see my recent article about their joint venture) uses internal liquid cooling.

  2. Right- first, I made a little mistake I think- it’s a servo motor, not a stepper motor- but I think that’s academic. It does fall under the MPP product category though, and it’s not a stretch to consider it for a baseline design for a motorcycle modification.


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