# E.M. temp vs efficiency?



## Evilsizer (Jan 25, 2010)

Has anyone tested this? cause i recall reading or hearing somewhere the cooler the E.M. is the more efficient it would be.


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## IamIan (Mar 29, 2009)

The electrical and magnetic properties of the materials in an electric Motor are both effected by temperature ... so yes there is a relationship.

In general most people I have read and talked to only are concerned about the higher temperature end.

For the most part motor manufacture's will provide the temperature specs for their motors... if you stay inside those specs you'll be fine.

But... yes in general... it is best to keep your motor cool.

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Were you looking to try and quantify it to a precise % change in efficiency?


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## Evilsizer (Jan 25, 2010)

IamIan said:


> Were you looking to try and quantify it to a precise % change in efficiency?


not really just wondering how much it is effected as temp increases. what would be a ideal temp to try to keep the motor at while in operation. i guess ideal temp would depend on speed or current pull.


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## IamIan (Mar 29, 2009)

Evilsizer said:


> not really just wondering how much it is effected as temp increases. what would be a ideal temp to try to keep the motor at while in operation. i guess ideal temp would depend on speed or current pull.


The ideal will vary somewhat from motor to motor, depending on the materials they are made from... I would ask the manufacture for the operating temperature specifications for the motor you are considering / planning to use.

A general rule of thumb ... until / unless you get specifications or test results that show otherwise for a specific component ... most components like the same temperatures the human body does ... So very cold is bad , and so is very hot.

During operation electric motors can heat up a good bit ... although they need only a tiny fraction of the cooling system an ICE does... it is still generally a good idea to consider component climate control into your design to some degree... the motor of course ... but also the power electronics , batteries , etc...

I have seen some well designed systems that run cool enough to be fine with virtually no active cooling at all... and I've seen others that the motor produces heat fast enough that without a serious active cooling system it would self destruct in short order.

Remember ... in general ... you will produce the most heat when you are pushing the most kW of electrical power... so , fast accelerations and drag racing like the Killacycle or white zombie are much more sensitive than slower accelerating applications.


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## automd (Feb 5, 2010)

IamIan said:


> The ideal will vary somewhat from motor to motor, depending on the materials they are made from... I would ask the manufacture for the operating temperature specifications for the motor you are considering / planning to use.
> 
> A general rule of thumb ... until / unless you get specifications or test results that show otherwise for a specific component ... most components like the same temperatures the human body does ... So very cold is bad , and so is very hot.
> 
> ...


Yeah! Plus the electrical and magnetic factors of the materials in a Motor are both effected by temperature.


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