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What are good MMS #'s?

What are good MMS #'s?

Old 10-06-2013, 05:42 PM
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Default What are good MMS #'s?

I am starting to look into 17.5's to run in my sc10.2. I have noticed a few people that are sellings motors and that have the means to, include 3 sets of MMS #'s. Usually like 23.5, 22.7, 23.2(pretty sure those sound bout right) What are good numbers? Do the numbers change for different size motors? What do these numbers mean? Thanks for any info
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Old 10-07-2013, 01:07 PM
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I assume the MMS you see is millimeters, but I am not sure.

As for the sets of _____ that they have with a motor, some people will have more than on stator which is the part of the motor with wound wire on it, different turns will be rated as your example of 17.5, which is "stock" winding.

This page by novak is a chart to compare the turns they offer and maybe give you some idea the big picture.

You can see that as the number goes down on the turns the KV value goes up. A higher KV will have a higher RPM at a given voltage and also produce less torque, so you have to gear for each one on a case by case basis to keep from overheating. A higher KV will take a lower gear ratio to run safely. I am sure somebody else can explain it all better, I just hope I am not causing confusion.
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Old 10-07-2013, 01:42 PM
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lbenton-thnks for the info. I believe the "MMS" stands for "motor measuring system", kinda like a dyno-jet for full scale cars. Im sure if the people that are selling the motors post their "MMS" #'s then they must be good or they prob wouldn't post them. It seems like having consistent #'s is good, but didnt know if each different "turn" or "kv" motor should produce a specific range? What would that range be for different motors or at least 17.5?
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Old 10-07-2013, 05:14 PM
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The MMS numbers are probably from one of these or similar. As the page describes it measures the resistance of the stator windings, there are 3 windings in a 17.5T brushless motor thus 3 numbers for results.

Lower resistance numbers are better. Will vary by turns, lower turns will be lower resistance.

Then there is rotor magnetism if interested, probably more important. The guys above have this one to measure rotors.

Fantom sells a unit with both measurements in one here.
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Old 10-07-2013, 05:22 PM
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Thanks Dave. Pretty much exactly what I was looking for.

Last edited by Dave H; 10-09-2013 at 05:19 PM. Reason: oops wrong button! no change
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Old 10-09-2013, 05:19 PM
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Originally Posted by KAWIDAD
Thanks Dave. Pretty much exactly what I was looking for.
No problem. I'm pretty much retired, but still like to help a teammate out!

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