# Motor test.....



## RKM (Jun 9, 2008)

DIYguy said:


> I was just wondering, I ran my motor a few times from a single 12V battery, after a full rebuild. It seems to run just fine however, I notice the output shaft warms up pretty good after 10 or more minutes of operation. Is this typical?
> 
> Thanks.


 
Hey Gary,

Others with more experience will chime in I'm sure... I don't see why an unloaded motor should heat up significantly at the shaft. You'd better provide a bit more quantified information though "shaft warms up pretty good" won't be good enough to make a diagnosis! What is the ambient air temp and shaft temp? How many amps is the motor pulling?

I hope there is nothing wrong with your motor. Maybe this is normal!?

Rob


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## DIYguy (Sep 18, 2008)

RKM said:


> Hey Gary,
> 
> Others with more experience will chime in I'm sure... I don't see why an unloaded motor should heat up significantly at the shaft. You'd better provide a bit more quantified information though "shaft warms up pretty good" won't be good enough to make a diagnosis! What is the ambient air temp and shaft temp? How many amps is the motor pulling?
> 
> ...


Hey Rob, nice to "see" you. yes, ur right. Will get to it. No time and tools at the moment! 

G


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## DIYguy (Sep 18, 2008)

Here are Time-temperature measurements of my motor. Ambient was about 20C when I started. Measuring device was a Fluke 65, Infrared non-contact thermometer. Motor surface temp at start was about 19.4C. Samples were taken at three locations. The drive end output shaft, the inner race of the drive end bearing, and the inner race of the aux or commutator end bearing. Power was from one 12 Volt Exide starter battery. I couldn't check amp draw because my cheap meter doesn't have DC amp options. 

Conclusions; 

- meter appears to be accurate to about +/- 0.2C based on repeat checks.
- heat is being generated from drive end bearing.
- maximum temperature measured was 37.4 (less than body core temp). 

Other temp checks made were on motor case which went from 19.4 to about 21C over the hour. Also, commutator surface which reached 28.8C.


I will look up bearing specs, but it doesn't seem to be excessive.

OK, not kewl... I just previewed msg and my table turned into a string. String may be interpreted as follows. First digit (2) is time. Second line (21.2) is D/E shaft temp, third line (25.3) is D/E bearing, forth (19.4) is C/E bearing. Pattern repeats. Sorry about that. argh!

Time Temperature – C.
Min
Shaft, D/E
Bearing, D/E
Bearing C/E
2​ 21.2​ 25.3​ 19.4​ 4​ 21.5​ 25.1​ 19.2​ 6​ 21.2​ 27.7​ 19.5​ 8​ 21.6​ 28.3​ 20.1​ 10​ 21.8​ 29.0​ 20.4​ 12​ 23.1​ 30.2​ 20.9​ 14​ 23.4​ 30.9​ 21.3​ 16​ 23.7​ 31.5​ 21.8​ 18​ 24.2​ 31.2​ 22.2​ 20​ 24.6​ 32.2​ 22.9​ 22​ 24.8​ 32.7​ 23.1​ 24​ 25.6​ 33.6​ 24.1​ 26​ 26.0​ 34.0​ 23.9​ 28​ 26.5​ 34.3​ 24.2​ 35​ 28.0​ 36.0​ 25.6​ 40​ 28.2​ 36.3​ 25.8​ 45​ 28.4​ 37.4​ 26.6​ 50​ 27.9​ 36.7​ 26.3​ 55​ 28.8​ 37.0​ 26.6​ 60​ 28.8​ 36.3​ 25.1​


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