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temperature alarms for motors?
« on: February 08, 2007, 10:21:10 PM »
so I just fried my first servo motor. maybe the gibs were to tight I dont know. but. regardless I overheated the dang thing and its toast. was wondering if anyone has fitted any of they'r motors with some sort of temperature alarm. something that would beep if the motors got to hot. so when I dont have to babysit my machine while its running. anyone know of a cheap way to rig one up?

Offline DAlgie

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Re: temperature alarms for motors?
« Reply #1 on: February 09, 2007, 01:39:02 AM »
Or run a coolant jacket like I did on the Y axis motors on my router. I use the spindle coolant system, this probably halves the motor temps.
Re: temperature alarms for motors?
« Reply #2 on: February 09, 2007, 11:24:48 AM »
well my servo system is completely sealed for flood coolant. I suppose I could add some nozzles to point some coolant over the motor housings. but something about that seems to me to be risky. you know if the housings arent perfectly sealed.
Ill think about that.

Offline DAlgie

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Re: temperature alarms for motors?
« Reply #3 on: February 09, 2007, 12:43:23 PM »
Yeah, I wouldn't actually spray coolant on the motors I don't think, recipie for disaster. Mine are fabricated aluminium jackets that cover three of the four sides as you see, and I added a small radiator and fan to the system as well.
Re: temperature alarms for motors?
« Reply #4 on: February 09, 2007, 01:42:26 PM »
Well, here's a thought:

Buy as many Thermodisc (www.tod.com->Products->Bimetallic temp switches) "click-style" resettable temp sensors as you have motors.

Strap the sensors to the motors with tywraps. Wire them in series, and use a Mach 3 input pin...or wire them in series with the E-Stop pin.

If any motor gets too hot, it will open (or close...your choice at purchase) and trigger the condition.

When the motor(s) cool down, the Thermodisc will reset (re-click?).

Thermodiscs can be ordered for just about any useable temperature range, say open at 90C and close at 40C...etc.

BTW, I don't work for or have any interest in Thermodisc, Inc. My day job is EE, and I'm simply famiiliar with the product.

-Pat-
There are no shortcuts to anyplace worth going.
Re: temperature alarms for motors?
« Reply #5 on: February 10, 2007, 06:05:19 PM »
seems interesting. but the site doesnt give pricing or tell you where to find a supplier. for some reason they dont look cheap. I can buy a meat thermometer that beeps at a certain temperature for 20 bucks and convert that to beep if my motors get to hot. but Id like a more elegant solution than a meat thermometer sicking outa my motor. any more info on them and what anyone thinks is a safe operating range for a servo motor would be appreciated.
 :-\

Offline Chaoticone

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Re: temperature alarms for motors?
« Reply #6 on: February 10, 2007, 08:25:24 PM »
Pat, you took the words right out of my mouth.

Bathgate, look an McMaster Carr. I would think they would have all kinds of ways, styles to read temp.


Brett
;D If you could see the things I have in my head, you would be laughing too. ;D

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Re: temperature alarms for motors?
« Reply #7 on: February 11, 2007, 01:23:05 AM »
Here are some surplus ones that should work:

http://www.allelectronics.com/cgi-bin/item/THSW-75/765/THERMAL_CIRCUIT_PROTECTOR,_75_C_.html

75C is a good trip temp. for most steppers.

Eugene
Re: temperature alarms for motors?
« Reply #8 on: February 11, 2007, 12:51:44 PM »
looks good. Im curiouse how water resistant they are. Im running full flood coolant also Im curiouse if there is any temp difference for running servo motors instead of steppers. I imagine its about the same.
Re: temperature alarms for motors?
« Reply #9 on: February 12, 2007, 12:19:44 AM »
I would put heat-shrink tubbing completely over the leads and your wire joints, then tape the disc,with electrical tape,  to the hottest part of your motor.  Wrap the disc and wires several times so it's completely covered.  It's no guarantee, but its cheap and easy to try.  As for your motor temp., I would try to find some data on them.