how hot is too hot

[Claude Boudreau]

Fired up my G-540 with furnished cables and 320 oz-in steppers yesterday. Every things seem to run ok and as stated in some litterature, temperature seem to be at max after about 45 minutes of operation,after 10 minutes of idle temperature drop considerably.
I have a few question concerning heat, my g-540 is enclosed in a well ventilated enclosure and the back is barely warm to the touch, so my worries are about the stepper motor itself. I dont have a infrared thermometer but my hands tell me that burning of the skin could happen (pain start at 45 celcius ) Would 50 celcius be an acceptable operating temperature?
If not is there a way with an G-540 to reduce the heat generated?

And does a motor with no load produce more or less heat?

[awerby]

Steppers can run pretty hot and still be okay. I think they are hottest when holding position; that's when they're exerting maximum torque. The Gecko drives want to be heat-sinked and installed in a box with fan cooling. Heat is related to current (amperage) so if your motors are rated at less than 3.5 amps, you might be able to reduce it by installing current-limiting resistors appropriate for your motors; there's something about that in the G-540 manual (step 4): http://www.geckodrive.com/images/cms...8%20Manual.pdf

[Claude Boudreau]

I had not seen that 70 celcius maximum temperature. I ve order an infrared thermometer this week , they seem too hot to me, to the point of burning skin after 45 minutes of operation. Has anyone else experience this with G-540 and 320oz in steppers?
Although the motor mounting plate and the ballscrew might somewhat serve as heatsink has anyone seen heatsink on stepper?

[Eldon_Joh]

70C outside temps will make for at least 80C internal temps and that's when the magnets start to demagnetize.

if you really want to push the performance, you'll need to press the steel shaft out of the core and slip in a copper one.
or you can drill holes through the case and pull air through the copper windings.. but, metal shavings have a certain affinity for magnets and the airgap is probably .1mm or less.

[john-100]

the maximum motor temperature quoted varies from one manufacturer to another but is usually 70 to 80 C !

on this data sheet its 80C

http://docs-europe.electrocomponents...6b808f8981.pdf


the manufacture will expect the metal work of the machine to act as a heatsink for the motor

if its of all wood construction you may have to reduce the current or add a fan !


unlike servo motors were the motor current depends on the mechanical load

the stepper motor current is always the maximum set by the controller

unless its like the G540 and reduces the current to 70% when idle


John

[JEST]

120 degrees F. (48 degrees C.) is considered scalding and can damage human tissue...

So you can feel burning (uncomfortably hot), and still be well below motor damage temperature.

[Claude Boudreau]

humm,unless this is a typo and if they have the same definition of temperature rise as per NEMA, the max temp here should be 40 degree +80 http://docs-europe.electrocomponents...6b808f8981.pdf
NEMA Insulation Classes
LEESON Electric Corporation - www.leeson.com

the maximum motor temperature quoted varies from one manufacturer to another but is usually 70 to 80 C !

on this data sheet its 80C

http://docs-europe.eambelectrocompon...6b808f8981.pdf the manufacture will expect the metal work of the machine to act as a heatsink for the motor

if its of all wood construction you may have to reduce the current or add a fan !


unlike servo motors were the motor current depends on the mechanical load

the stepper motor current is always the maximum set by the controller

unless its like the G540 and reduces the current to 70% when idle


John

[Claude Boudreau]

makeshift heatsink/motor mount