How hot is too hot?

[chunkstyle]

I know this has been asked already but my search of the forum came up short so I thought I'd ask it again. How hot is too hot for a PRS standard stepper motor. I've been running the X rail steppers hard all day between surfacing a new spoilboard and doing some carving. Both motors feel equal in their temp which is hot. So hot that it gets uncomfortable to cup one after several seconds.
I've backed off the tightness of the motor to the rack but they throw some goos heat. It seems this topic has been discussed already but I wonder if anyone could remind me of the answer to how hot is acceptable here?

Thanks

Tim

[rcnewcomb]

From another thread (http://www.talkshopbot.com/forum/showthread.php?t=12432):
Stepper motors run hot when they are moving constantly and fast. A stepper motor can have a 80-degrees C temperature rise (100-degrees actual temperature maximum) before they're beyond their ratings.

50-degrees C is too hot to hold for more than a few seconds, but it is well within the stepper motor's safe zone.

More threads are available ->here (https://www.google.com/#hl=en&sclient=psy-ab&q=hot+motor+site:talkshopbot.com&oq=hot+motor+site:talkshopbot.com&gs_l=hp.3...2601.15705.0.16433.38.33.4.0.0.0.134.1 757.30j2.33.0.les%3B..0.0...1c.kqbm872Zv1M&pbx=1&bav=on.2,or.r_gc.r_pw.r_cp.r_qf.&fp=f0056a833a456726&biw=1671&bih=978)

[chunkstyle]

Thanks for the information and link RC. That's good to know. I've been test cutting some blue foam and realized the cutting speeds would be slower in the wood but the heat still had me worried. Much appreciated.

[myxpykalix]

On occasion i've given myself a "belly burn tattoo" from a hot stepper motor but mine don't get that hot, often enough to get a good idea of why they do.

[WoodMarvels.com]

I know the ShopBot Desktop spindle would get crazy hot - you couldn't touch it! What I would do is put a fan on it and actually let it "rest" for half an hour till it cooled down a bit. I'm told running hot is fine but I want my machine to last a very long time... never noticed the stepper motors getting hot though - yet another thing to check while operating it.

When I was doing my videos in Canada, it was near 0C in the garage - heating was never a problem but here in Oz when I do finally start working on it again, it will be around 30-35C with high humidity. Doubt I'll be pushing my luck and running the ShopBot desktop for hours on end though I know it's more than capable - prefer to be safe than sorry!

Jon

[chunkstyle]

The reading from the provided link was informative. I have some long 3d cutting sessions starting today and the thought of burning up a stepper motor gave me pause. Figured it had to be normal temp rise since there are so many great examples of carved work coming off these machines. Wish I had one of those temperature guns though just to be sure.
I've also been noticing an annoying clicking sound since doing these test cuts without the usual dc and vac noise. Always on a return stroke on the far x rail. Noticed it last night and will pull the motor to inspect before running today. Hopefully it's nothing.

[ssflyer]

Jon,

What spindle is on your Desktop? I have an HSD spindle on my Alpha, and it never gets hot - I can leave my hand on it.

The steppers can get too hot to hold for more than a few seconds, but checking the specs, they are well within the norm.