Re: [CAD_CAM_EDM_DRO] Re: My stepper getting hotter

On Tue, 25 Jun 2002 23:44:56 -0000, you wrote:

>You are wanting two opposite things; a cool motor and lots of speed.
>You can't have both. Step motors are designed to run hot (85C) when
>they are used with a power supply voltage needed to generate maximum
>speed. That is why they have teflon wire insulation instead of vinyl.

I have a Dynamax Servo motor here that I use as a spindle motor on my
small Taig mill and was worried about it getting very hot (75C). I was
pleasantly surprised when I checked with them. They reckon they are
safe to 150C, before the insulation starts to break down, and over
250C before the magnets loose their magnetism!!

I never did find any manufacturers specs that include maximum
temperatures for steppers. Sanyo Denki merely say "Do not touch in
operation, may reach high temperatures". MAE just give an ambient
operating range of 20-40C.

May be a question for you to ask next time you speak to one of them,
I'd certainly be interested in the answer.

I still fitted a fan & shroud to the servo though - stops me burning
myself on it <G>.

My steppers shut down after 1min of no steps, the axis is still locked
due the fine pitch of the screw, but I could see that being a problem
with machines using coarse pitch and belt reduction drives. They
barely get warm, but I'm only driving them at half their specified max
voltage - It's enough for my needs at the moment ;)


Steve Blackmore
--
Pilot Consultancy Limited ***** Computer Consultants
Telephone 01744 752256 Mobile 07831 768478
Email: steve@... WWW: http://www.pilotltd.net