Electric Motors in space

[stardelta]

Hello Guys, I have popped over from the Motors and Controls forum in the hope I can perhaps get some information and advice from you. I work for a large Electric motor repair company in the UK and I have been asked, well ordered! to compile a feature for our in-house magazine. The subject I am researching is Electric-motors used in space and space vehicles. Any links or information would be greatly appreciated as I am finding it difficult to find anything on the Net.

Many Thanks

 

[aeroinvent]

I think rover used on the moon used electric motors. Also the mars robot(I forgot its name) used electric motors, recharged by solar panels.

 

[GregLocock]

Big problems I can see are lubrication (use ceramic ball bearings) and heat buildup, with no air to waft the heat away.



Cheers

Greg Locock

 

[stardelta]

I have heard a comment that the windings on some motors are formed from gold wire as opposed to the usual copper and are cooled by liquid nitrogen.....can anyone comment on this??

 

[scooter911]

I'm a mechanical guy, but here goes. I am aware of three problems we have run into here testing electrical motor in big vacuum chambers. Two have been pointed out, heat dissapation and lubrication, the third has to do with something called "Corona". It's the increased ability of a electrical potential to jump a gap and cause a short during certain ranges of vacuum. If I am correct there are reasons for gases to be generated inside of a motor while running, these can cause localized increases in the vacuum level to bring you into the "corona region" and cause shorting. I think all our motors are either put into a vented can or DC and 80 volts or less. As for the other problems you have to find a way of cooling the motor and used either a low vapor pressure grease or greaseless bearing. You can try

http://www.nasa.gov,

hope this helps a little.

Scoot

 

[valhalla]

Here's a page with a few more problems in using motors in space, mainly focusing on designing circuits to resist thermal breakdowns. The company that posted this does a lot of work with NASA and the large prime contractors so the info should be reliable.

(

http://www.empiremagnetics.com/articles/space_applications.htm)

On a bit more technical front, NASA has prepared a guideline called the Space Mechanisms Guidebook. Some of the book is available publicly online. Some is ITAR restricted so if you really need it you will have to submit an application and prove that you are a US citizen, that you work for a US based company and a few other things that are a pain so if you don't really need it, don't grab it. The public version is available at the following URL.

(

http://www.grc.nasa.gov/

http://WWW/spacemech/contents.html)

The public version has information about a lot of mechanisms including motors, although information on lubricants, bearings and a few other areas related to motors are not contained in the motor section, so you may have to selectively search the document. Cheers

Brian Lewis
The Aerospace Corporation

http://www.aero.org/