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Running a motor in a vacuum

S

Scorsi

Jan 1, 1970
0
I got into a debate recently regarding motors and the need for air
cooling,
can somebody confirm wether or not a normal motor can run in a vacuum
without overheating and if overheating is a problem, if there is any
type of motor that can run in a vacuum?

thanks Steve
 
C

Clarence

Jan 1, 1970
0
Scorsi said:
I got into a debate recently regarding motors and the need for air
cooling,
can somebody confirm whether or not a normal motor can run in a vacuum
without overheating and if overheating is a problem, if there is any
type of motor that can run in a vacuum?

thanks Steve


Not for more than a few moments. There are special motors designed for running
in a vacuum. They are usually used on satellites. They ARE expensive. The
last one I encountered cost $80,000.00

Bearings are a problem, and heat is removed by conduction.
 
C

CWatters

Jan 1, 1970
0
Scorsi said:
I got into a debate recently regarding motors and the need for air
cooling,
can somebody confirm wether or not a normal motor can run in a vacuum
without overheating and if overheating is a problem, if there is any
type of motor that can run in a vacuum?

A permanant magnet DC brushless motor should survive if you can conduct
enough heat away through the case and it's mounting.

You might have problems with the oil in the bearings though. Might boils off
and become thick.
 
C

Charles Schuler

Jan 1, 1970
0
Scorsi said:
I got into a debate recently regarding motors and the need for air
cooling,
can somebody confirm wether or not a normal motor can run in a vacuum
without overheating and if overheating is a problem, if there is any
type of motor that can run in a vacuum?

thanks Steve

Air is not great as a thermal conductor. A motor can be run in a vacuum by
providing a thermal circuit. Copper is an excellent choice as are other
metals and liquids.
 
J

Jim Stewart

Jan 1, 1970
0
Charles said:
Air is not great as a thermal conductor. A motor can be run in a vacuum by
providing a thermal circuit. Copper is an excellent choice as are other
metals and liquids.

Would the motor idle in a vacuum? Yes.

Would you have to derate the hp of the motor? Yes.

Would you have to be concerned about
lubricants outgassing away? Yes.

If the motor was DC with brushes and commutator,
I think you need to use special brushes. I seem
to remember the military having problems with
generators wearing out the brushes at high
altitudes.
 
J

Jim Stewart

Jan 1, 1970
0
Charles said:
Air is not great as a thermal conductor. A motor can be run in a vacuum by
providing a thermal circuit. Copper is an excellent choice as are other
metals and liquids.

The motor in a turbomolecular vacuum pump
runs continuously in a vacuum.
 
J

Jerry G.

Jan 1, 1970
0
As long as the motor can be properly cooled in a vacuum, there is no
reason that it should have a problem. I would guess that a large type of
heatsink would be the way to go. Normally the air surrounding the motor,
and also having some air turbulence generated by the armature all
contribute to cooling it down in some way.

The other problem is that if lubricants are required, in a high vacuum
many of them would boil down and become thickened, unless they are of a
special type for operation in a vacuum environment. Thickened lubricant
would cause greater resistance for movement.

I know that the motors used in the aerospace industry are extremely
expensive. But, these are made to also be very reliable under very
stressful conditions.

--

Jerry G.
======

I got into a debate recently regarding motors and the need for air
cooling,
can somebody confirm wether or not a normal motor can run in a vacuum
without overheating and if overheating is a problem, if there is any
type of motor that can run in a vacuum?

thanks Steve
 
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