Stepper motor inside pressurized hydrogen tank

[Saturn-V]

I am sure there are many reasons why it's a bad idea to put a stepper motor/gearbox/clutch inside a tank pressurized with hydrogen, but all I can think of so far is hydrogen embrittlement of the metal components. What other risks/concerns are there? Sparking and explosion isn't a concern because there won't be any oxygen in or near the system.

 

[monkeydog]

I assume you are thinking liquid hydrogen. Consider the CT effects of the motor and the stray spark mixed with the oxidized material on the motor.

 

[3DDave]

How does a stepper motor generate a spark?

 

[Saturn-V]

Good clarification, my application would be in a high pressure Hydrogen gas environment.

I was thinking of possible failure modes, and was assuming any electrical component has the potential to spark or arc

 

[thebard3]

I don't know of any lubricant in the motor bearings and whatever you are moving that would be useful at that temperature, unless you use something dry which is not very effective in rotating assemblies

Brad Waybright

The more you know, the more you know you don't know.

 

[btrueblood]

Not cryo? Can't see any real harm. You need fairly warm H2 (>150C) to start embrittlement, and your stepper isn't likely to be made, or rely on, high-strength steels?