Did you tied your vacuum pump in the air to get rid of the vibrations? Would not the humidity of the pump wear the exposed (visible) wires of the rotor?
Jean Pierre Daviau
2017-10-11 12:11:44 +0000 UTC
Although the gases are ( partly ? ) dissolved in water with the vacuum pump. Your don't think the aspirator pump would exhaust the remaining gas outside of the lab ? This way the pressure of a closed box would be lowered.