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Unusual Operating Conditions
Low Current
If the pump current reads lower than normal for the pressure (see
the preceding figure), the discharge may have been extinguished.
To check for the pump being "out of strike" (discharge extinguished),
remove the magnet and observe the residual current. If the current is
the same with and without the magnet in place, no discharge exists in
the pump.
a
b
High Current
If the pump current reads higher than normal for the pressure (see
the preceding figure), look for:
a
b
c
d
Miniature and 2 l/s VacIon Pumps User Manual / 87-400-044-01 (E)
To restart the discharge, tap the pump body with a soft plastic
tool, or heat the pump body locally with a small soldering iron.
This should liberate surface gas within the pump and restart the
discharge. NEVER strike the pump with metal hand tools.
If the magnet strength is below its rated level, the pump
discharge and speed will be reduced and the discharge may
extinguish at a pressure below 1x10
Breakdown of the connecting high-voltage cable. Repair or
replace.
Ohmic breakdown in the control unit. Repair according to the
control unit instruction manual.
Shorting of anode support insulators, caused by a flake of
titanium compound. Tapping the pump, as described in step a) of
the preceding paragraph, may correct this condition.
Field emission current from fine whiskers formed on the pump
cathodes. Hi-pot the pump by applying 10 to 14 kVac at
20 to 30 mA for 5 to 20 seconds.
Instructions for Use
Unusual Operating Conditions
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