PCM-2 Manual.pdf - Voss Associates

NOTE:
If more than a single arc occurred during the test interval then that channel
of the probe has failed its high voltage check and can not reliably function
in the PCM-2 instrument without further rework to increase its operating
voltage capability. If the probe assembly has not at this point been faced
with its mylar covering, it can be removed from the test fixture and visually
inspected for evidence of dark carbon pin-points or discoloration. These carbon
spots are often deposited on the inner surface of the probe chamber and/or at
the corona doped areas within the chamber resulting from and marking the
exact point of the arc discharge. Some arcing can occur as a result of
improperly or insufficiently doped wire support tips, anode wire spring tips
and/or high voltage solder joints. A probe which has failed the arc test
can often be remedied by first cleaning the discolored area or burned corona
dope with lacquer thinner and then touching-up these discharge pin-point
areas with an additional coat of corona dope. Depending on the amount of
touch-up needed, a one to four hour corona dope curing interval may be
required prior to retesting the probe. If a burned arc discharge area is
evidenced on a surface of insulating PTFE tape, an additional layer of tape in
that area will be required. Removal of the completed probe's mylar face is
required to perform these carbon discharge point inspection and touch-lip
corona doping procedures noted.
5. If the probe is noticeably arcing but its visual inspection reveals no evidence
of burned pin-points or discoloration, then an additional visual test, using
the smoked plastic panel, will need to be performed to isolate the cause of the
arc(s). In this case the smoked plastic panel takes the place of the mylar face
being placed between the probe chamber gasket and the chamber ring (removal
of the probe clips and mylar face is required for fully assembled probes). The
probe must then be adequately sealed by clamping the probe together. Again
hook up the P-l 0 gas supply hose (regulated it 1 psi pressure and 200 cc/m in
flow) and vacuum pump hose to the probe and cycle the pump to evacuare the
air in the chamber. A 1 to 2 second pump "ON" interval for about !J- to 6 cycles
will suffice to evacuate the chamber of air without causing the plastic face
panel to over-deform and break. Repeat the high-potter arc test with the
lighting around the probe darkened sufficiently for the arcing to become visible.
Identify the point(s) of arcing, remove the ciamps and smoked plastic face
panel and remedy the cause of the arc(s) as previously noted.
6. Repeat steps] thru 4 above for all previously failed and reworked probes.
LEAK TEST
Equipment needed:
1. PCM2 OPT12 or PCM 1B OPT18, Gas Manager Assembly with the following modifications:
- A 0.005" orifice (FGMl50) has been plumbed in series with the
"Purge lnlet" solenoid valve.
- The "Outlet" solenoid valve has been disconnected from port "P2"
of the manager's pressure sensor transducer.
- A 1/8" ID "return" hose with sealing quick-connect fitting (FGPL3 ]) connected
to the pressure transducer"s "P2" port.
10429-A525/PCM-2 Oet. Voltage & Leak Test Procedure/Revision/March 1994