Figure 4: Measuring Electrode Resistance
Short Circuit Current-SCI
(Power Supplies)
The Ransburg Multi-Function Meter may be used to
measure the short circuit current of an electrostatic
product. The short circuit current measurement is
important in troubleshooting problems with electro-
static power supplies and applicators. These tests
should be performed when a noticeable decrease
in transfer efficiency occurs. The measured short
circuit current value should be compared to the
value listed in the appropriate power supply or
applicator manual. This comparison indicates if
there are problems with the power source or the
applicator.
Ensure that meter's scale is properly set
for the function in which it is being used. Dam-
age to equipment may result if improperly set.
Operation
1. Set the meter dial to the µA scale (see Figure
5). Plug the probe with two (2) alligator clamp
leads into the side of the meter. Ensure the
meter reads zero. If it does not read zero,
consult the factory for repair of the meter.
2. Place appropriate test resistor in the high
voltage cable socket of the power supply.
See appropriate power supply or applicator
service manual. Be sure it is pushed clear
to the bottom or proper contact will not be
made. Attach one of the alligator clamps to
the lead of the test resistor. Attach the other
alligator clamp to a known true earth ground.
Turn the power supply on. Then trigger H.V.
by the air flow switch or jumper as required
by gun model. (See appropriate service man-
ual for further information.) Be sure that the
power supply lights indicate that high voltage
is being generated. Measure and record the
short circuit current from the meter. This value
should be compared to the value listed in the
appropriate power supply service manual.
W A R N I N G
!
Prior to starting the SCI tests, ensure the
voltage at the power supply is turned off.
C A U T I O N
!
Figure 5: Testing SCI on Power Supplies
Test Equipment - Introduction, Operation & Maintenance
TE-98-01.7
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