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OM2049 2/13
MANUAL DISCHARGE OF CAPACITORS
If the voltage is greater than 1V on any of the capaci-
tors, the capacitor must be manually discharged. With
a suitable capacitor discharge device, such as ground
stick pair (PC3299), discharge the capacitors where
needed per the following instructions:
1. With the control cabinet high voltage compart-
ment doors closed, connect the ground stick pair
ground lead to ground. The most convenient
location is the middle top bolt that attaches the
door center post to the control cabinet frame.
2. Verify the ground connection and ground stick
resistance
levels.
between each individual ground stick tip to either
the GND1 or GND2 ground block in the low volt-
age compartment of the control cabinet using a
multimeter (Figure 20-11). Ensure that the resis-
tance is within the manufacturer's specifications
for the ground sticks.
For PC3299 grounding sticks, the valid range is
80 to 125 ohms per stick.
Hazardous voltages are present in this equipment.
Avoid touching any energized equipment when
the door to the low voltage area is open. Failure to
do so may result in personal injury and equipment
damage.
FIGURE 20-10. CAPACITOR TERMINAL POLARITY
Measure
the
resistance
3. Discharge the relevant capacitors. Open the
door(s) and place one grounding stick on one of
the positive (+) capacitor terminals and the other
on the diagonally located negative (-) terminal.
Refer to Figure 20-10 and Figure 20-12. Attempt
to minimize the time between application of the
positive stick and the negative stick so that the
current flow will be positive to negative rather
than either to ground. Leave sticks in place until
capacitors are discharged. Refer to Figure 20-
12.
NOTE: On the capacitors located behind the door
post, it is difficult to access diagonal terminals on the
same capacitor. If using adjacent terminals, use care
to keep the tips separated while discharging or else
use a positive terminal on one capacitor and negative
terminal of the adjacent capacitor on the same bus
bar.
For PC3299 grounding sticks, the discharge times
from 2000 volts are:
• 15 seconds (maximum) for 2 capacitors
• 75 seconds (maximum) for 10 capacitors
Safety - Section 20
Page 20-19
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