Siemens FCV-500 Instructions Manual page 5

4.
Wipe the outside of the interrupters and supporting insulating parts with a clean, dry cloth.
5.
Observe the distance "A
distance "A" which represents the additional compression imparted to the contact pressure
springs from the point where the interrupter contacts make, to the point where the closing link­
age has completely toggled. Distance "A" also represents the maximum allowable erosion of
approximately 1/8" (3mm) of the interrupter contacts. As the contacts erode during the service
life of the circuit breaker, distance "A" will become less. When distance "A" measures within
.030 to .015 (.8 to .4mm) inches, the vacuum interrupter should be replaced. This distance
could be checked at periods of routine maintenance and after periods of high short-circuit
interruptions. The rate of erosion will vary with the application and service conditions. See
contact erosion page 13.
6. Push manual trip button to open breaker.
7 .
Hi-pot each vacuum interrupter while in the open position, to verify that damage has not occured
during shipment. The voltage should be raised gradually, and the contact gap should sustain
27kV, 60Hz a.c. for 1 minute, or 38kV d.c. for 1 minute. If it does not, the interrupter is faulty
and must be replaced.
CAUTION!!
OBSERV E THE FOLLOWING ITEMS WHEN HI- POTTING THE VACUUM INTERRUPTERS.
A. With respect to X-radiation: (No hazardous X-radiation is produced with closed
contacts or with open contacts with rated operating voltage applied to them. )
1)
Do not hi -pot the interrupters at voltages higher than I isted.
tested.
2) Test personnel should remain at least 6 feet (180mm) away from the interrupter being
)
Tests should be performed with normal metal
3
personnel should position themselves to take advantage of shielding provided
by metallic barriers.
B. The circuit breaker bushings and metallic mid-band on the interrupter may retain
a static charge after the hi -pot test, so discharge with a grounded probe before
handling.
1" &
"A2" in figure 3. An average between "A 1"
-2-
&
"A2" will produce
I ic panels installed, and test