39
Instruction manual
| Types SDV-R and SDV-R-AR distribution circuit breakers
Sub-assembly
Item
Inspect for
Primary power path
Vacuum interrupter
1. Cleanliness.
2. Contact erosion.
Note:
Perform with manual-spring checks.
3. Vacuum integrity.
Note:
Perform with high-potential tests.
Vacuum interrupter contact resistance
1. Record contact resistance with contacts
closed and check at each maintenance
interval to monitor condition.
Vacuum interrupter operator mechanism
Cleanliness
1. Dirt or foreign material.
Fasteners
1. Tightness of nuts and other locking devices.
(Stored-energy) manual-spring check
1. Smooth operation of manual charging,
manual closing and manual tripping.
Lubrication
1. Evidence of excessive wear.
2. Lubrication of wear points.
Electrical controls
Wiring
1. Mechanical damage or abrasion.
Terminals and connectors
1. Tightness and absence of mechanical
damage.
Close and trip solenoids, anti-pump relay and
auxiliary switches
1. Automatic charging.
2. Close and trip with control power.
High-potential test
Primary circuit-to-ground and between primary
disconnects
1. 60-second withstand.
Control circuit-to-ground
1. 60-second withstand.
Insulation
Barriers and all insulating components
1. Cleanliness.
2. Cracking, crazing, tracking or other sign of
deterioration.
Space heaters
Space heaters
1. Correct operation.
Table 4: Periodic maintenance and lubrication tasks
Checks of primary power path
The primary power path consists of the
vacuum interrupters, the fixed-end and
moving-end connections to the enclosure bus
system and the roof-mounted bushings.
These components must be checked for
cleanliness and condition. The vacuum
interrupters must also be checked for vacuum
integrity.
Check torque of the bolts that secure the roof
bushings to the top plate of the circuit
breaker. Torque should be in the range of 20-
25 ft-lbs (27-34 Nm).
If a bushing has been removed or is being
replaced, tighten bushing mounting bolts in a
cross pattern, progressively increasing torque
from one-third to two-thirds to full torque.
Use anti-seize compound (Loctite* 77164 or
77124 nickel anti-seize) on the threads of
the roof studs to facilitate future removal of
a bushing should it become necessary.
For connections between the bottom of the
bushing and the bus bar, torque the 1/2-13
SAE grade 5 steel hardware to 50-75 ft-lbs
(80-102 Nm).
For connections between the bus bars and
the pole heads and connector box of the
operator, torque M12 x 1.75 grade 8 bolts to
52 ft-lbs (70 Nm).
Some test engineers prefer to perform the
contact-erosion check during the manual
spring-charging check of the stored-energy
operator, since charging of the springs is
necessary to place the contacts in the CLOSED
position. Also, the vacuum integrity check is
usually performed in conjunction with the
high-potential tests.
These instructions follow the
recommendation that these tests contact
erosion/manual spring-charging check, and
vacuum integrity/high-potential tests) will be
combined as described.
* Loctite is a registered trademark of
Henkel Corporation.
