MN008006EN Manual
Efective March 2021
NOVA LBS Load Break Switch
www.eaton.com/cooperpowerseries
21
Figure 20.
Connection diagrams for high-potential withstand
testing.
Test 1
1.
Close the switch contacts.
2.
Ground the switch.
3.
Connect terminals 2, 4, and 6 (see Figure 10) together.
4.
Apply proper test voltage (see Table 11) to terminals 2, 4, and
6.
5.
The switch should withstand the test voltage for 60 seconds.
Test 2
1.
Close the switch contacts.
2.
Ground the switch.
3.
Ground terminal 2 and terminal 6.
4.
Apply proper test voltage to terminal 3.
5.
The switch should withstand the test voltage for 60 seconds.
Test 3
1.
Open the switch contacts.
2.
Ground the switch.
3.
Connect and ground terminals 1, 3, and 5 (see Figure 10).
4.
Connect terminals 2, 4, and 6.
5.
Apply proper test voltage to terminals 2, 4, and 6.
6.
The switch should withstand the test voltage for 60 seconds.
7.
Reverse the connections: ground terminals 2, 4, and 6.
8.
Apply test voltage to terminals 1, 3, and 5 for 60 seconds.
9.
The switch should withstand the test voltage for 60 seconds.
Withstand Test Results
The high-potential withstand tests provide information on the dielectric
condition of the switch and the vacuum integrity of the interrupters.
If the switch passes the closed-contacts tests (Tests 1 and 2) but fails the
open-contacts test (Test 3), the cause is likely to be in the interrupter
assembly. Retest each phase individually to determine the failed phase
or phases.
If a switch fails the closed-contacts test, the cause is likely to be a
diminished electrical clearance or failed insulation.
If the switch does not pass Tests 1, 2, or 3, contact an authorized service
center or your Eaton representative.
Note
: Test results for NOVA LBS equipped with the internal
voltage sensing option will be influenced by the source-to-ground
connected sensing capacitor, especially if DC high-potential testing is
performed.
Module Flashover Service
If a NOVA LBS module was exposed to an external flashover, an
inspection process is recommended to assure proper operation of the
switch. Should the NOVA LBS exhibit external flashover attributes
(carbon tracking or discoloration), the following procedure is
recommended:
1.
Bypass and remove the switch from service as described in this
manual.
2.
Confirm the dielectric strength of the switch by performing
High-Potential Withstand Test
. Refer to the High-Potential
Withstand Testing section of this manual.
3.
Inspect the housing and lifting lugs for damage that may affect
electrical and/or mechanical performance. If there is damage to
either the housing or lifting lugs they must be replaced or
repaired.
4.
Insect module for damage to the terminals. Remove any
damaged terminals and replace.
5.
Inspect module for damage to the module conductor rods
(0.63” diameter threaded rods on top and side of module for
affixing terminals). If there is damage to the module rods, the
module must be replaced. Contact an authorized service center
or your Eaton representative.
6.
Inspect the operating rod for damage. If there is damage to the
operating rod, the module must be replaced. Contact an
authorized service center or your Eaton representative.
7.
If no damage is found, clean the module with isopropyl alcohol
and a scratch-free, nylon scouring pad to remove any carbon
deposit.
8.
Before returning to service confirm electrical operation by
opening and closing the switch with a control. Confirm the
dielectric strength of the switch by performing a high-potential
withstand test. Refer to the High-Potential Withstand Testing
section of this manual.
