ABB AMVAC Installation And Operation Manual page 21

OPERATION, INSTALLATION, AND MAINTENANCE
P C A
RIMARY IRCUIT
The primary circuit requires visual inspection of hardware, low-frequency withstand voltage testing to insure vacuum, and
lubrication during routine maintenance.
All insulation material should be clean and free of structural cracks. Some minor cracks are inherent in the insulation
material. Inspect for structural cracks and replace damaged parts.
Dirt or dust may create a dielectric path to ground on the insulation. Remove dust and dirt with a clean, lint-free cloth.
Apply distilled water to the cloth to remove any difficult dirt. DO NOT return the circuit breaker into service until the
insulation surfaces are completely dry.
Lubrication on the primary contacts should be inspected during routine maintenance. Use NO-OX-ID special grade-A
grease for the lubrication of primary contacts.
To verify the integrity of the primary insulation, perform the following low-frequency withstand voltage test:
1. Close the circuit breaker (no control power supplied).
a. Connect the high potential lead to one pole.
b. Ground the remaining poles and the circuit breaker frame.
2. Start machine with output potential at 0 (zero) VAC.
3. Increase the potential to the required voltage (see Table 3; note that new condition test is a factory test only and is
not valid for field condition tests).
4. Hold for one minute.
5. Decrease potential to 0 (zero) VAC and turn off machine.
6. Repeat for the remaining poles.
A successful withstand indicates satisfactory insulation strength of the primary circuit.
High voltage applied across an open gap in a vacuum can produce X-radiation. No radiation is emitted when the
breaker is closed, since no gap exists. Also, when the breaker is open to the specified contact spacing in ser-
vice or tested within the voltages specified, X-radiation at one meter is below the level of concern. A danger
could exist at voltages above or contact spacing below that specified.
:
SSEMBLY
(Pole)
Rated Max Dielectric Test
Voltage Value, 1 Minute
Dry AC rms
New Condition
reference c37.06
4.76kV
8.25kV
15kV
27kV
Table 3: Primary Low-Frequency withstand
Test Voltages
1VAL050601-MB Rev C
Dielectric Test
Value, 1 Minute
Dry AC rms
Field Condition reference
c37.20.2
19kV 15kV
36kV 27kV
36kV 27kV
60kV 45kV
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