S&C ELECTRIC COMPANY
s
INSTRUCTION SHEET
663-503
Page 27 of 35
August 14, 1995
Components
No routine maintenance is required for the S&C Micro-AT
Source-Transfer Control. However, operational testing
once per year in accordance with S&C Instruction Sheet
663-590 is recommended to verify proper functioning of
the system.
No mechanical maintenance is required for S&C Pad-
Mounted Gear. However, occasional inspection of the
gear and exercising of the Mini-Rupter Switches is rec-
ommended. In addition, inspection and cleaning—of
insulators and cable terminators in particular—should be
performed periodically, at intervals based on environ-
mental conditions.
The stored-energy operators should be given an exer-
cising consisting of five or more operations at least once
every year, unless normal operating duty provides equal
or greater exercise. With the switches decoupled from the
operators, exercising can be accomplished at any conve-
nient time without requiring that the switches themselves
be operated and, therefore, without requiring an interrup-
tion of service.
The nominal operating life of the stored-energy opera-
tors is 1500 operations (complete close-open cycles), pro-
vided that no more than 500 of such operations are
performed while decoupled.
Place dual-purpose front barriers for switch and fuse
compartments into the “slide-in” position. See Figures 10
and 14. This will provide physical isolation for additional
security if it is necessary to work on the cables connected
to the Mini-Rupter Switch or fuse.
Ç
WARNING
Before cleaning, completely de-energize, test, and
ground the pad-mounted gear. Never use pressure-
sprayed abrasives to clean pad-mounted gear.
Pres-
sure-sprayed abrasives will damage switch and
fuse components.
Ç
DANGER
When access to high-voltage compartments is required
for inspection, service, or repairs, always observe the
precautions below.
Failure to observe these precau-
tions will result in serious injury or death.
1. Access to pad-mounted gear must be restricted only
to qualified persons. See “Qualified Persons” on
page 2.
2. Always follow safe operating procedures and rules.
3. Before touching any device, alway disconnect
switches, fuses, and other devices from all power
sources (including backfeed) and control sources,
test for voltage, and properly ground.
4. When external voltage is used to test any secondary-
side wiring or devices, disconnect all voltage sen-
sors to avoid energizing the high-voltage conductors
through the voltage sensors. To disconnect the volt-
age sensors, transfer the input plug from the input
receptacle to the shorting receptacle. See Figure 3.
5. Always assume that both sets of power terminals
on any switch or fuse are energized unless proved
otherwise by test, by visual evidence of open-cir-
cuit conditions on both sets of terminals, or by
observing that both sets of terminals are grounded.
6. Test for voltage on both sets of power terminals of
any switch or fuse using proper high-voltage test
equipment.
7. After the gear has been completely disconnected
from all sources of power and tested for voltage,
install suitable grounding cables in all compart-
ments.
8. For maintenance of non-S&C equipment, follow the
manufacturer’s instructions.
9. Make certain the enclosure is properly grounded to
the station or facility ground. Do not return equip-
ment to service unless such grounds are properly
made.
NOTE:
Occasionally, low-voltage components may
require maintenance. The maintenance of other low-
voltage components isolated from high-voltage com-
partments may be performed under the safety rules for
equipment rated 600 volts or less. If maintenance is to
be performed on devices connected to the secondary
of a voltage sensor, short-circuit the secondary connec-
tions. A separate drawing will be provided with the
replacement part explaining how to properly short-cir-
cuit the secondary connections.
MAINTENANCE
a
a
These recommendations may differ from company operating procedures and rules. Where a discrepancy exists, users should follow their
company’s operating procedures and rules.
