REPAIR OF HIGH VOLTAGE SECTION
Section I. HIGH VOLTAGE CABINET
seals or replace damaged one, tighten loose hardware or
The high voltage cabinet is a weatherproof housing with
replace any that is missing. Replace broken
two hinged front panels (upper and lower), two removable
or cracked insulating barriers and cable supports.
rear panels (upper and lower), and a transition area. The
cabinet houses the load break switch in upper front
3-3. Inspect and Replace Lightning Arresters
section, three lightning arrestors and a heater in lower
front section. The rear panels allow access for connecting
the primary conductors up and through the bottom to the
connectors on rear of load break switch. The transition
Lightning arresters are live equipment. No
area provides a housing for the connections to the
work should be done or contact made with
primary sides of the transformer from load break switch,
them while the line is energized. (Current
with access panels front anti rear. All panels are secured
flows through an arrester from line to
with hex head bolts. The front upper panel allows for a
ground. A potential gradient exists that is
visual inspection through two non-reflecting windows,
hazardous if handled while energized.
and operation of switch with panel closed. The switch
operating handle socket is covered and has a lockable bar
Inspect insulator for damage caused by
to prevent unauthorized switching.
external flashover. If cracked or burned, replace.
Inspect for damage to apparatus protected
3-2. Enclosure Inspection and Repair
by or near arrestor.
a. Inspect exterior and interior for dents, holes,
b. Replace. Refer to figure 2-13.
scratches, bends. panel alignment, weather seals
and other damages.
Make sure lines are de-energized, and load
b. Inspect interior for loose or missing hardware,
breaker switch and main circuit breaker are
broken or cracked cable supports or insulating
(1) Remove line connection at top of arrester.
c. Straighten dents and bends, fill holes, clean,
(2) Remove ground connection on bottom of arrester.
prime and repaint bare metal, cement loose weather
(3) Loosen nut of clamp holding arrestor, and remove
(4) Replace or install in reverse order.
Section II. LOAD BREAK SWITCH
auxiliary blade. When the switch is opened the
3-4. Load Break Switch Inspection and Repair
auxiliary blades contacts are the last to part and will
a. Description. The load break switch is a
initiate all arc in the chute. The hot arc releases gases
manually operated, triple pole disconnecting switch with
from the last plastic chute in such volume that the arc is
an integral interrupter that has the capability of
blown away from the rapidly moving auxiliary blade and
interrupting transformer magnetizing and load current
cooled by contact with the larger area of tine chute sides.
within its rating. It has a manually charged, spring stored
After the arc has been extinguished, the blade will
energy operating mechanism capable of closing the
continue to open producing a sufficient air gall to
switch against maximum rated short circuited current.
isolate the termiillali
The operation of the switch is accomplished by manual
rotation of the detachable operating handle through an arc
(b) Switch Inspection Refer to TM 5-6120-250-12.
of 180° The switch has a positive closing and opening
operation supplied from the stored energy of springs. The
(c) Switch Repair Refer to Checks and Adjustment
interrupting ability of the switch is accomplished by the
use of an arc chute type interrupter and an