provides a distribution and control station for all equipment requiring 120
or 208 AC power.
It contains circuit breaker switches, electrically
connected in groups. Each group is connected to one leg of the three-phase
power system, thus providing 3 individual 120 V branch circuits.
circuit breakers function as primary control switches for all 120 V
equipment, and also provide protection for overloaded circuits. The circuit
breaker box is covered by a large door which provides access to the interior
wiring compartment for maintenance.
A smaller door permits access to the
circuit breaker switches.
A circuit identification directory plate is
attached to the inner side of the smaller door.
(7) Blackout relay. The blackout relay is located inside the circuit
breaker box (Figure 3).
It is a single-pole, double-throw, magnetic type
rated at 60 amperes at 120 V. The relay automatically interrupts the van
lighting and receptacle circuits wherever the doors are opened, provided the
main blackout circuit switch is in the ON position. However, the individual
receptacle blackout switches can override the relay when the operating
equipment must be in continuous operation or is not a blackout hazard.
(8) Main blackout circuit switch. The main blackout circuit switch
(figure 3), located immediately below the main power panel controls the
blackout circuit. In the ON position the switch controls the blackout relay
in the ceiling light and receptacle circuits so that these circuits are
interrupted by the door-operated switches. In the OFF position the switch
bypasses the blackout relay, eliminating the function of the door-operated
(9) Door-operated blackout switches.
Three pushbutton type, door
operated, blackout switches (figure 3) are located in the van wall near the
top of the hinged sides of the two side doors and right rear door.
switch is actuated by an adjustable plunger operated by a striker plate
attached to the top of the door. Thus, when the door is opened the plunger
actuates the switch, which in turn trips the blackout relay and interrupts
the lighting and receptacle circuits.
(10) Hinged hood-operated plungers and plates.
contact plungers are located in the edges of the hinged roof sections so as
to aline with striker plates in the mating edges of the hinged floor
sections and side panels.
The plungers and mating plates maintain
continuity of the blackout circuits when the van is in both the expanded and
(11) Receptacle and blackout switches.
Combined receptacles and
blackout switches located in the van ceiling and front walls provide power
outlets for operation of 120 V equipment housed in the van. The integral
blackout switches are used to bypass the blackout feature when the equipment
must remain in continuous operation or does not involve a