Hobart Brothers 6910, Operation And Maintenance Manual With Illustrated Parts List

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8. Test Box
The test box is an optional accessory item used for testing the generator set. All generator sets are wired
to accommodate a test box, however, the box is supplied only when ordered
(Part Number 388318A-1).
A. Description (See Fig. 11)
The test box assembly consists of a rotary selector switch, momentary contact pushbutton switch,
and two, insulated-tip test jacks, mounted in a small metal box. Connection to the generator set is
made through a wiring harness equipped with a 26-contact plug connector which mates with a recep-
tacle connector.
B. Theory of Operation
Wire leads are connected to the electrical circuitry of the generator set at various points and routed to
a receptacle connector, mounted on the engine control panel. They are connected to the test box ro-
tary switch by a plug connector and wiring harness.
The rotary selector switch is wired in such a manner that for any switch position, two pre-selected test
points in the generator set circuitry are connected for testing. The selector switch may be rotated to
any one of 22 positions, however not all positions are used in this installation. An instruction plate
mounted under the switch knob indicates switch positions and component tested in each position.
Normal voltage for each test is also indicated.
Two test jacks are provided for connection of the test prods of a voltmeter. After the voltmeter is con-
nected and selector switch positioned, the test circuit is closed by pressing the pushbutton switch. A
voltage value may then be observed on the voltmeter. This arrangement prevents energization of test
circuitry and equipment for extended periods and allows the operator to reset and adjust the voltmeter
without disconnecting it from the box. For operating instructions, see Sect. 1-3, Para. 3.
1. Test box
2. Cable
3. Plug connector
Test Box Assembly
(Optional)
Figure 11
OM-2028
1-1 May 1/91 Revised
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