Generator Control Box Front Panel Components; (A) Generator Output Monitors (Meters); (B) Meter And Line Switches; (C) Indicating Lights - Hobart 140GT17P Operation And Maintenance Manual With Illustrated Parts List

OM-2029

(1) Generator Control Box Front Panel Components

(a) Generator output monitors (meters)

• Refer to Figure 7. The generator output is monitored by three instruments; a frequency me-
ter (10), a voltmeter (12), and an ammeter (13). The frequency meter is a resonant-reed
type, and indicates frequency of generator ouput alternating current in the range of 380 to
420 Hz (cycles per second). The voltmeter indicates generator ouput voltage in each
phase-to-neutral (A-N, B-N and C-N) or phase-to-phase (A-B, B-C and C-A) as selected by
the meter selector switch (7) and the line selector switch (8). These switches will be de-
scribed below. The voltmeter has a 3-1/2-inch face and the scale is graduated 0 to 300V.
The ammeter is also 3-1/2-inch size and is graduated 0 to 500A. Amperage value in each
of the three phases may be read on the ammeter by selecting the desired phase with
switch (7). Three ammeter current transformers lower ouput load current to a lesser value,
of infinite ratio, which will operate the ammeter movement without damage. The ammeter
dial scale is graduated and numbered so that the pointer will indicate true load current
value rather than the meter movement current.

(b) Meter and line switches

• These switches provide a means of selecting and determining which phase of voltage and
current is indicated on the voltmeter and ammeter and whether the voltage is line-to-neutral
or line-to-line. The meter switch (7) is a four-position, rotary type. Around the switch knob,
the panel is marked and lettered to indicate the three functional positions of the meter
switch. When the knob is pointing straight down, the switch is OFF. The line switch (8) is a
two-position, toggle switch used to select either line-to-neutral or line-to-line voltage to the
voltmeter. The nameplate is also marked to indicate the position of this switch.

(c) Indicating lights

• The function of these lights (9, 11, 14, 15 and 16) is to indicate, to the operator, the abnor-
mal condition of overvoltage, underfrequency, etc., which caused the protective monitor
system to function. Each of the five lights is connected to an actuating circuit within the
memory and time delay module. When one of the circuits is activated, it turns on the appli-
cable indicating light. The light will remain on until the reset switch (5) is pushed. All lamps
in the indicating lights may be tested by pressing switch (5).

(d) Load contactor circuit breaker

• This 2-ampere circuit breaker (4) protects the load contactors against overload.
(e) Protective system circuit breaker
• This 2-ampere circuit breaker (6) protects the 12VDC protective monitor circuit against
overload.
1-1
Page 12
September 30/89 Revised