Miller Electric Big Blue 502P - Manual (Page 25)

OM-491 Page 21
5-2. Description Of Front Panel Controls (See Section 5-1)
Engine Starting Controls
1
Magnetic Shutdown Switch
Use switch during start-up to bypass engine
shutdown system. System stops engine if oil
pressure or fuel level is too low or coolant tem-
perature is too high.
2
Starting Aid Switch
Use switch to energize port heater for cold
weather starting (see starting instructions fol-
lowing).
3
Engine Control Switch
Use switch to start engine, select engine
speed ( if unit has auto idle option), and stop
engine.
In Run position, engine runs at weld/power
speed. In Run/Idle position (optional), engine
runs at idle speed at no load and weld speed
with load applied. Turn to run position if using
optional auxiliary power plant.
To Start:
Above 325 F: turn Engine Control switch to
Start while pressing Shutdown switch. Re-
lease switches when engine starts and en-
gine indicator lights go out. Do not crank en-
gine while engine is turning.
Below 325 F: turn engine control switch to
Run/Idle position. Press Starting Aid switch
for 60 seconds. While still pressing Starting
Aid switch, press Magnetic Shutdown switch
and turn Engine Control switch to Start. Re-
lease switches when engine starts and en-
gine indicator lights go out. Do not crank en-
gine while engine is turning.
To Stop: turn Engine Control switch to Off
position.
Engine Indicator Lights
4
Battery Charging Light (If Equipped)
Light goes on if engine alternator is not charg-
ing battery. Engine continues to run.
Y Stop engine and fix trouble if Battery
Charging light goes on.
5 Engine Temperature Light
Light goes on and engine stops if engine tem-
perature is above 221 ° F (105 ° C).
Y Stop engine and fix trouble if Engine
Temperature light goes on.
6 Engine Oil Pressure Light
Light goes on and engine stops if oil pressure
is below 10 psi (69 kPa). Light goes on mo-
mentarily during start-up but goes out when
engine reaches normal oil pressure.
Y Stop engine and fix trouble if Engine
Oil Pressure light stays on after start-
up.
7 Fuel Light
Light goes on and engine stops if fuel level is
low. Add fuel to resume operation.
8
Engine Hour Meter
Engine Gauges
.
To read gauges and engine indicator
lights with engine off, turn Engine Control
switch to Run/Idle and press Magnetic
Shutdown switch (see Section 7-8).
9 Fuel Gauge
10 Battery Voltmeter (Optional)
Use gauge to check battery voltage and moni-
tor the engine charging system. The meter
should read about 14 volts dc when the en-
gine is running, and about 12 volts dc when
the engine is stopped.
11 Engine Coolant Temperature Gauge
(Optional)
Normal temperature is 180 - 203 ° F (82 - 95 °
C). Stop engine if temperature exceeds 221 °
F (105 ° C).
12 Engine Oil Pressure Gauge (Optional)
Normal pressure is 30 − 60 psi (207 − 414
kPa). Stop engine if pressure is below 10 psi
(69 kPa).
Weld Controls
.
Max OCV Control Circuit: This unit has
a max OCV control circuit that resets Am-
perage Adjust control R1 to maximum
when the arc breaks. When an arc is
struck, weld output control returns to the
R1 front panel or combination front panel/
remote control setting. The Amperage
Adjust control adjusts amperage only
when welding and does not adjust open-
circuit voltage.
The max OCV circuit is disabled when
the Stick/TIG Selection switch is in
Scratch Start TIG position (see item 15).
13 Ampere Range Switch
Y Do not switch under load.
Use switch to select weld amperage range.
For most welding applications, use lowest
amperage range possible to help prevent arc
outages.
14 Amperage Adjust Control
Control adjusts amperage within range se-
lected by Ampere Range switch. Weld output
would be about 223 A DC with controls set as
shown (50% of 125 to 320 A).
15 Stick/TIG Selection Switch
Use switch to disable max OCV circuit for
scratch start TIG welding (see max OCV note
under Weld Controls). When switch is in Stick
position, the max OCV circuit resets Amper-
age Adjust Control R1 to maximum when the
arc breaks. When switch is in Scratch Start
TIG position, max OCV circuit is disabled and
OCV changes when the control is adjusted.
.
If Stick/TIG Selection switch is in TIG
position, turn Amperage Adjust control to
max for full output from optional auxiliary
power plant.
16 Amperage Adjust Switch And Remote
Amperage Adjust Receptacle
Connect optional remote control to RC13
(See Section 4-10). Use switch to select front
panel or remote amperage control. For re-
mote control, place switch in Remote position
and connect remote control to Remote Am-
perage Adjust receptacle RC13 (see Sec-
tions 4-10 and 5-3).
17 Polarity Switch (Optional)
Y Do not switch under load.
Use switch to change weld output. Select ei-
ther DC Electrode Positive (DCEP) or DC
Electrode Negative (DCEN).
Weld Meters
18 DC Voltmeter (Optional)
Voltmeter displays voltage at the weld output
terminals, but not necessarily the welding arc
due to resistance of cable and connections.
19 DC Ammeter (Optional)
Ammeter displays amperage output of the
unit.