Theory Of Operation; General Description - Lincoln Electric Ranger 305D Service Manual

E-2
FIGURE E.2 – BATTERY, ENGINE, ENGINE PROTECTION, CHARGING, IDLE CONTROL
ENGINE
PROTECTION
LIGHT
ENGINE
PROTECTION
CIRCUIT
FUEL
PUMP
FUEL
SOLENIOD
HOLD COIL
PULL COIL
START
BUTTON
GLOW
PLUG
BUTTON
12V.
BATTERY
RUN
STOP
SWITCH

GENERAL DESCRIPTION

The Ranger 305D is a diesel engine-driven welding
power source capable of producing 300 amps at
29VDC at a 100% duty cycle. The engine is coupled to
a brush-type alternating current generator. This AC
output is rectified then controlled by Chopper
Technology to produce DC current for multi-purpose
welding applications. The Ranger 305D is also capa-
ble of producing 9,500 watts (10,000 watts peak) of AC
auxiliary power at 100% duty cycle.
Battery, Engine, Engine Protection,
and Charging System.
BATTERY:
The 12VDC battery powers the engine starter motor,
glow plug circuit, engine protection circuit, fuel pump
(codes 10926 and 11121), and fuel solenoid. Power is
also supplied to other components.
NOTE: Unshaded areas of Block Logic Diagram are the subject of discussion.

THEORY OF OPERATION

All manuals and user guides at all-guides.com
CHARGING
SYSTEM LIGHT
(CODE 10926 ONLY)
ENGINE
GLOW
ENGINE
SENSORS
PLUGS
ALTERNATOR
ENGINE
STARTER
IDLE
SOLENOID
PULL HOLD
COIL COIL
FLASHING
PULL COIL
PC BOARD
RANGER 305D
POWER
MODULE
WELD
WINDING
ROTOR
STATOR
ER 42 VAC
EXCIT 120/240 VAC
WINDING
AUX.WINDING WINDING
CURRENT
SENSOR
14
240
PIN
VAC 120 AMPHENALS
6
RECEPTACLES vac
PIN
Starting the engine:
Starting the engine first requires that the Run/Stop
switch be in the run position. The glow plug button is
then pressed and held; this preheats the engine to
enhance starting and also temporarily provides power
to the fuel pump (codes 10926 and 11121), and fuel
solenoid hold coil.
The start button is pressed while still holding the glow
plug button. The start button cranks the engine and
powers the fuel solenoid pull cord.
The engine starts, builds oil pressure, and spins the
engine alternator, which begins charging the battery.
The charging system indicator light (code 10926), and
the engine protection indicator will turn off. When the
engine protection light turns off, the fuel pump (codes
10926 and 11121), and fuel solenoid are receiving
power from the engine protection circuit. The operator
can now release the glow plug button.
The engine protection system now monitors the oil
pressure and coolant temperature sensors. If either
sensor detects a fault condition, the engine protection
indicator will light, and power will be interrupted to the
fuel solenoid, immediately shutting the engine off.
E-2
SHUNT
IGBTs
CHOKE
AMP
DISPLAY
WELD CONTROL
VOLT
P.C. BOARD
DISPLAY
IDLE
SWITCH
OUTPUT
MODE WELDING
CONTROL
SWITCH TERMINAL
SWITCH
ARC
CONTROL
+
-