Lincoln Electric LN-9F GMA, LN-9 GMA Circuit Protection and Automatic Shutdown, Circuit bREAKER

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OPERATION

CIRCUIT bREAKER AND GROUNDING LEAD PRO- TECTOR (GLP) RESET SWITCH: These protection circuit devices are located on the front rail of the LN-9 GMA model and bottom panel of the LN-9F models. See the topic "Circuit Protection and Automatic Shutdown" later in this section of the manual.

DIGITAL METER: A three-digit digital meter is provid- ed to set and monitor the welding procedure. The arc voltage is displayed in volts and the wire feed speed is displayed in inches/minute or meters/minute.

METER READING SWITCH, VOLTS AND WIRE SPEED CONTROLS: This four-position rotary switch is located to the right of the digital meter on LN-9 GMA models and to the left of the digital meter on LN-9F models. When set to the "Volts" position, the meter reads the arc voltage setting as adjusted by the "Volts" control. The rated setting range for all the LN-9 GMA models is 12.0 to 60.0 volts.

The three "Wire Speed" positions include an English position, for meter readings in inches/minute; and "LO" and "HI" range metric positions for meter readings in meters/minute. The wire feed speed setting is adjust- ed by the "Wire Speed" control. The rated setting range for all the LN-9 GMA models are 80 to 980 inch- es/minute (2.03 to 24.9 meters/minute).

When using metric meter readings, set the switch to "LO" for more precise meter readings up to 393 in/min (9.99 m/min.). For higher wire feed speeds, the "LO" position will result in an over-range meter reading of

E.EEwhich indicates that the "HI" range, with single decimal place resolution, should be used. Similarly, EEE will be displayed on the English position if the set- ting exceeds 999 inches/minute.

The procedure adjustments can be made before or during the weld. This feature permits the operator to set the welding voltage and wire speed before welding and without assistance.

Once set, the control circuits of the LN-9 GMA will con- tinuously monitor the volts and wire speed and correct any deviation from the set value so there will be negli- gible change.

Should the range of the power source output voltage be such that the unit circuit cannot keep the arc voltage as set, the unit will stop welding shortly after the arc is struck. See the topic "Circuit Protection and Automatic Shutdown" later in this section of the manual.

SET-ACTUAL PUSHbUTTON: After the weld has been started, the ACTUAL voltage or wire speed can be read by pressing the pushbutton to the left of the meter. The METER READING switch must be set in the desired position. When the pushbutton is not being operated, the meter continues to read the SET value.

CIRCUIT PROTECTION AND AUTOMATIC SHUTDOWN

CIRCUIT bREAKER

The circuit breaker normally trips only when excessive loading in the wire feed cable or a defective motor or control component causes an overload. After allowing a minute for cooling, push in the circuit breaker button and weld. If it trips again, be sure the wire feed cable is clean and the proper size for the wire diameter being fed. If the breaker still trips, look for a defective elec- trical component. When the circuit breaker is tripped, the digital meter is off and the trigger circuit will not operate.

POWER SUPPLY FUSE

The fuse on the PM power board inside the control box protects the power supply circuit. When the fuse is blown, the digital meter is off and the trigger circuit will not operate.

VOLTAGE PC bOARD FUSE

The 1/8 amp fast-blow fuse protects the LN-9 GMA cir- cuitry from damage that may result from a ground, or case, faulted control lead. If this fuse blows, the LN-9 GMA arc voltage sensing lead circuit will be opened. See the topic "Automatic Shutdown" below.

AVOIDING GROUNDING LEAD PROTECTOR (GLP) SHUTDOWN

The frames of all LN-9 GMA wire feed units and drive motors are grounded to the frame of the power source by a lead in the control cable. An overload protector prevents welding current from damaging this lead if the electrode circuit touches the wire feeder frame while the gun trigger is pressed.

LN-9 GMA and LN-9F GMA Wire Feeder