Lincoln Electric PM 255 Product Description, Recommended Processes and Equipment, Limitations

B-2 OPERATION B-2

PRODUCT DESCRIPTION

The PM 255 is a complete semiautomatic constant voltage DC arc welding machine built to meet NEMA specifications. It combines a constant voltage power source and a constant speed wire feeder with a micro- computer-based controller to form a reliable high-per- formance welding system. A simple control scheme, consisting of continuous full range voltage and wire feed speed controls, provides versatility with ease of use and accuracy.

Other features include a 2" (51 mm) O.D. wire reel spindle with adjustable brake, an integral gas cylinder mounting undercarriage, an adjustable CO2 or Argon blend flow regulator with cylinder pressure gauge and inlet hose, a 12 ft. (3.6 m) Magnum 250L GMAW gun and cable with fixed (flush) nozzle, a 10 ft. (3.0 m) power cable with plug and mating receptacle, and a 10 ft. (3.0 m) work cable with clamp.

An Optional Timer kit provides variable burnback con- trol, a spot function, a selectable 4-step trigger inter- lock and adjustable “Run In” for wire starting optimiza- tion. Also optional are a Spool Gun Adapter kit, a Dual Cylinder Mounting kit and an Aluminum Feeding Kit for push feeding with standard built in feeder.

RECOMMENDED PROCESSES AND EQUIPMENT

The PM 255 is recommended for GMA welding processes using 10 to 44 lb (4.5 to 20 kg) 2" (51 mm) I.D. spools or Readi-Reel®coils (with optional adapter) of .025" through .045" (0.6 – 1.2 mm) solid steel, .035" (0.9 mm) stainless, 3/64" (1.2 mm) alu- minum and .045" (1.2 mm) Outershield®; as well as

.035" (0.9 mm) and .045" (1.2 mm) Innershield® self- shielding electrodes.

The PM 255 is factory equipped to feed .035" (0.9

mm)electrodes and provides tip, guide, and drive rolls for .045(1.2mm) electrode. It also includes a 200A, 60% duty cycle (or 250A, 40% duty cycle) rated, 12 ft. (3.6 m) GMAW gun and cable assembly equipped for these wire sizes. Use of GMAW processes requires a supply of shielding gas.

WELDING CAPABILITY

The PM 255 is rated at 250 amps @ 26 volts, at a 40% duty cycle based on a ten minute cycle time. It is capable of higher duty cycles at lower output currents and capable of up to 300 Amps at lower duty cycles.

LIMITATIONS

The PM 255 MAY NOT operate satisfactorily if pow- ered with a portable or in-plant generating system.

DESCRIPTION OF CONTROLS

Power ON/OFF Switch — Place the lever in the “ON” position to energize the PM 255. When the power is on, the red LED display lights illuminate.

Voltage Control — This is a continuous control that gives full range adjustment of power source output voltage. It can be adjusted while welding over its 10 to 28 volt range.

Wire Speed Control — This controls the wire feed speed from 50 – 700 inches per minute (1.2 – 17.8 m/min). The control can be preset on the dial to the setting specified on the Procedure Decal on the inside of the wire compartment door. Wire speed is not affected when changes are made in the voltage con- trol.

WIRE DRIVE ROLL

The drive rolls installed with the PM 255 each have two grooves, both for .030-.035" (0.8-0.9 mm) solid steel electrode. Drive roll size is indicated by the sten- cilling on the exposed side of the drive roll. If feeding problems occur, then the drive roll may be reversed or changed. See “Procedure for Changing Drive Roll” in this section. This information also appears on the Procedure Decal on the door inside the wire compart- ment. An additional drive roll set is provided for

.045"(1.2mm) solid steel electrode, packaged stan- dard with each machine.

WIRE SIZE CONVERSION PARTS

The PM 255 is rated to feed .025 through .045" (0.6- 1.2 mm) solid or cored electrode sizes.

The drive roll kits and Magnum 250L gun and cable parts are available to feed different sizes and types of electrodes. See Accessories section.

PM 255