Lincoln Electric K2820-1 Operating instructions

Brand: Lincoln Electric

Model: K2820-1

Category: Welding System

Type: Operating instructions

B-1

OPERATION

PLASMA 20

B-1

SAFETY PRECAUTIONS

DESCRIPTION

The PLASMA 20 is a constant current, continuous

control plasma cutter power source.

The PLASMA 20 comes standard with an air regulator

and pressure gauge. The unit is powered from a

115Vac, 20 amp input circuit with a 40% duty cycle

rating on a 10 minute basis, with 20 amp output. The

unit includes a hand-held torch with consumables and

a work cable with clamp.

The PLASMA 20 utilizes a 3 second delay after press-

ing the trigger before arc initiation to ensure that the

operator is ready. The unit will not function if consum-

ables are not installed correctly or missing, protecting

the user. The unit uses pneumatic-action for arc initi-

ation and does not use high-frequency.

Plasma is a gas that is heated to an extremely high

temperature and ionized so that is becomes a conduc-

tor of electricity.

This cutting procedure utilizes the plasma to transfer

the electric arc to the metal workpiece. The arc melts

a small amount of the work piece and the compressed

air blows away the molten metal there by producing

the cutting action.

The torch uses compressed air from a single source,

for both the plasma, cooling and protective gas.

The start of the cycle is determined by an arc, called

the pilot arc, which is struck between the moveable

electrode (negative polarity) and the torch nozzle

(positive polarity) due to a short circuit between these

two elements.

When the torch is brought near the workpiece to be

cut and the trigger is pressed the pilot arc is trans-

ferred between the electrode and the workpiece thus

striking a plasma arc, also called the cutting arc.

The duration of the pilot arc is set in the factory at 3

seconds; if the transfer has not been made within this

time, the cycle is automatically stopped except for the

cooling air which is kept on.

ELECTRIC SHOCK

can kill.

• Do not touch electrically live parts

or electrode with skin or wet

clothing.

• Insulate yourself from work and

ground.

• Always wear dry insulating

gloves.

FUMES AND GASES

can be dangerous.

• Keep your head out of fumes.

• Use ventilation or exhaust to

remove fumes from breathing

zone.

WELDING, CUTTING and

GOUGING SPARKS

can cause fire or explosion

• Keep flammable material away.

• Do not weld, cut or gouge on contain-

ers that have held combustibles.

Observe additional Safety Guidelines detailed in

the beginning of this manual.

WARNING

ARC RAYS

can burn.

• Wear eye, ear and body

protection.

PLASMA ARC

can injure

• Keep your body away from nozzle

and plasma arc.

• Operate the pilot arc with caution. The

pilot arc is capable of burning the

operator, others or even piercing

safety clothing.

B-2

OPERATION

B-2

PLASMA 20

CONTROLS AND SETTINGS

1. ON/OFF Switch – In the ON position the machine

is ready for normal operation. All system control

circuits are activated. OFF position deactivates

control circuits.

2. Output Current Knob-Adjusts the cutting current

supplied by the machine according to the thick-

ness of material/speed.

3. Green LED – Turns ON when input voltage is

applied within normal range – blinks slowly when

input voltage goes above 130Vac, or below

95Vac.

4. Red LED – Turns ON when torch is triggered

Blinks quickly during 3 second safety pre-flow

prior to pilot arc ignition Blinks slowly if cutting arc

is not initiated after 3 second pilot arc ignition.

5. Yellow LED – Turns ON when the thermal protec-

tion is activated. Blinks slowly when the under

pressure protection is working (the pressure is

under 55 PSI, 3.8 Bar)

6. Air Regulator – Adjusts the input air pressure –

pull upward to unlock, press down to lock – nomi-

nal air pressure setting is 65 PSI, 4.5 Bar.

Note: Regulator should never be set above 87 PSI (6

Bar).

7. Compressed Air Connection

8. Input Cord

9. Work cable with clamp

10. Torch

USER RESPONSIBILITY

Variation such as plate chemistry, plate surface condi-

tion (oil, scale), plate thickness, preheat, quench,

gas type, gas flow rate and equipment may produce

results different than those expected. Some adjust-

ments to procedures may be necessary to compen-

sate for unique individual conditions. Test all proce-

dures duplicating actual field conditions.

DESIGN FEATURES AND

ADVANTAGES

• Light weight

• Continuous output control

• Indicator LEDs

• Cooling fan

• Rapid arc restrike for cutting across gaps

• 3 second arc delay for safety

•

Adjustable air pressure regulator with locking feature

•

Part-in-place verification for safety and proper operation

• Thermostatic protection with thermal indication

• Air inlet filter with water purge button to protect air

path and torch

• Lighted ON/OFF switch

• High input voltage protection

CUTTING CAPABILITY

The PLASMA 20 is rated for 20A @ 40% duty cycle.

The unit is designed to cut up to 3/8” inch mild steel,

but has the capability to cut other metals such as

stainless and aluminum (travel speed will vary).

TORCH CONSUMABLES

The torch consumables consist of an Electrode, Gas

Distributor Ring, Nozzle, and Shield Cup. The con-

sumable parts must be placed in the correct order and

secured properly for the unit to operate.

LIMITATIONS

• For indoor use only.

• Do not exceed output current and duty cycle rating

of machine. Do not use the PLASMA 20 for pipe

thawing.

• Do not power with generators or engine drives.

B-3

OPERATION

B-3

CHECKING AIR QUALITY

To check air quality, deactivate the torch (post-flow)

and place a welding filter lens in front of the torch. Any

oil or moisture in the air will be visible on the lens. DO

NOT initiate pilot arc while checking air quality.

When preparing to cut, position the machine as close

to the work as possible. Make sure you have all

materials needed to complete the job and have taken

all safety precautions. It is important to follow these

operating steps each time you use the machine.

• COMPRESSED AIR

The PLASMA 20 requires compressed air to be

attached to the unit. The input air pressure mini-

mum must be 72.5 PSI, 5 Bar and must not exceed

150 PSI, 10.3 Bar. An air regulator is included with

the unit with optimum pressure setting set to 65

PSI, 4.5 Bar.

The unit is also equipped with an air filter which cap-

tures water and oil vapor. The vapor collected can

be drained out of the bottom of the unit by turning

the drain button. The unit will not operate if the

input air pressure is below 55 PSI, 3.8 Bar.

Three Position Drain knob: (See Figure B.1)

1. Open

2. Open when no air pressure, closed when air pres-

sure.

3. Closed

CUTTING WITH A HAND TORCH

• Turn the main power and the machine power switch

on.

- The fan should start.

- The pre-charge circuit will operate for 3 seconds,

then the green "Power" LED should turn on.

• Be sure that the work lead is clamped to the work-

piece before cutting.

• Set the output current control knob at maximum

position for higher cutting speed and less dross for-

mation. Reduce the current, if desired to reduce the

kerf (cut) width, heat affected zone or travel speed

as required.

PLASMA 20

CUTTING OPERATIONS

BEFORE CUTTING

ELECTRIC SHOCK CAN KILL.

Disconnect input power by removing

the plug from the receptacle before

assembling or disassembling torch

parts, or torch and lead assemblies.

------------------------------------------------------------------------

Check and follow instructions listed in the “Safety and

Installation” section of this manual.

TORCH PARTS

Check the torch for proper assembly. Install proper

torch parts for the desired application (refer to the

Torch Consumable Parts Selection Section).

NOTE: The power supply will not operate unless the

torch shield cup is fully seated against the PIP

(Parts in Place) pins in the torch head.

INPUT POWER

Check the power source for proper input voltage.

Make sure the power source meets circuit protection

and wiring requirements.

Plug in power cord to supply input power to the unit.

GROUND CABLE

Check for a solid ground cable connection to the

workpiece.

AUTOMATIC PURGE SYSTEM

Place the ON/OFF switch to the ON position. If the

line voltage is OK, the green LED will turn on. Activate

the torch trigger to initiate air purge. There will be a 3

second delay to remove any condensation that may

have accumulated in the torch and air lines while the

system was shut down. When the air purge (Air safety

time) is complete, pilot arc will be initiated.

FIGURE B.1

WARNING

KNOB

B-4

OPERATION

B-4

NOTE: For better torch control, it is acceptable to let

the nozzle drag along the work piece surface. This

will shorten nozzle life. Also, it is acceptable to place

a non-conductive torch guide on the work piece in

order to achieve a cleaner cut

• When the trigger is released, the arc will stop.

- The gas will continue to flow for 20 seconds of

postflow. If the trigger is activated within this time

period, the pilot arc will restart after the 3 second

delay.

• If the dross is difficult to remove, reduce the cutting

speed. High speed dross is more difficult to remove

than low speed dross.

• The right side of the cut is more square than the left

as viewed along the direction of travel.

• Clean spatter and scale from the nozzle frequently.

Parts in place:

• Check the assembly of the torch consumables. If

they are not properly in place, the machine will not

start. Make sure that the shield cup is hand

tight. Do not use pliers or over tighten.

• Check the conditions of the inside of the nozzle. If

debris has collected, rub the electrode on the inside

bottom of the nozzle to remove any oxide layer that

may have built up. Refer to the “Routine

Maintenance Section".

• Check the condition of the electrode. If the end has

a crater-like appearance, replace it along with the

nozzle. The maximum wear depth of the electrode

is approximately .062”. A green and erratic arc will

indicate definite electrode failure and the electrode

should be replaced immediately.

• Replace the nozzle when the orifice exit is eroded

away or oval shaped.

ELECTRIC SHOCK CAN KILL.

Disconnect input power by removing

the plug from the receptacle before

assembling or disassembling torch

parts, or torch and lead assemblies.

------------------------------------------------------------------------

• If the machine does not reset or continues to trip,

consult the Troubleshooting Section.

• Use the proper cutting procedures referred to in

Procedure Recommendations.

PLASMA 20

• When ready to cut, place the torch near the work,

make certain all safety precautions have been taken

and pull the trigger.

- The air will flow for a preflow time of 3 seconds

and the pilot arc will start.

- The pilot arc will run for 3.0 seconds and shut off

unless the arc is brought in contact with the work

and the arc is transferred. Avoid excessive pilot

arc time by transferring the arc to the workpiece

quickly.

- When the arc is brought within 1/8” - 1/4" from

the work piece: the arc will transfer, the current

will ramp to the setting on the control panel, and

the cut can last indefinitely (or until the duty cycle

of the unit is exceeded).

• Pierce the work piece by slowly lowering the torch

onto the metal at a 30

angle away from the opera-

tor. This will blow the dross away from the torch noz-

zle. Slowly rotate the torch to vertical position as the

arc becomes deeper.

NOTE: Graphics shown are for understanding torch

angles for best results – the distances from the work

piece are exaggerated. In actual operation, the noz-

zle should be held just above the work piece surface.

• Keep moving while cutting. Cut at a steady speed

without pausing. Maintain the cutting speed so that

the arc lag is 10° to 20° behind the travel direction.

•

Use a 5° - 15° leading angle in the direction of the cut.

• Finish the cut to be made and release the trigger.

3030

VERVERTICAL ANGLETICAL ANGLE

FOR CUTTINGFOR CUTTING

CUT

TORCH AT 30

ANGLE

TO PIERCE

ROTATE TO

ANGLE TO CUT

Direction of Travel

5° - 15°

10° - 20°

Arc Lag

Leading Angle

WARNING

B-5

OPERATION

B-5

OPERATING FAULTS

During cutting operations performance faults may

arise, such as:

• Insufficient penetration:

too high cutting speed;

torch is tilted;

piece is too thick;

cutting current is too low;

torch parts are worn out;

non-genuine Manufacturer’s parts.

• Interruption of the cutting arc:

cutting speed too slow;

excessive distance between torch and work

piece;

Input Voltage too low-reduce output current;

torch parts are worn out;

non-genuine Manufacturer’s parts;

poor work cable connection/disconnected.

• Excessive slag/dross:

too low cutting speed (bottom dross);

too high cutting speed (top dross);

excessive distance between torch and work

piece;

cutting current too low;

torch parts are worn out;

non-genuine Manufacturer’s parts.

• Tilted cutting (not perpendicular):

torch position not correct;

asymmetric wear of nozzle hole and/or

incorrect assembly of the torch parts.

• Excessive wear of nozzle and electrodes:

air pressure too low;

exceeding system capability (material too

thick);

contaminated air (humidity/oil);

excessive pilot arc ignitions in the air;

improperly assembled torch;

torch nozzle contacting workpiece;

damaged or loose torch head components;

non-genuine Manufacturer’s parts.

PLASMA 20

PILOT ARC DISCUSSION

The PLASMA 20 has a smooth, continuous pilot arc. The

pilot arc is only a means of transferring the arc to the work-

piece for cutting. Repeated pilot arc starts, in rapid succes-

sion, is not recommended as these starts will generally

reduce consumable life. Occasionally, the pilot arc may

sputter or start intermittently. This is aggravated when the

consumables are worn or the air pressure is too high.

Always keep in mind that the pilot arc is designed to transfer

the arc to the workpiece and not for numerous starts without

cutting.

When the pilot arc is started, a slight impulse will be felt in

the torch handle. This occurrence is normal and is the

mechanism which starts the plasma arc. This impulse can

also be used to help troubleshoot a "no start" condition.

HEILD CUP

NOZZLE

ELECTRODE

ORCH HEAD

SSEMBLY

GAS DIFFUSER RING

FIGURE B.2

ELECTRIC SHOCK CAN KILL.

Disconnect input power by removing

the plug from the receptacle before

assembling or disassembling torch

parts, or torch and lead assemblies.

--------------------------------------------------------------------------------

WARNING

Be sure the operator is equipped with proper gloves,

clothing, eye and ear protection. Make sure no part of

the operator’s body comes in contact with the work

piece while the torch is activated.

Sparks from the cutting process can cause dam-

age to coated, painted, and other surfaces such as

glass, plastic and metal.

NOTE: Handle torch cable with care and protect

it from damage.

------------------------------------------------------------------------

TORCH CONSUMABLE PARTS

SELECTION

To change the torch consumable parts use the follow-

ing procedure:

NOTE: The nozzle, gas distributor, and electrode are

held in place by the shield cup. Position the torch with

the shield cup facing upward

to prevent these parts

from falling out when the cup is removed.

1. Unscrew and remove the shield cup from the Torch

Head Assembly. Figure B.2 Consumable Parts.

2. Remove the nozzle, gas distributor, and electrode.

3. Install the electrode, gas distributor and nozzle.

4. Hand tighten the shield cup until it is seated on the

torch head. If resistance is felt when installing the

cup, check the threads before proceeding.

CAUTION

Lincoln Electric K2820-1 Operating instructions

Brand: Lincoln Electric

Model: K2820-1

Category: Welding System

Type: Operating instructions

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Lincoln Electric K2820-1 Operating instructions

Lincoln Electric K2820-1 Operating instructions

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