HUAYUAN LGK-200MA User manual

LGK-200/300/400MA
AIR PLASMA CUTTING MACHINE
MANUAL
INSTRUCTION
(PLEASE READ IT CAREFULLY BEFORE OPERATION)

Safety Depends on You
HUAYUAN arc welding and cutting equipment are designed and built with ample safety consideration. However, proper
installing and operating can ensure your safety.
DO NOT INSTALL, OPERATE OR REPAIR THIS EQUIPMENT CASUALLY WITHOUT READING THIS MANUAL THROUGHOUT.
Special Notes (Very Important):
1. Pay attention to avoiding the machine falling down when it is placed on the gradient ground.
2. It is forbidden to unfreeze the pipeline by the cutter.
3. The shield rank of this series of cutter is IP21S, so working in rain is not suitable.
4．The cutter has external static characteristic with rated duty cycle 100%, which means the machine can work continuously
at the rated cutting current. The machine has the function of thermal protection. When the internal temperature exceeds a
set temperature, thermal protection moves on and the abnormal indicator lamp on the panel turns ON, then there is no
output in cutter. The machine can become normal and work only after the internal temperature drops down and the
abnormal indicator lamp on the panel turns OFF.
Purchase Date：_______________
Serial Number：_______________
Machine Model：______________
Purchase Place：______________

Cautions
Arc and arc rays can hurt.
All performing welding workers ought to have health qualification from the authority organization to prevent you and
others from arc radiation and burn. It should be prevented for children to enter into dangerous area as well.
Be careful reading the following important items and the welder safety bye from the authority organization. Be sure that
qualified professionals perform all installation, maintenance and repair procedures.
1 Electric shock: The welding circuits are not insulated when welding. If you touch the two output
electrodes of the machine with your bare skin at the same time, it will lead to electric shock, sometimes
even fatal dangers. Users need to follow the items below to avoid electric shocks:
If possible, lay some insulating materials, which are dry and large enough, in your working field. Otherwise,
use the automatic or semiautomatic welding machine, DC welding machine as possible as you can.
Components in the automatic and semiautomatic welding machine such as the welding wire reel, feed wheel,
contact tip and welding head are all electric components. .
Always be sure the machine has been connected perfectly to the work piece with the work cables and should
be as close as possible to the working area.
The work piece should be grounded perfectly.
Make sure that the insulating material of the electrode holder, the grounding clamp, the welding cable and
the welding head are not affected by damp, mildewed or spoilt, and be replaced momentarily.
Never dip the electrode in water for cooling.
Never touch electric components of two welding machines at the same time, because this voltage is
supposed to be two times of welding voltage while the grounding mode is not clear.
While working high above the ground or other places having the risk of falling, please be sure to wear safety
belt to avoid losing balance caused by electric shock.
2 Arc: Use an arc welding mask to protect your eyes and skin from sparks and the rays of the arc, pay
special attention to the filter glass, which must be conformable to the national standard.
Use clothing made from durable flame-resistant material or sailcloth to protect your skin
from hurting by the arc rays.
Remind other nearby personnel before working lest arc rays hurt them by accident.
3 Fumes and Gases: Welding may produce fumes and gases hazardous to health. Avoid breathing these
fumes and gases. While working in limited room, use enough ventilation and/or exhaust to keep fumes
and gases away from the breathing zone, or use the respirator. Do not weld at the same time when
using of degreasing, cleaning or spraying operations. The heat and rays of the arc can react with these gases to form
phosgene, a highly toxic gas,
Some protective gases used in welding might displace the oxygen in the air, and can lead to hurt or even
death.
Read and understand the manufacturer’s instructions for this equipment, and validate the health certification
of consumptive materials, make sure they are innocuous.
4 Spatter: Spatter can cause fire or explosion.
Remove fire hazards from the welding area. Remember that spatter from welding can easily
go through small cracks and touch fire hazards. Protect all kinds of lines going though welding
area, including hydraulic lines in the wild.

Where compressed gases are to be used in the field, special precautions should be used to prevent explosion.
When welding stops, make certain that no live part is touching the work piece or the work stage. Accidental
contact can create a fire hazard.
Do not weld containers or lines, which are not proved to be innocuous.
It is very dangerous to heat, cut or weld tanks or containers at entry holes. Does not start work until the
proper steps have been taken to insure that there is no flammable or toxic gas.
Spatter might cause burn. Wear leather gloves, heavy shirt, trousers, high shoes and a cap over your hair to
prevent from burning by spatter. Wear the ear shield when performing sideways or face up welding. Always wear
safety glasses with side shields when being in a welding area.
The welding cables should be as close to the welding area as possible, and the short, the better. Avoid
welding cables going through the building framework, lifting chains, AC or DC cables of other welding machines and
appliances. The welding current is strong enough to damage them while having short circuit with them.
5 Cylinder: Damage of it might cause explosion.
Make sure that the gas in the storage cylinder is qualified for welding, and the
decompression flow-meter, the adapter and the pipe are all in good condition.
Make sure that the installation of cylinder is by the wall and bundled tightly by a chain.
Be sure to put the cylinder in the working space with no crash or shake, and far from welding area.
It is forbidden to touch cylinder with the welding clamp or the work cables.
Avoid facing the cylinder while installing the decompression flow-meter or the gasometer.
When not working, please tighten the valve.
6 Power: (For electrically powered welding and cutting equipment) Turn off input power before
installation, maintenance and repair, so that avoid accident.
HUAYUAN welding equipment is Ι class safeguard equipment; please install the equipment
in accordance with the manufacturer’s recommendations by specific persons.
Ground the equipment perfectly in accordance with the manufacturer’s recommendations.
7 Power:(For engine driven welding and cutting equipment)
Work in ventilated place or outdoors.
Do not add fuel near to fire or during engine starting or welding. When not working, add fuel
after engine is cooling down; otherwise, the evaporation of hot fuel would result in dangers. Do not
splash fuel out of the fuel tank, and do not start the engine until complete evaporation of the
outside fuel.
Make sure that all the safeguard equipment, machine cover and devices are all in a good
condition. Be sure that arms, clothes and all the tools do not touch all the moving and rotating
components including V belt, gear and fan etc.
Sometimes having to dismantle some parts of the device during maintenance, but must keep safety
awareness strongly every time.
Do not put your hand close to fans and do not move the brake handle while operating.
Please remove the connection between the engine and the welding equipment to avoid sudden starting
during maintenance.
When engine is hot, it is forbidden to open the airtight cover of the radiator water tank to avoid hurt by the
hot vapor.
8 Electromagnetic: Welding current going though any area can generate electromagnetic, as well as the
welding equipment itself.
Electromagnetic would affect cardiac pacemaker, the cardiac pacemaker users should consult
one’s doctor first.

The effect of electromagnetic to one’s health is not confirmed, so it might have some negative effect to one’s
health.
Welders may use following method to reduce the hazardous of electromagnetic:
a. Bundle the cable connected to the work piece and the welding cable together.
b. Do not enwind partially or entirely your body with the cable.
c. Do not place yourself between the welding cable and the ground (work piece) cable, if the welding cable is by your
left side, then the ground cable should be by your left side too.
d. The Welding cable and the ground cable are as short as possible.
e. Do not work near to the welding power source.
9 Lift Equipment: carton or wooden boxes package the welding machines supplied by HUAYUAN. There
is no lifting equipment in its wrapper. Users can move it to the prospective area by a fork-lift truck, and
then open the box.
If having rings, the machine can be transited using rings. While HUAYUAN Welding Machine
Manufacture reminds users, there is possible risk to damage the welding machine. It is better to
push the welding machine moving in use of its rollers unless special situations.
Be sure that the appurtenances are all removed off when lifting.
When lifting, make sure that there is no person below the welding machine, and remind
people passing by at any moment.
Do not move the hoist too fast.

10 Noise: HUAYUAN Welding Machine Manufacture reminds users: Noise beyond the limit (over 80
db) can cause injury to vision, heart and audition depending on oneself. Please consult local medical
institution. Use the equipment with doctor’s permission would help to keeping healthy.

Content
1 SUMMARY ....................................................................................................................... 1
1.1 MODEL DESCRIPTION ............................................................................................................. 1
1.2 FEATURES ............................................................................................................................. 1
1.3 USAGE ................................................................................................................................. 1
1.4 SYMBOL INSTRUCTION ............................................................................................................ 1
2 SAFETY AND ATTENTION .................................................................................................. 2
3 WORKING ENVIRONMENT REQUIREMENTS ..................................................................... 3
4 TECHNICAL PARAMETERS .................................................................................................4
4.1 MAIN TECHNICAL PARAMETERS ................................................................................................4
4.2 PLASMA GAS CONDITION .........................................................................................................4
4.3 EXTERNAL CHARACTERISTIC CURVE ............................................................................................ 5
4.4 TORCH COOLANT REQUIREMENTS ..............................................................................................5
5 BASIC PRINCIPLE .............................................................................................................. 5
6 INSTALLATION AND OPERATION ....................................................................................... 6
6.1 MOVING AND LIFTING .............................................................................................................6
6.2 OPEN THE PACKING AND CHECK ................................................................................................6
6.3 THE FIX AND INSTALLATION OF THE POWER SOURCE ......................................................................6
6.4 THE CONNECTION OF 3PHASE INPUT POWER CABLE .....................................................................7
6.5 THE CONNECTION OF COMPRESSED AIR AND THE OPERATION OF PRESSURE REGULATING FILTER ............8
6.6 THE CONNECTION OF OUTPUT TERMINAL ....................................................................................8
6.7 PANEL FUNCTION INSTRUCTION .............................................................................................. 10
6.8 PROTECTION FUNCTION INTRODUCTION ................................................................................... 13
6.9 OPERATION .........................................................................................................................14
7 OPERATION AND SETTING ..............................................................................................16
7.1 POWER ON SELF TEST ............................................................................................................16
7.2 THE AIR PRESSURE ADJUST AND DISPLAY ...................................................................................16
7.3 LIQUID FLOW DISPLAY ........................................................................................................... 16
7.4 CUTTING CURRENT SETTING ...................................................................................................17
7.5 SECONDARY MENU ............................................................................................................... 17
7.6 TORCH MONITORING FUNCTION ..............................................................................................18
8 BRIEF INTRODUCTION OF THE CUTTING TECHNOLOGY ...................................................19
8.1 MAIN CUTTING PARAMETER AND THE TECHNICAL BASIS .............................................................. 19
8.2 CUTTING BURR ELIMINATING ISSUE ..........................................................................................20

8.3 CUTTING TABLE ....................................................................................................................22
9 PACKING LIST ................................................................................................................. 25
9.1 PACKING LIST OF PLASMA POWER SOURCE ................................................................................ 25
9.2 SYSTEM PACKING LIST ............................................................................................................25
10 MAINTENANCE .............................................................................................................25
11 TROUBLESHOOTING ..................................................................................................... 26
11.1 PLEASE FIRSTLY CHECK FOLLOWING ITEMS IF ANY TROUBLES ....................................................... 26
11.2 ORDINARY TROUBLESHOOTING AS FOLLOWING SHEET ............................................................... 27
11.3 MAIN COMPONENTS LIST .....................................................................................................28
12 APPENDIX：CIRCUIT DIAGRAM ....................................................................................37

1
1Summary
1.1 Model Description
L G K - □□□ MA
Series code
Rated cutting current
Air medium
Cutting
Plasma arc cutting machine
1.2 Features
LGK-200、300、400MA series plasma cutting machine have below features：
Adopt gas pressure sensor, the cutting torch can be properly protected when the gas
pressure is too low;
Adopt liquid flow sensor, the cutting torch can be properly protected when the
liquid flow is too low, and the liquid flow is displayed on the display meter;
The gas pre-flow time, gas post-flow time, current up-slope time can be separately
set according to the torch cable length;
The plasma gas pressure can be adjusted on the panel, the pressure is displayed on
the meter, friendly operation;
There is digital communication connector, can be connected with different
automation equipment;
With torch monitoring function, warning to change the consumables, to longer the
torch working life;
Intelligent fan is used to reduce the dust;
With automatic protection for over-heating , lack-voltage, lack coolant flow, etc
Integrated with torch coolant system,special for big power water cooling torch use
Suitable for mesh material cutting
1.3 Usage
It is suitable for cutting kinds of metal materials like low carbon steel, alloy steel and
non-ferrous metal and is widely applied in the manufacturing of boiler pressure
container, chemical container, industrial power station construction, metallurgy,
aerospace industry, automobiles, building an so on.
1.4 Symbol Instruction

2
Read the manual carefully
Dangerous voltage
Over-heat
Input voltage
Power abnormal
Output current
Air pressure
Voltage output
Coolant liquid input
Voltage input
Coolant liquid output
Cutting
Plasma torch
Check gas
Lock
Ground lead
Unlock
Protection ground lead
Water cooling
Remote control
Air cooling
Increase/ Decrease
The nozzle connection of
plasma torch
Plasma gas and torch
electrode
Current
Coolant liquid and torch
electrode
2Safety and attention
Please follow the notes for the safety of you and others.
It is forbidden to unfreeze the pipe line by cutting power or other usages except
for cutting.
The cutter casing should ground reliably. Please make sure the grounding bolts
of power ground reliably in case of electric shock.
Cutter is the equipment with high voltage. Please wear insulated protective
shield when cutting.
When exchanging torch and wearing parts, please turn off the supply power

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first.
Protective shield should be worn.
In order to avoid any hurt to eyes from ultraviolet radiation and strong light and
to skin from spatter, please wear protective shield according to related rules and
regulations of labor protection.
It is forbidden to inhale harmful gases.
The fumes and gases produced during cutting is hazardous to health. Please
wear protective shields and install aerator according to related rules and
regulations of labor protection.
Cutting cannot proceed in closed container.
The work-piece just after being cut is at high temperature. Please prevent from
scald.
Protective gas cylinder and air compressor must be placed in a fixed position
and prevented from collision.
Cutter and cutting place should be far away from flammable materials.
Prevent foreign bodies from entering inside the machine. And protect the cable
from sharp materials.
Protect the machine from fall or collision.
In case of fall or collision, it can be used only after professional checking.
In the surface or inside of the cutting work-piece, there should be no flammable
and explosive materials or chemical materials harmful to human.
Installation and repair person must have state-authorized electrician operation
certificate.
Cutting operation person should read this manual carefully and know the
operation method well.
3Working Environment Requirements
If not reach the flowing conditions, the cutting capacity may not reach
the technical specification values
1) Please use the machine in a clear place without any of dust, corrosive gas and
inflammable and explosives; Do not use it in open air and rain;
2) Required air relative humidity should ≤90％(at 20℃)，40℃≤50％(at 40℃)；
3) Environment temperature range should be at-10℃～40℃;
4) The coolant liquid cannot be frozen when use;
5) Any metal materials cannot be put on or insider the power source;
6) Keep the machine away from the wall of some other closure things at least 30cm,
two machines distance at least 30cm.
7) Use it under altitude lower than 1000m.

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4Technical Parameters
4.1 Main Technical Parameters
LGK-200MA
LGK-300MA
LGK-400MA
Rated input voltage
3～380/415V 50/60Hz
Rated input power
44.1 kVA
56.6 kVA
84.9 kVA
Rated input current
67A
86A
129A
Rated output current
200 A
300A
400 A
Rated output voltage
160 V
160 V
170 V
Rated duty cycle
60%
60%
60%
Open circuit voltage
370 VDC
Current adjust range
40～200 A
60～300 A
60～400 A
Quality cutting thickness（C.C）
(speed 200mm/min)
50 mm
60 mm
70 mm
Max cutting thickness（C.C）
70 mm
100 mm
120 mm
Plasma gas
Compressed air
Plasma gas pressure
0.4～0.6 MPa
Torch cooling mode
Air cooling/water cooling
Arc pilot mode
Non-contact
Insulation grade
F
Protection grade
IP21S
Dimension mm(L×W×H)
1040×415×1010
1130×480×1050
Weight
115 kg
150kg
4.2 Plasma gas condition
Gas pressure range：0.5MPa～0.7MPa
Gas supply pipe compression strength：≥1MPa
Gas supply pipe inner dimension：≥Φ8
Gas flow：≥180L/min
Filter the water in the gas, then feed into the plasma
Model
Parameter

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4.3 External characteristic curve
4.4 Torch coolant requirements
The coolant box is empty when delivery out. Before fulling the coolant box, please
check which coolant is suitable for your environment.
Warning! The cooling liquid is irritant to skin and eyes, if wrongly eat or
drink, it hurts even kills.
If skin and eyes contact with the coolant liquid, please wash immediately
with lot of clean water, then go to the hospital to ask for help.
Do not use the anti-freezing solution as the coolant, it hurt the torch! To
protect the bump and torch cooling system, please do use the special coolant
liquid.
The working temperature of the coolant liquid of this system is -12℃~40℃
If working temperature is not in the range of -12℃~40℃, please check the
suggestion of self-control mixed coolant liquid below. To make the self-control mixed
coolant liquid, please do use pure water in case of hurting the cooling system.
5Basic Principle
The control circuit of this cutting machine adopts advanced electronic part IGBT as the main
inverter switch component. Three-phase AC power is converted to 20KHz high-frequency DC
current after being rectified by three phase rectifier. Then under the function of IGBT inverter
the DC current is inverted to AC high frequency current, which is inverted to DC current after
experiencing voltage reduction in high frequency transformer, current rectifying in fast
recovery diode. This DC current is filtered through reactor, and the output cutting current is
obtained. Control circuit can control output current by controlling driven pulse width. The
real time cutting current, which is obtained through current sensor connected to output
terminal in series, is used as negative feedback control signal. After comparing with current
adjusting signal, the negative control signal is sent to PWM adjusting integrated circuit, then
a controlled driving pulse is output to control IGBT. Thereby a constant output current can be

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maintained, and a steep dropping & constant current external characteristic is obtained.
Striking arc adopts high-frequency striking model. The main circuit refers to appendix figure,
and principle diagram of control circuit is shown as below figure：
6Installation and operation
6.1 Moving and lifting
Power source should be shut off before moving the cutter；
The cutter bottom should be kept downwards during transportation. It is forbidden
to have cutter placed transversely or upended；
When lifting, it must be lifted vertically；
During the long-distance transportation, it must prevent the cutter from raining and
moving back and forth inside box. Shock absorption foam should be placed around
cutter；
6.2 Open the packing and check
1) Check the machine and packing according to the packing list, of there is any damage,
please try to contact the supplier
6.3 The fix and installation of the power source

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LGK-200MA Dimension and installation size
LGK-300/400MA Dimension and installation size
6.4 The connection of 3 phase input power cable
Power supply condition
1) Voltage fluctuation≤±10％；
2) Frequency fluctuation≤±1％；
3) Unbalance rate of three phase voltage≤5％；
4) The power supply condition please check the chart below:
Model
The sectional area of
input copper cable
(mm2)
The sectional area
of ground cable
(mm2)
Fuse (A)
Contact capacity
(A)
LGK-200MA
≥10
≥10
125
125
LGK-300MA
≥16
≥16
160
150
LGK-400MA
≥25
≥16
200
250
The connection of power lead
Use eligible cables and sockets to connect it, and must be operated by a qualified

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electrician.
Connection of ground cable
Connect it to ground on marking of the machine body), the sectional area
must match the requirements in above form, to ground firmly. Ground connecting
method should follow state standard.
6.5 The connection of compressed air and the operation of pressure
regulating filter
The function of pressure regulating filter please check the below figure
Pic 7：Air filter regulator
1) The compressed gas should meet the requirement mentioned in point “4.2 Plasma
gas conditions”. Connect the gas pipe with the gas inlet of air filter on the rear panel
and hoop it tightly.
2) The air filter regulator should be checked periodically. If the water level reaches
two-thirds of filter glass, it must be drained, or the cutting incision quality will be
effected. The gas supply valve should be closed during water draining, and Gas
Checking function is selected in panel. When the indicated valve of gas pressure
meter is zero, water will drain out from drainage mouth automatically.
6.6 The connection of output terminal
The connection of the torch
1) Connectors instruction
The pilot arc: to connect the arc striking wire of the torch;
Control: Pin 1 and 2 is start control, to connect the control switch of the torch.
Pin 3 and 4 is water cooling/air cooling. When use air cooling torch, short
connect the pin 3 and 4, when use water cooling torch, don’t connect the pin 3
and 4;

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Air & Current output: the negative output connector of the machine is the
plasma gas output connector, the connector thread is M14×1.5;
Water & Current output: the negative output connector of the machine is the
cooling water output connector, to connect the water inlet of the water cooling
torch, the connector thread is M16×1.5;
Water Return & Current: the negative output connector of the machine is the
cooling water return connector, to connect the return water of the water
cooling torch, the connector thread is M16×1.5 ;
Pic 6 The connectors of torch
2) The connection of air cooling torch (Please refer to the Pic 6 as above)
Firstly connect the torch air inlet cable connector with the copper tip marked with
Air & Current output on the front bottom panel; then connect the torch pilot wire
to terminal marked with Pilot arc on the front panel; Finally, connect the torch
control connector to the terminal marked with Control on the front panel and
screw down the nut;
3) The Connection of water-cooling torch (Please refer to the Pic 6 as above)
Firstly connect the torch cable connector (cooling water return) with the copper tip
marked with Water Return & Current on the front panel. Connect the torch cable
connector (cooling water output) with the copper tip marked with Water & Current
output on the front panel. Connect the torch gas pipe nut with the copper tip
marked with Air & Current output. then connect the torch pilot wire to terminal
marked with Pilot arc on the front panel; Finally, connect the torch control
connector to the terminal marked with Control on the front panel and screw down
the nut;

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4) The requirements of control plug connection when customers use different torches
Use WS20J4TQ 4-pins plug;
Requirements on air cooling torch connection:
a) Connect the 1, 2 pin of 4- pins plug to switch control wire of cutting torch;
b) Short connect 3, 4 pin of 4-pins plug by gummed wire;
Requirements on water cooling torch:
a) Connect the 1, 2 pin of 4-pins plug to switch control wire of cutting torch;
b) The 3, 4 pin don`t connect any of wire;
5) Connection of cutting ground cable
Connect the cutting ground cable with the copper tip on the front panel with nuts. The
other end of the cutting ground cable is firmly connected to work-piece.
6.7 Panel function instruction
Pic 9：LGK-200/300/400MA panel
Note: The title number is corresponding to the number on the Pic 9, for example,
the “1）” is corresponding to “1”on Pic 9.
1) coolant filter
2) Cutting torch connection thread hole: To pass through the cutting torch cable;
3) Operation mode select

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Function one: choose the “torch unlock” and “torch lock” function. When it turns on “torch
lock”, the torch switch should be pressed in the process of cutting, and the cutting stops after
loosening the switch. When it turns on “torch unlock”, press the torch switch and loosen it,
the cutting starts to work, and the stops after pressing the switch again;
Function two: press this knob for 5s, come into the second menu, after setting the parameter,
press the knob for 5s, then finish the setting
4) AIR CHECKING function: press this knob the gas check indicator is on,the machine is
in air checking status, all the valve is on;
5) The gas pressure adjusting valve: to adjust the gas pressure, pull it out and contra
rotate to reduce the gas pressure, rotate it clockwise to increase the gas pressure;
6) AIR CHECKING indicator: when this indicator is on, mean it’s on air checking status;
7) Torch lock function indicator: Press “OPERATE” key, when this indicator is on, mean
it’s on “torch lock” status;
8) Torch unlock function indicator: Press “OPERATE” key, when this indicator is on,
mean it’s on “torch unlock” status;
9) Current display indicator light: Press “DISPLAY” key, when this indicator is on it,
means the digital displaying meter (Number 8) is displaying the current value. When
there is starting signal (No.11 indicator light is on), the output current value is
displaying, when it’s not starting, the pre-setting current value is displaying;
10) Gas pressure displaying indicator light: Press “DISPLAY” key, when this indicator is on
it, means the digital displaying meter (Number 11) is displaying the plasma gas
pressure value;
11) Digital displaying meter: Displaying current, plasma gas pressure, coolant flow,
parameters on secondary menu and error code;
12) Water coolant flow displaying indicator light: Press “DISPLAY” key, when this
indicator is on it, means the digital displaying meter（Number 11）is displaying the
water coolant flow value;
13) The “DISPLAY” key:
Function one: to swift the different displaying function of “A”/ “Mpa”/“L/min”
Function two: press this knob for 5s, machine come into Manual pump function, loose
the knob, out of the Manual pump function. Under Manual pump function, the pump
will continuously working only if the coolant flow is normal. When install the new
machine, this function can fill the machine cooling system and work normal, good for
the cooling system maintenance and repair.
Function three: under the second menu parameter setting status, press this knob for 7s

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to recovery all the second menu parameter to factory set data.
14) AIR PRESSURE indicator light：to indicate the status of plasma gas pressure.
If this indicator light is ON: means the plasma gas pressure ≥0.38MPa, it’s
normal.
The indicator light 0.3s on and 0.3s off (Quick flashing): means the plasma gas
pressure is in warning value range(0.3MPa≤air pressure＜0.38MPa ), now the
cutter can work, but the cutting quality may get bad, and the consumables may
burned faster;
The indicator light is off: means the plasma gas pressure ＜0.3MPa, now the
cutter stop working;
The indicator light 1s on and 1s off (Slow flashing): means the plasma gas
pressure was too low but back to normal now. And this slow flashing status will
keep 3 minutes. It’s normal.
15) COOLANT FLOW displaying indicator light : to indicate the torch coolant flow status.
If this indicator light is ON: means the coolant flow ≥2.7L/min, it’s normal.
The indicator light 0.3s on and 0.3s off (Quick flashing): means the coolant flow
is in warning value range(2.0L/min≤ coolant flow＜2.7L/min), now the cutter
can work, but the consumables may burned much faster;
The indicator light is off: means the coolant flow ＜2L/min, now the cutter stop
working;
The indicator light 1s on and 1s off (Slow flashing): means the coolant flow was
too low (＜2L/min )but back to normal now. And this slow flashing status will
keep 3 minutes. It’s normal.
16) START indicator light: When the light ON means the cutting machine got the starting
signal, start to cut;
17) OVER LOAD indicator light: when the inner cutter temperature is too high (Usually
when the cooling fan is broken), this indicator light flashing (Light on 0.3s and off
0.3s), and the cutter stop working. After the temperature is back to normal, the
indicator light will slow flash and start to work again;
18) INPUT FAULT indicator light: when the power supply is lower than 280VAC, this
indicator start flashing (0.3s on and 0.3s off) and stop working. After the power
input back to normal, the indicator light will slow flash and start to work again;
19) Cutting current adjusting knob: Adjusting cutting current; at the same time, it’s also
a choose key as secondary menu;
20) AIR COOLING torch indicator light：Press “TORCH” key, when this light is on, means

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the air cooling torch can be used, the maximum current will be limited under 160A;
21) WATRT COOLING torch indicator light ：Press “TORCH” key, when this light is on,
means the water cooling torch can be used;
22) TORCH selection key：
Function one: choose the air cooling or water cooling torch
Function two: take as a confirmation knob under the second menu
23) Cutting ground cable connection thread hole: To pass through the cutting ground
cable;
24) Coolant inlet connector : to connect the outlet pipe of the water cooling machine,
25) Coolant return connector: to connect the return pipe of the water cooling machine,
26) The power input connecting box: to connect the 3 phase power input;
27) Ground protection terminal;
28) Power switch: To control the ON/OFF of 3-phase power supply of cutter;
29) Control fuse holder;
30) The gas inlet: to connect the compressed air;
6.8 Protection function introduction
1) Air pressure protection
When the cutting air pressure is lower than 0.3MPa, the protection circuit starts
working and the cutter cannot start, and error code E80 will be displayed;
When the air pressure is lower than 0.3MPa during cutting, the protection
circuit starts working and the cutter cannot start, the cutting arc will extinguish
automatically;
Note: When adjust the air pressure, the panel function must be set to ‘GAS
TEST’！
2) Water pressure protection
When the water supply flow is lower than1.6L/min for LGK-200MA and 2L/min
for LGK-300/400MA, the COOLANT FLOW indicator light will not on, error code
E81, protection circuit starts working and cutter cannot start;
When the water supply is lower than above value for more than 2 hours, error
code E90, restart the machine, E90 not appear, cutting start
3) Over-heat protection
When the ambient temperature is too high or the cooling fan is broken, the cutter will be
over heated under the rated current, and heat protection circuit starts working, the cutting
arc will extinguish automatically;
4) Power supply input fault protection