LOKERMANN GRAND ARC 400 CEL User manual

USER MANUAL
INVERTER Based Welding Machines
IMPORTANT: Read this OPERATOR MANUAL together
with PRESCRIPTION AND COMPLIANCE MANUAL before
to use this equipment. In case of loss one of two parts
contact immediately your dealer.
Allow the operator to consult this manual.
GRAND ARC
400 CEL

1 INSTALLATION WARNING
2 OVERVIEW
2.1 Features
2.2 Technical Data
2.3 Brief Introduction
2.4 Duty cycle and Over-heat
2.5 Working Principle
2.6 Volt-Ampere Characteristic
3 INSTALLATION & OPERATION
3.1 Layout for the front and rear panel
3.2 Installation & Operation for MMA Welding
3.2.1 Set up installation for MMA Welding
3.2.2 Operation for MMA Welding
3.2.3 MMA Welding
3.2.4 MMA Welding Fundamentals
3.2.5 MMA Welding trouble shooting
3.3 Installation & Operation for TIG Welding
3.3.1 Set up installation for TIG Welding
3.3.2 Operation for TIG Welding
3.3.3 TIG Welding Fundamentals
3.3.4 DC TIG Welding trouble shooting
3.4 Operation environment
3.5 Operation Notices
4 MAINTENANCE & TROUBLESHOOTING
4.1 Maintenance
4.2 Troubleshooting
4.3 List of error code
4.4 Electrical schematic drawing

1. Installation warning
This machine is certified according to 60974-10:2014 Arc Welding Equipment Part 10: Electromagnetic
compatibility (EMC) requirement and the EUT belongs to Group 2 Class A.
WARNING: This Class A equipment is intended for industrial use and it is not intended for use in
residential locations where the elctrical power is provided by the public low-voltage supply system.
There may be potential difficulties in ensuring electromagnetic compatibility in those locations, due to
conducted as well as radiated disturbances.
WARNING: This equipment does not comply with IEC 61000-3-12. If it is connected to a public low-
voltage system, it is the responsability of the installer or user of the equipment to ensure, by consultation
with the distribution network operator if necessary, that the equipment may be connected.
Assessment of area
Before installing arc welding equipment the user shall make an assessment of potential
electromagnetic problems in the surrounding area. The following shall be taken into account:
a) other supply cables, control cables, signalling and telephone cables, above, below and
adjacent to the arc welding equipment;
b) radio and television transmitters and receivers;
c) computer and other control equipment;
d) safety critical equipment, for example guarding of industrial equipment;
e) the health of the people around, for example the use of pacemakers and hearing aids;
f) equipment used for calibration or measurement;
g) the immunity of other equipment in the environment. The user shall ensure that other
equipment being used in the environment is compatible. This may require additional
protection measures;
h) the time of day that welding or other activities are to be carried out.
The size of the surrounding area to be considered will depend on the structure of the building
and other activities that are taking place. The surrounding area may extend beyond the
boundaries of the premises.
Methods of reducing emissions-Public supply system
Arc welding equipment should be connected to the public supply system according to this manual
recommendations. If interference occurs, it may be necessary to takeadditional precautions such as
filtering of the public supply system. Consideration should be given to shielding the supply cable of
permanently installed arc welding equipment, in metallic conduit or equivalent. Shielding should be
electrically continuous throughout its length. The shielding should be connected to the welding power
source so that good electrical contact is maintained between the conduit and the welding power
source enclosure.

Maintenance of the arc welding equipment
The arc welding equipment should be routinely maintained according to this manual
recommendations. All access and service doors and covers should be closed and properly
fastened when the arc welding equipment is in operation. The arc welding equipment should
not be modified in any way, except for those changes and adjustments covered in this manaul. In
particular, the spark gaps of arc striking and stabilising devices
should be adjusted and maintained according to our recommendations.
Welding cables
The welding cables should be kept as short as possible and should be positioned close
together, running at or close to the floor level.
Equipotential bonding
Bonding of all metallic objects in the surrounding area should be considered. However,
metallic objects bonded to the work piece will increase the risk that the operator could receive
an electric shock by touching these metallic objects and the electrode at the same time. The
operator should be insulated from all such bonded metallic objects.
Earthing of the workpiece
Where the workpiece is not bonded to earth for electrical safety, nor connected to earth
because of its size and position, for example, ship’s hull or building steelwork, a connection
bonding the workpiece to earth may reduce emissions in some, but not all instances. Care should be
taken to prevent the earthing of the workpiece increasing the risk of injury to users or damage to other
electrical equipment. Where necessary, the connection of the workpiece to earth should be made by
a direct connection to the workpiece, but in some countries where direct connection is not permitted,
the bonding should be achieved by suitable capacitance, selected according to national regulations.
Screening and shielding
Selective screening and shielding of other cables and equipment in the surrounding area may
alleviate problems of interference. Screening of the entire welding area may be considered for
special applications.

2 Overview
2
.1 Features

Capable of welding with Lift Tig Mode.

Designed for
using cellulose welding rods.

Selectable VRD Protection for increased safety.

Adjustable arc force, hot start & anti-stick for
greater control and ease of use .

Digital current display meter for accurate pre-
setting and feedback of welding param- eters &
output.

Phase loss protection prevents damage as
machine automatically shuts down if power
supply phase loss occurs.

Temperature, voltage and current sensors for
increased reliability & safety.

Light,weight and compact design, ideal for
portable applications

Designed to work with diesel generators and
to avoid failures due to its voltage spikes.

Power source wind tunnel cooling construction
for protection against environmental contamination
2.2 Technical Data
Models
Parameters
GRAND ARC 400 CEL
Power Supply Voltage (V) 3~380V/400V±10%
Frequency(HZ) 50/60
Rated input current(A) 38MMA/28 TIG
Rated input power（KW）16.1 MMA/11.7 TIG
Duty cycle (40℃10 min)60% 400A
100% 310A
Welding Current Range(A) 20-400
No Load Voltage(V) 94MMA/22 TIG
Efficiency(%) ≥80%
Power Factor 0.7
Insulation class H
Protection class IP23
Cooling
AF
Net Weight(Kg) 22
Dimensions(mm)
570*280*450
Electrode Diameter
φ1.6~φ6.0
Electrode Type 6010,6011,6013,7018 etc.
Note: The above parameters are subject to change with future machine improvement!

2
.3 Brief Introduction
M
MA series of welding machines adopt the latest Pulse Width Modulation (PWM) technology
a
nd the Insulated Gate Bipolar Transistor (IGBT) power modules. It uses switching frequencies in
t
he 20KHz-50KHz ranges so as to replace the traditional line-frequency transformer type welding
m
achines. Thus, machines are characterized with portability, small size, lightweight, low energy
c
onsumption and noise, etc.
M
MA series of welding machines has excellent performance: constant current output makes
w
elding arc more stab le; fast dynamic response speed reduces the impact from the arc length
f
luctuation to the current; accurate stepless current adjustment and pre-setting function. There are als
o
s
ome automatic protection functions for under voltage, over current, over heat, etc. inside the welder
,
w
hen the problems listed before occurred, the alarm light on the front panel is on and at the same
t
ime the output current will be cut off. It can self-protect, prolong the us efull life, greatly improved
t
he reliability and pract icality of the welding machine.
M
MA series of welding machines can also realize TIG operation. While MMA operation, if the
e
lectrode touches workpiece over two seconds, the welding current will drop to the minimum curren
t
a
utomatically to protect the electro de. While TIG operation, the minimum current will be outputted
f
irstly until the arc is ignited by lifting method, the output current will rise to the preset value, which
c
an protect the electrode.
M
MA series of welding machines is widely used in Petroleum, chemical, mechanical,
s
hipbuilding, architecture, boiler, pressure container, military industry and Maintenance work, etc.
T
his machine has high duty cycle even in the 40℃, which can keep the continuous operation. The
f
rame is Stability of the machine,which can keep working under high temperature and corrosion
e
nvironment.
MMA: Manual Metal Arc welding;
PWM: Pulse-Width Modulation;
IGBT: Insulation Gate Bipolar Transistor;
TIG: Tungsten Inert Gas welding.
2
.4 Duty cycle and Over-heat
T
he letter “X” stands for Duty Cycle, which is defined as the portion of the time a welding machine
c
an weld continuously with it’s rated output current within a certain time cycle (10 minutes).
T
he relation between the duty cycle “X” and the output welding current “I” is shown as the right
f
igure.
I
f the welding machine is overheating, the IGBT over -heat protection sensing will send a signal to
t
he welding machine control unit to cut the output welding current OFF and light the over-heat pilot
l
amp on the front panel. In that case, the machine should not be welding for 10-15 minutes to cool
d
own with the fanrunning. When operating the machine again, the welding output current or the dut
y
c
ycle should be reduced.

2
.5 Working Principle
T
he working principle of MMA series of welding machines is shown in the following figure. Three-
p
hase 380V line frequency AC is rectified into DC, then is converted to medium frequency AC by
i
nverter device (IGB T), after reducing voltage by medium transformer (the main transformer) and
r
ectified by medium frequency rectifier (fast recovery diode), and is outputted by inductance filtering.
T
he circuit adopts current feedback control technology to insure current output stability. Meanwhile,
t
he welding current parameters can be adjusted continuously and steplessly to meet with the
r
equirements of welding craft.
2
.6 Volt-Ampere Characteristic
M
MA series of welding machines has excellent volt-ampere characteristic. Referring to the
f
ollowing graph. In MMA welding, the relation between the rated loading voltage U2and welding
c
urrent I2 is as follows:
When I2≤600A，U2＝20＋0.04 I2（V）；When I2＞600A，U2＝44（V）.
66
44
20
0 600 I
2
（A）
U
2
（V）
Working
point
Volt-ampere characteristic
The relation of the rated loading
voltage&welding current
Rectify Inverter
Medium
frequency
transformer
Medium
frequency
rectify
Hall device
Current positive-
feedback control
Three-phase, AC DC AC DC
380V，50Hz
AC DC
U0

3 Installation & Operation
3
.1 Layout for the front and rear panel
（1）Negative (-) welding power output connection socket.
（2）Positive (+)
（3）Input power cable.
（4）Power switch: control the power Supply on and off.
（5）Welding current control knob.
（6）Digital current display meter.
（7）Power indicator: Lights when input power connected and machine switched on.
（8）Alarm indicator. *
（9）Welding output mode button: Sets power source in MMA, MMA VRD* or
Lift TIG* mode.
（10）MMA mode indicator.
（11）MMA VRD mode indicator.
（12）Lift TIG mode indicator.
（13）Arc Force control knob. *
（14）Hot Start control knob. *
*Denotes more detailed explanation of function to follow.
F
urther Controls Explained
A
larm indicator
L
ights when over voltage, over current, input phase loss or electrical overheating (due to
e
xceeding duty cycle) is detected and protection is activated.
W
hen protection is activated, welding output will be disabled until the safety system senses
t
he overload has reduced sufficiently and indicator lamp goes out. May also trigger if machine
e
xperiences an internal power circuit failure.
welding power output connection socket.

A
rc Force control knob
A
n MMA welding power source is designed to produce constant output current (CC). This mean
s
w
ith different types of electrode and arc length; the welding voltage varies to keep the current
c
onstant. This can cause instability in some welding conditions as MMAwelding electrodes will hav
e
a
minimum voltage they can operate with and still have a stable arc.
A
rc Force control boosts the welding power if its senses the welding voltage is getting too low. The
h
igher the arc force adjustment, the higher the minimum voltage that the power source will allow.
T
his effect will also cause the welding current to increase. 0 is Arc Force off, 10 is maximum Ar
c
F
orce. This is practically useful for electrode types that have a higher operating voltage requirement
o
r joint types that require a short arc length such as out of position welds.
H
ot Start control knob
H
ot start provides extra power when the weld starts to counteract the high resistance of the electrod
e
a
nd workpiece as the arc is started.
L
ift TIG Mode
L
ift TIG is an arc ignition system for basic TIG welding that removes the need to “scratch”
s
tart or strike the tungsten on the work piece to start the arc, which can have a negative effect on
t
he weld quality due to tungsten contamination. Lift arc starting works by gently touching the
t
ungsten on the work piece andthen lifting it off. The control circuit will sense whenthe tungsten
i
s removed from the work piece and send a pulse of electricity through the torch that will cause
t
he TIG arc to initiate.
V
RD Function
V
RD stands for Voltage Reduction Device. This is a safety system that reduces the output voltage
f
rom the welding terminals in MMA mode while the welding output is not in use, to reduce the risk
o
f electric shock from the live output voltage. The disadvantage of this system is that it makes the
s
triking of the arc more difficult, especially on restarts and with some types of electrode such as low
h
ydrogen electrodes.
3
.2 Installation & Operation for MMA Welding
3.2.1 Set up installation for MMA Welding
C
onnection of Output Cables Two sockets are available on this welding machine. For MMA weldin
g
t
he electrode holder is shown be connected to the positive socket, while the earth lead (work piece)
i
s connected to the negative socket, this is known as DCEP. However various electrodes require a
d
ifferent polarity for optimum results and careful attention should be paid to the polarity, refer to th
e
e
lectrode manufacturers information for the correct polarity.
D
CEP: Electrode connected to “+”output socket.
D
CEN: Electrode connected to“-”output socket.

(
1) Connect the earth lead to “-”,tighten clockwise;
(
2) Connect the earth clamp to the work piece. Contact with the work piece must be firm contact
with clean, bare metal, with no corrosion, paint or scale at the contact point.
(
3) Connect the electrode lead to “+”,tighten clockwise;
(
4) Each machine is equipped with a power cable should be based on the input voltage welding
power cable connected to the appropriate position, not to pick the wrong voltage;
(
5) With the corresponding input power supply terminal or socket good contact and prevent
oxidation;
(
6) With a multi meter measure the input voltage is within the fluctuation range;
(
7) The power ground is well grounded.
3.2.2 Operation for MMA Welding
(
1) According to the above method to install is correct, turn the power switch, so that the power
switch is “ON” position, then the power indicator light, the fan comes on, the device work
properly.
(
2) Select the MMA /MMAVRD function with the LIFT TIG/MMA/MMA VRD selector switch.
(
3) Set the welding current relevant to the electrode type and size being used as recommended by
the electrode manufacturer.
(
4) Set welding parameters (hot start and arc force) as required following instructions in the previou
s
section.
(
5) Place the electrode into the electrode holder and clamp tight.
(
6) Strike the electrode against the work piece to create and arc and hold the electrode steady to
maintain the arc.
(
7) Commence welding. If necessary, readjust the Weld Current control to obtain the welding
condition required.
(
8) After completion of welding the Power Source should be left turned ON for 2 to 3 minutes. Thi
s
allows the fan to run and cool the internal components.
(
9) Switch the ON/OFF Switch (located on the rear panel) to the OFF position.