Unitor UWI 320 TP Instruction Manual

Revision date: 23/09/2014 Page 1 of 24

Instruction manual

Unitor Welding Inverter

UWI 320 TP

MMA (Stick) and TIG welder

Revision date: 23/09/2014 Page 2 of 24

CONTENTS

1. GENERAL DESCRIPTION

2. TECHNICAL DATA

3. INSTALLATION

4. FRONT AND BACK PANEL

5. WELDING

6. ROUTINE MAINTENANCE

7. TROUBLESHOOTING

8. WIRING DIAGRAM

9. COMPONENTS AND SPARES

10. ACCESSORIES

11. SAFETY INSTRUCTIONS

DO NOT INSTALL, OPERATE OR REPAIR THIS EQUIPMENT WITHOUT

READING THIS MANUAL INCLUDING THE SAFETY INSTRUCTIONS

Revision date: 23/09/2014 Page 3 of 24

1 GENERAL DESCRIPTION

Connects to any primary voltage between 380 and 440V without need for any action from the
operator.

Line Voltage compensation keeps output of the power source constant regardless of fluctuation in
input power from 10% below lowest to above highest rated input voltage.

Safe in use. Touchable Open Circuit Voltage only 9V, well below the 70V limit set by the Code of
Safe Working Practices for Merchant Seamen.

Automatic Hot Start for stick arc starts makes arc striking easy and prevents electrode sticking.
Adjustable Arc Force for stick electrode welding allows the arc characteristics to be changed for

specific applications and electrodes.
Lift-Start in TIG mode provides easy and soft TIG arc starting.
Step-less adjustment of welding current through whole current range: 10 –320A.
Casing of high grade aluminium and industrial plastic to eliminate corrosion damage also contributes

to low-weight which together with compact outer dimensions provides good portability.
Wind tunnel design for the internal cooling air flow protects electrical components and PC boards

from dirt, dust, debris, greatly improving reliability.
Thermal overload protection with indicator lights helps prevent machine damage if the duty cycle is

exceeded or airflow is blocked.
Total Protection function with indicator light prevents machine damage if one phase in the primary

power supply falls out.
IDENTIFY COMPONENTS

Unitor Welding Inverter UWI 320TP, product number 191- 320320 is delivered with

1

Carrying strap mounted on the machine

1 pce

2

4 m primary cable, mounted on the welding machine, plug
not included.

1 pce

3

Instruction Manual

1 pce

2 3 1

Revision date: 23/09/2014 Page 4 of 24

2 TECHNICAL DATA

Type of welding machine

Three-phase static transformer rectifier

frequency converter, DC output.

Processes

MMA (Stick electrode / SMAW) TIG (GTAW)

Safety Marking

Suitable for use in areas with increased electric shock hazard

X: Duty cycle

Duty Cycle is percentage of 10 minutes that unit can weld at rated load without overheating.
It refers to a 40°C environmental temperature. If unit overheats a thermal switch stops the output, the
warning light for over-temperature is lit and the cooling fan continues to run. Wait fifteen minutes for
unit to cool. Reduce amperage or duty cycle before starting to weld.

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I2= Welding current.
Range 10 – 320A

Ur = No-load voltage

Is the voltage between welding terminals (touchable voltage) when the machine is idle and equipped
with a voltage reduction function for operator safety. Low value means high operator safety, and with
this in mind this machine satisfies the world’s strictest regulation: AS 1674.2-2007 Safety in welding
and allied processes (Australian standard) which allows for maximum 35V.

U0 = Arc striking voltage

When electrode touches work piece the Ur voltage will within a split second jump to this value. It is
important that this value is high enough to enable quick and easy arc start for all welding
consumables.

U2 = Arc voltage

Voltage present between the output outlets when welding is being carried out, in relation to a
particular set current. The relation, for the various welding modes is the following:
MMA→U2=(20+0,04*I2)
TIG →U2=(10+0,04*I2)

Primary connection

U1 = Effective input voltage 380 – 440V
I1max = Maximum value of input current at the corresponding duty cycle.
I1eff = Effective value of input current at the corresponding duty cycle.
Maximum input power is 14,9 kVA. Power factor 0,77. Duty Cycle 30%

Cooling

COOLING AF= Forced air cooling (with a fan).

Protection class

IP23S= Ingress Protection class. Protection degree of the casing according to EN 60529
2: Protection against intrusion of object greater than 12,5mm in diameter
3: Protection from sprayed water at an angle of 60º from vertical
S: Valid at standstill. (Should not be used for welding outdoors in heavy wind and rain)

Thermal insulation class

I.CL.H= Thermal class of the insulating materials and insulation systems.
resistant up to 180°C.

Standards

EN 60974-10 European Norm for electromagnetic compatibility.
EN 60974-1 European Norm for arc welding appliance: Current sources for welding.
Mark stating conformity to all safety standards and other standards required for sale

within the European Union

Dimensions and weight

Height : 325mm
Length : 460mm
Width : 230mm
Weight : 18,0kg

Revision date: 23/09/2014 Page 6 of 24

3 INSTALLATION

Only qualified personnel should perform this installation.
Only personnel that have read and understood this Manual should install and operate this
equipment.
Machine must only be plugged into a receptacle which is grounded in accordance with valid
regulations.

Note

The power switch should be in the OFF position when installing work cable and electrode cable and
when connecting power cord to input power.

Select a suitable location

The UWI 320 TP inverter welder has an IP23S rating. Locate the welder in a dry location where there
is free circulation of clean air into the louvers in the back and out the front of the unit.

Ensure minimum 50cm free space on all sides. If free flow of air is hindered the machine will
overheat.

A location that minimizes the amount of smoke and dirt drawn into the louvers reduces the chance of
dirt accumulation that can block air passages and cause overheating.

Avoid tilting

The machine must be placed on a secure, level surface, maximum 15º out of horizontal.

Assembly

Select polarity to electrode based on recommendations on the electrode package and the job at
hand. For GTAW (TIG) welding negative (-) polarity should always be to the torch.

3 phase 380-440V

50/60 Hz + PE

(10 A slow fuses

recommended)

Welding cable and

electrode holder

Return cable and

ground clamp

Work Piece

Negative pole

Positive pole

Revision date: 23/09/2014 Page 7 of 24

4 FRONT AND BACK PANEL

Description

1. Active VRD signal. When lit this shows that the Voltage Reducing Device is active, reducing
the voltage across the welding sockets. This will happen within 2 seconds after the welding
arc is broken to protect the welder from electric chock.
Full arc striking voltage will automatically be re-established when the welding circuit is re­established by touching the electrode to the work-piece

2. Remote control signal. Will be lit when a remote control is connected and remote adjustment
is selected at the back of the machine.

3. Power on warning. Green light when the machine is connected and switched on.

4. Thermal protection activated. Yellow light indicates that the protection thermostat has cut the
output. Do not switch the machine off. The fan will be running and the thermostat resets
automatically when the machine has cooled down sufficiently. The light will darken when the
machine is live again.

5. Selection of welding process:
Up: SMAW (MMA) welding with stick electrodes

Down: GTAW (TIG) welding.

6. Welding current adjustment potmeter. Rotate knob clockwise to increase amperage,
minimum to 320 Ampere

7. Arc force increases the short circuit amperage providing a crisper arc, allowing the welder to
use very short arc without sticking the electrode in the melt pool. It is useful when welding
with stick electrodes at low amperages but gives more spatter. Set control to 0 (soft arc) for
normal electrode welding and TIG welding.

8. On/Off switch (Back panel)

9. Primary cable, 4 core 2,5mm², 3m long.

10. When lit the Total Protection function

has been activated due to one missing

phase in the power supply to the machine.

11. Selection of welding current adjustment:

- On front panel

- With remote control

12. Socket for remote control.

11

12

8

10

9

1 3 2 4 5

6

7

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5 WELDING

MMA (SMAW stick electrode) welding

Select MMA welding (selector switch up).
Connect ground (return) cable with good contact to
the work piece.
Select polarity and amperage as recommended for
the electrode and start arc as follows:
Drag electrode across work piece like striking a
Match and lift electrode slightly after touching work.
If arc goes out electrode was lifted to high.
If electrode sticks to work piece, use a quick twist to
free it.

Hot start

The machine has automatic Hot Start for stick electrode welding. This makes arc striking easier and
reduces the possibility of electrode sticking

Arc Force

Use no or low Arc Force setting for smooth running electrodes like LH and SPECIAL.
Increased setting provides optimal characteristics for stiffer, more penetrating electrodes like E6010
types, chamfering electrodes like CH2 and electrodes for ACA gouging. It may also be an advantage
im position welding

TIG (GTAW) welding

Select TIG process (selector switch down) and connect TIG torch to negative (-) terminal on the
machine. The torch should preferably have gas valve on the handle. Connect ground (return) cable
with good contact to the work piece.

When the TIG process is selected normal open-circuit voltage is not present before tungsten
electrode touches and lifts from work piece. Only a low sensing voltage is present between
electrode and work piece.
The solid-state output contactor does not energize until after electrode is touching work piece.
This allows the electrode to touch the work piece without overheating, sticking, getting contaminated
or contaminate the work piece.

Start the arc as follows:

 Turn gas on.
 Touch tungsten electrode to workpiece at weld start point.
 Hold electrode to workpiece for 1-2 seconds, and slowly lift electrode.

The arc is formed when the electrode is lifted.

.

1 Electrode
2 Workpiece
3 Arc

1 Electrode
2 Workpiece

Lift carefully and the arc will

be established

Touch the electrode to the work
piece. Only sensing voltage will