Zenit Powertools MMA-300/2 PROFI User manual

InstructIon manual
Inverter weldIng machIne
mma-300/2 profI
SEMI-PROFI SERIES

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General safety precautions
WARNING! When using electric
tools, basic safety precautions should
always be followed to reduce the risk of
re, electric shock and personal injury,
including the following.
Read all these instructions before
operating this product and save these
instructions.
For safe operations:
1. Keep work area clean. Cluttered areas
and benches invite injuries.
2. Consider work area environment. Do
not expose power tools to rain. Do not
use power tools in damp or wet locations.
Keep work area well lit. Do not use
power tools where there is risk to cause
re or explosion.
3. Guard against electric shock. Avoid
body contact with earthed or grounded
surfaces. (e.g. pipes, radiators, ranges,
refrigerators).
4. Keep children and inrm persons
away. Do not let visitors touch the tool
or extension cord. All visitors should be
kept away from work area.
5. Store idle tools. When not in use, tools
should be stored in a dry, high or locked
up place, out of reach of children and
inrm persons.
6. Do not force the tool. It will do the job
better and safer at the rate for which it
was intended.
7. Use the right tool. Do not force small
tools or attachments to do the job of a
heavy duty tool. Do not use tools for
purposes not intended.
8. Dress properly. Do not wear loose
clothing or jewelry; they can be caught
in moving parts. Rubber gloves and non-
skid footwear are recommended when
working outdoors. Wear protecting hair
covering to contain long hair.
9. Use eye protection. Also use face or
dust mask if the cutting operation is
dusty.
10. Connect dust extraction equipment. If
devices are provided for the connection
of dust extraction and collection facilities
ensure these are connected and properly
used.
11. Do not abuse the cord. Never
carry the tool by the cord or yank it to
disconnect it from the receptacle. Keep
the cord away from heat, oil and sharp
edges.
12. Secure work. Use clamps or a vise to
hold the work. It is safer than using your
hand and it frees both hands to operate
tool.
13. Do not overreach. Keep proper
footing and balance at all times.
14. Maintain tools with care. Keep
cutting tools sharp and clean for
better and safer performance. Follow
instructions for lubrication and
changing accessories. Inspect tool cords
periodically and if damaged, have it
repaired by authorized service center.
Inspect extension cords periodically and
replace, if damaged. Keep handles dry,
clean, and free from oil and grease.
15. Disconnect tools. When not in use,
before servicing, and when changing
accessories such as blades, bits and
cutters.
16. Remove adjusting keys and wrenches.
Form the habit of checking to see that
keys and adjusting wrenches are removed
from the tool before turning it on.
17. Avoid unintentional starting. Do not
carry a plugged in tool with a nger on
the switch. Ensure switch is off when
plugging in.
18. Use outdoor extension leads. When
tool is used outdoors, use only extension
cords intended for outdoor use.
19. Stay alert. Watch what you are doing.
Use common sense. Do not operate tool
when you are tired.
20. Check damaged parts. Before further

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use of the tool, a guard or other part that
is damaged should be carefully checked
to determine that it will operate properly
and perform its intended function.
Check for alignment of moving parts,
free running of moving parts, breakage
of parts, mounting and any other
conditions that may affect its operation.
A guard or other part that is damaged
should be properly repaired or replaced
by an authorized service center unless
otherwise indicated in this instruction
manual. Have defective switches replaced
by an authorized service center. Do not
use the tool if the switch does not turn it
on and off.
21. Warning Use only accessories
or attachments recommended in this
instruction manual or in the catalogue of
ZENIT ТМ.
22. Have your tool repaired by a qualied
person. This electric tool is in accordance
with the relevant safety requirements.
Repairs should only be carried out by
qualied persons using original ZENIT
TM spare parts. Otherwise this may result
in considerable danger to the user.
WARNING! Carefully read the following
instructions before operating the
unit. Nonobservance of the following
precautions will make the safety system
provided by the manufacturer ineffective,
which in its turn may cause serious injury
(electric shock, burns) or cause re.
General information
Welding inverter is a rectier of the
regulated current and is intended for arc
direct current welding, controlled by
bridged transistor.
Specications of the welding inverters:
• High speed and welding current
adjustment accuracy, which provide
high welding quality using a welding
electrode.
• Welding inverter increases mains
frequency from 50 Hz to more than
15 kHz, steps down the voltage and
generates power direct current for
welding by pulse-length modulation
principle.
• Inverter system also allows reducing
size of the transformer and reactance.
Such reduction of volume and weight
improves mobility and increases
performance.
Welding inverters poses other advantages,
as: arc stability, easy molten pool control,
easy installation and operation, high
quality and wide application area.
Safety precautions on using welding
inverter
• Avoid direct contact with welding
circuit. In quiescent mode the current
generated by alternator can be dangerous.
• Before installation and maintenance
unplug the machine from the mains
power supply.
• Perform connection according to
general safety precautions.
• The welding machine must be
grounded.
• Ensure the mains receptacle is
grounded.
• Never operate the machine in wet
conditions. Never operate under the rain.
• Never operate with damaged insulation
or loose connections.
• Never weld containers, tanks or pipes,
containing inammable materials, gases
or inammable liquids.
• Avoid welding materials cleaned with
chlorinated solvents as well as in the
proximity of such solvents.
• Remove all inammable materials
(wood, paper etc.) from the working area.
• Provide adequate level of air circulation
or ways of exhaust of fumes.
• Protect eyes with lter goggles,
installed on a mask or hard hat. Use
protective clothing.
• Never use welding machine for

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defrosting pipes.
• To avoid turning over install the
machine on even surface.
Description
1. Positive socket (+) for connecting
cable with electrode holder.
2. Negative socket for (-) for connecting
cable with functional terminal.
3. Potentiometer with a scale. Allows
adjusting welding current.
4. Thermostatic indicator. Indicator is
off when the machine operates normally.
Lit indicator means that temperature
inside the machine is exceeded and the
thermic protection has been activated.
The machine is on but not powered
until normal temperature is reached.
After cooling the machine will start
automatically.
5. Power indicator.
6. «On/Off» switch is on the back panel
of the welding machine.
technical specifications
Model MMA-300/2
pro
Rated power 7.5 кW
Rated voltage 220-240 V
Rated frequency 50-60 Hz
Current control range 20-300 А
Performance index 85%
Operating cycle* 75%
Power rate 0.93
Electrodes 1.6 - 5.0 mm
Net weight 5.2 kg
*Operating cycle: shows the period,
within which the machine can generate
corresponding current. It is expressed in
%, based on 10 minutes per cycle e.g.:
60% = 6 minutes of operation, 4 minutes
of waiting etc.).
installation place
Install the machine in such a way so that
ventilation openings are not obstructed
(forced circulation). Do not allow
aggressive steam, dust, humidity etc.,
inside the machine.
Fuse nomi-
nal, A
Welding
current, A
Receptacle
capacity, A
Cable sec-
tion, mm
16 130 16 16
20 160 32 16
20 180 32 25
25 200 32 25
Before connecting ensure that voltage,
indicated on the machine nameplate,
complies with the voltage and frequency
of the mains.
connectinG welDinG cables
Any connection to the welding circuit
must be performed when the machine is
disconnected from the supply line.
Welding cable with electrode holder is
connected to the positive pole (+) (see
«Welding»).
Cable with functional terminal is
connected to the negative pole (-), its

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other end is connected to the piece to be
welded or operating area as close to the
welding seam as possible.
WARNING! Connected cables
must be inserted securely in the
terminals, which will ensure good
contact. Loose connections will lead to
overheating, timely wear, loss of
efciency and damage to the terminals.
Do not use welding cables of more than
10 m in length.
Never use metallic constructions which
are not the part of the piece to be welded
instead of cable with functional terminal,
as this will violate safety and lead to poor
welding.
welDinG
WARNING! Most welding electrodes are
connected to the positive pole, although
some types have to be connected to
the negative pole. It is important to
follow manufacturer’s instructions on
the package of the electrodes, as they
indicate right polarity of the welding
electrode as well as the most suitable
current for welding operations.
Adjust welding current according to
diameter of used electrode and according
to type of welding seam. Below is the
table of admissible current according to
diameter of the electrode:
Electrode
diameter, mm
Welding current, А
Min Max
1,6 25 50
2 40 80
2,5 60 110
3,2 80 160
4 120 200
Pay attention, that depending on the
diameter of the electrode, higher values
of welding current are used for welding
in lower position, whereas vertical
welding (or welding in vertical position,
so called «overhead welding») requires
lower values of welding current.
Except for welding current power
mechanical characteristics of the welding
seam are determined by other parameters:
- diameter and quality of the electrode;
- arc length;
- speed and position of welding;
- proper storage of electrodes (they
must be protected from environmental
exposure and kept in a special package).
welDinG
When welding ALWAYS wear protecting
mask with special goggles for eye
protection from strong light emission,
generated by electric arc. Mask allows
watching the process of welding and
protects the user.
Keeping mask IN FRONT OF YOUR
FACE, lead the electrode on welding
area. Hand movement must resemble
lighting a match. This is the right way to
strike the arc.
WARNING! Never knock with
electrode trying to strike the arc, as this
may lead to its damage and will hamper
arc striking.
As soon as the arc is struck, try keeping
the distance from welding point equal
to electrode diameter. Remember that
electrode angle when moving should be
20-30 degrees.
After making welding seam move the

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electrode back. This is necessary for
lling the welding crater.
DanGerous factors when
performinG welDinG
operations
Fire prevention
• All inammable materials should be
removed from the welding area.
• Do not strike the arc on a gas tank or
near it.
• Never attempt to weld fuel tanks or
tanks lled with gas unless all measures
are taken to guarantee that they contain
no fumes.
• Before welding fuel tanks they must be
thoroughly cleaned with steam.
Welding fumes
When welding, toxic fumes are emitted.
Always work in well ventilated areas.
Electric arc light
Always use protecting mask or welding
helmet, equipped with corresponding
glass lter. Never use damaged safety
equipment.
High temperature
Use protective gloves. They provide
hands protection from ultra-violet light
and heat, emitted by electric arc. It is
recommended to wear special clothing.
aDDitional protective
cloths
When welding with heavy current use
protecting apron, which will protect you
from spatter.
When performing overhead welding use
adequate head wear, which will protect
your head and neck.
It is recommended to wear closed safety
boots with steel toe caps.
welDinG seam specifications
Electrode movement is too slow
Very short arc
Very low welding current
Electrode movement is too fast
Very long arc
Very high welding current
Normal seam
maintenance
WARNING! Before disassembling
any panel of the machine for performing
any operations inside disconnect the plug
from the receptacle.
Regularly, depending on usage in dusty
environment, perform maintenance of
the machine internals. Remove dust from
internal components of the machine with
low pressure air ow.
After maintenance reinstall panels and
tighten screws.
Never perform welding when the
machine is open!
troubleshootinG
Before contacting service center
for technical assistance perform the
following checks:
• Ensure the welding current regulated by
potentiometer corresponds the diameter
and type of the used electrode.
• Power indicator (On) shall not lit when
there is power failure (check cables,
outputs, fumes etc.).
• Yellow indicator shows overheating,
short circuit, too low or too high voltage.
• Check voltage of the power line.
Machine will not work if the voltage is
too low or too high. Machine will start
automatically only if voltage returns back
to normal level.

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• Ensure that there is no short circuit on
the output of the machine. Otherwise
eliminate the defect.
• All connections of the welding circuit
must be operational, and functional
terminal must be securely xed to the
work piece to be welded.
CAUTION
When using the drill follow these rules:
• do not allow mechanic damage (bumps,
falls etc.);
• protect the tool from external sources of
heat and chemically active substances, as
well as liquid and objects penetration;
• provide effective cooling and wastes
withdrawal from the tool working zone;
• before disconnecting the tool from the
power source turn off the On/Off switch;
WARNING! Repair, modication
and check of ZENIT power tools should
be performed only in authorized service
centers ZENIT. While use or maintenance
of power tools follow all safety rules and
standards.
NOTE
Zenit Power Tools are constantly being
improved and modied to incorporate the
latest technological advancements.
Accordingly, some parts may be changed
without prior notice.

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Demix LLC
Head ofce:
14, Shevchenko str., 3rd oor
Dnepropetrovsk, Ukraine, 49044
tel./fax: [phone]
http://www.en.zenit-pro.com