Mac Afric NBC-250 User manual

USER’S MANUAL
NBC –250
MIG/MMA/TIG WELDING MACHINE

WARNING:
while welding and cutting, please protect yourself, it may harm your body and others .
pls following our instructions:
Electricity may cause death!
⚫Following operation standard, install the earth setting.
⚫when skin is bare or workers wearing wet glove or wet clothes ,It is forbidden to touch
workpiece or electrode with electricity.
⚫Make sure you are insulate to the earth and the workpiece .
⚫make sure your working location is safe .
Arc –may harm your eye and burn your skin!
⚫Wearing suitable clothes and mask,glass, to protect your eye.
⚫Use suitable mask and blind to protect the person nearby.
⚫Welding may cause fire, so please make sure workplace nearby is without any tinder.
This welding machine is based on advanced inverter technology, installed special reactor inside,can
control short circuit in the welding process.compared with silicon control welding machine , the outgood
welding features is as following: stable feeder speed, light,energy –saving, without noise. Little
current can also works stable,more suitable for welding thin workpiece of low carbon steel,alloy,
stainless steel. Also can balance when the voltage is not stable, with little spatter,deep penetration
and high duty cycle.
Installation:
Euiped with voltage compensate system ,so the machine can work normally when the actual voltage
is ±15％than rated voltage.
In order to avoid voltage reducing,it is suggested to use bigger dimension cable when using longer cable.and
if the connecting cable is too long, it may affact arc striking and other performance.so we suggest you
use the suitable length as we recommend.
make sure the ventilate part is not blocked , or the cooling system may not work.
CAUTION!
USE THIS MACHINE SHOULD INSTALL ELECTRICITY LEAK
PROTECTION SWITCH !

TYPE MMA MIG TIG
Power voltage (V)：230 230 230
Rated input current(A)：36 33 25
Output current range(A)：20-250 20-250 20-250
No-load voltage(v)：65 65 65
Rated output voltang.(V)：30 26.5 20
Insulation class ：F F F
Efficiency(%)：85 85 85
Duty cycle (%)：60 60 60
Wire Diameter(mm)：--- 0.8-1.0 ---
ARC STARTING：TOUCH TOUCH HF
Dimension(mm)：570*305*518 570*305*518 570*305*518
Installation:
1. connect the gas cylinder to CO2 input part of machine by gas hose., the gas cylinder should have CO2 gas
pressure reducer.
2. connect the earth clamp to the connector on the panel
3. install the welding wire to the bracket.
4. choose the suitable gloove according to the wire diameter.
5. insert the wire to the feeder through gose, pls take care to avoid wire bend .
6. the wire should installed deasil, and use the scew to fix the wire. If the wire is bend ,pls cut off this part .
7. connect the torch to the socket on the panel, and connect the wire to the torch.
Operation:
1. locate “ON”of the air switch . adjust the gas bottle switch, and adjust the flowmeter.
2. choose the suitable diameter of feeder according to the wire .
3. choose the suitable contact tip .
4. adjust the voltage and current according to the workpiece.
5. press the switch of torch, then the wire can come out, and you can start

work now.
1) the working condition should be dry, air humidity should less than 90%
2) the temperature should around -100～400.
3) avoid work in the sun and rain, never let water go inside of the machine.
4) Avoid work in the dusty or cautic air.
5) Avoid working in strong air
Safety notice:
with over voltage,over current and over heat protection,the welding machine will stop working when
the voltage ,output current and heat is exceed the standard setting . But the machine may broken
by over loaded works (when the voltage is too high), so we need take care of following conditions :
1) Make sure the workplace is well ventilated. As the machine’s dimension is not so big, so the it
require better ventilation when strong current passed through . workers should make sure the
ventilate part is not blocked ,and the machine should keep 0.3 m away from other goods, in that
way, the machine can work better and can keep long working life.
2) Forbidden over load working workers shold check max load current (according to rated duty
cycle),keep the welding current less than max load current. Over load working will reduce life
of the machine,and may even burn it.
3) Avoid over voltage normally, voltage compensate circuit can ensure the welding current keeps in
standard scope.If the voltage is exceed, the machine may burned, so the user should notice it
and avoid it.
4) If the duty cycle is exceed , the welding machine may self protected and stop work .it means the
duty cycle is exceed, over heat protection works, so the machine stop working, and the red light
on the panel is on. In such case, you don't need cut off the power, you should let the fan work
and the machine will be cooled after some minutes. When the red light is off, the machine can continue
work again
The normal problem in welding process
The below problem may caused by accessory , the workpiece, the circumstance, the power
supply, etc, so you should provide good working condition ,avoid following problem.
A. strick arc difficulty and unstable arc .
（1）make sure the earth clamp and the workpiece is well connected.
（2）check every connection.
B. output current cant reach rated current.
The input voltage is not same as rated voltage , so the current is not same as the setting.
C. The current is not stable in welding.
The max output current less than rated, it may caused by below:
(1) The input voltage is changed
(2) The influence comes from electricity net and other equipments.
D. the welding slot is with gas bubble.
1) check the gas supply ,make sure no leak of gas.
2) Check the workpiece, make sure no oil, dusty on it.
Maintain:

Clean the dusty by air compresspor,especially work in polluted air ,you should clean at
least one time every day.
The compressed air should well adjusted and according to requirements, avoid small parts
inside broken.
Check the electricity and gas connection, make sure it is well fixed. if some parts i
s oxidized, pls grind these parts and connect again.
Avoid wet in inside of machine. If any water inside, shall test the insulation by
megameter,continue to use when it is acceptable.
If the machine cant work for a long time, you should packed the machine and locate it in
dry environment.
Workers should clear the dusty of motor on the feeder and paint oil on feeder roller ,after feeder
works every 300 hours .
CAUTION: make sure the electricity is cut off when doing
maintain work ,make sure the power plug is pulled out
before open the shell.