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Introduction
PRESTO 275
is a SMAW and GTAW power source
The complete package contains:
Power
source
USB
with
operator’s
manual.
Recommended equipment, which can be bought by user,
was mentioned in the "Accessories" chapter.
Installation and Operator Instructions
Read this entire section before installation or operating the
machine.
Exploitation conditions
This machine can operate in harsh environments.
However, it is important to use the following simple
preventive measures that will ensure its long life and
reliable operation:
Do not place or operate this machine on a surface with
an incline higher than 15° from horizontal.
Do not use this machine for pipe thawing.
This machine must be located where there is free
circulation of clean air without restrictions for air
movement. Do not cover the machine with paper, cloth
or rags when switched on.
Dirt and dust that can be drawn into the machine
should be kept to a minimum.
This machine has a protection rating of IP23. Keep it
dry when possible and do not place it on wet ground
or in puddles.
Locate the machine away from radio controlled
machinery. Normal operation may adversely affect
the operation of nearby radio controlled machinery,
which may result in injury or equipment damage.
Read the section on electromagnetic compatibility in
this manual.
Do not operate in areas with an ambient temperature
greater than 40°C.
Duty cycle and Overheating
The duty cycle of a welding machine is the percentage of
time in a 10 minute cycle at which the welder can operate
the machine at rated welding current.
Example: 60% duty cycle:
Welding for 6 minutes.
Break for 4 minutes.
Excessive extension of the duty cycle will cause the
thermal protection circuit to activate.
Minutes
or decrease
Duty Cycle
Input Supply Connection
WARNING
Only a qualified electrician can connect the welding
machine to the supply network. Installation had to be
made in accordance with the appropriate National
Electrical Code and local regulations.
Check the input voltage, phase and frequency supplied to
this machine before turning it on. Verify the connection of
ground wires from the machine to the input source. The
welding machine
PRESTO 275
must be connected to a
correctly installed plug-in socket with an earth pin.
Input voltage is 400 Vac 50/60Hz. For more information
about input supply refer to the technical specification
section of this manual and to the rating plate of the
machine.
Make sure that the amount of mains power available from
the input supply is adequate for normal operation of the
machine. The necessary delayed fuse or circuit breaker
and cable sizes are indicated in the technical specification
section of this manual.
WARNING
The welding machine can be supplied from a power
generator of output power at least 30% larger than input
power of the welding machine.
WARNING
When powering the machine from a generator be sure to
turn off welder first, before generator is shut down, in
order to prevent damage to welder!
