Lincoln Electric IDEALARC DC-1000 Service Manual page 26

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SAFETY PRECAUTIONS
WARNING
ELECTRIC SHOCK can kill.
• Only qualified personnel should
perform this installation.
• Turn the input power OFF at the
disconnect switch or fuse box before
working on this equipment.
• Do not touch electrically hot parts.
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GENERAL MAINTENANCE
1. The fan motors have sealed bearings which require
no service.
2. In extremely dusty locations, dirt may clog the air
channels causing the welder to run hot. Blow out
the welder with low pressure air at regular intervals
as required to eliminate excessive dirt and dust
buildup on internal parts.
OVERLOAD PROTECTION
The power source is thermostatically protected with
two proximity thermostats against overload or insuffi-
cient cooling. One thermostat is located on the trans-
former secondary Negative Output Lead, and the other
thermostat is located on the choke coil. The ther-
mostats are connected in series in the machine control
circuit so that if an excessive overload is applied to the
machine, or the machine should receive insufficient
cooling on either the main transformer, SCR bridge
assembly or choke, the input contactor would open
and remain open until the machine cools. It can then
be manually restarted by operating the start push but-
ton.
The power source is also protected against heavy
overloads on the SCR bridge assembly through an
electronic protection circuit. This circuit senses an
overload on the power source and opens the input con-
tactor should the overload remain for a predetermined
time. The predetermined time varies with the amount of
overload; the greater the overload, the shorter the
time. The input contactor will remain open until the
power source is manually started with the start push
button.
MAINTENANCE
The control board is designed with adequate protection
so that no damage will occur if the remote control leads
are shorted together or are grounded to the case. The
machine will automatically shut down if such faults do
occur.
An 8-amp fuse located on the machine control panel
protects the 115 volt auxiliary AC circuit (#31 and #32)
from overload. If replacing, use the same type and size
fuse.
IDEALARC ® DC-1000
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