Installation; Before Installation; Location; Airflow Considerations - Lincoln Electric MASTER LOAD IM575 Operator's Manual

3

BEFORE INSTALLATION

Inspect the Load Bank for obvious damage such as
broken wires, broken or dented panels, cracked
ceramic insulators, or any other component breakage
that may have occurred in shipment.

LOCATION

The Master Load 750 is a portable, indoor, outdoor
Load Bank, and should be installed in a dry, cool,
well-ventilated area. Cool air must be continually
available and the hot exhaust air must be dissipated,
not recirculated through the unit. Install the Load
Bank so that the inlet and exhaust panels have unre-
stricted airflow clearance.
CAUTION
Installation must prevent hot exhaust air from recircu-
lating into the air intake.
exceeding 120° F (50° C) may cause damage to the
Load Bank. After installation, test the unit at full load
and verify that the inlet air temperature does not
exceed 120° F (50° C).
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AIRFLOW CONSIDERATIONS

Even with an ample supply of cooling air, the load bank
may overheat if it is not properly installed. There are
two types of airflow problems that should be avoided:
1. Recirculating Airflow - If the hot, exhausted air
is permitted to recirculate through the load bank,
the air will reach such a high temperature and low
density that it will no longer cool the resistance
elements. A load bank should not be installed so
close to any surface as to reflect the exhausted air
back to the air intake. When two or more load
banks are being used, care must be taken in posi-
tioning the units so that the exhausted air of one
unit does not feed the air intake of another.
2. Restriction of Cooling Air - Any obstruction
located within 8 feet (2.4 m) of the inlet and
exhaust screens will restrict the load bank's air-
flow. Airflow is also restricted when two or more
load banks have air inlets positioned too close to
each other. This competition for cooling air caus-
es a low pressure area, restricting adequate air-
flow.
WARNING
It is important to install the Load Bank properly.
Installation errors may result in a catastrophic failure.

INSTALLATION

Inlet air temperatures
MASTER LOAD 750
The over temperature switch, a protective device in
the load bank, will guard against some of these prob-
lems. If protective circuitry prevents application of the
load, determine the source of the problem. DO NOT
DISABLE THE OVER TEMPERATURE SWITCH.
This causes a safety hazard and voids our warranty.
The following installation instructions are critical to the
safe operation of the Load Bank. Refer to the Load
Bank Safety section of this manual.
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POWER REQUIREMENTS

The Load Bank requires a 120 volt, single phase, 60
Hz, 15 amp source of power for operation of the con-
trol panel and cooling fan. A power cord for control
power is provided with the Load Bank. Connect the
power cord to a grounded 120 volt source.
Load power is connected to the Load Bank through
receptacles on the side of the Load Bank labeled L1
and L2.
WARNING
Do not energize the Load Bank with
the top cover removed. Make sure
the top cover panel is securely fas-
tened to the frame.
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Cables to the Load Bank should be of adequate size
to handle the maximum rated current according to the
National Electrical Code and any local codes.
ground stud is provided and must be connected to the
frame of the power source, which in turn must be con-
nected to a good earth ground.
WARNING
Never exceed the rated voltage as this will cause the
Load Bank to overheat.
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Lower voltages and different frequencies may be
applied to the load circuit of the Load Bank.
Frequency change causes no derating of the load;
however, the applied KW with a lower voltage is com-
puted by using the following formula:
KW Applied = KW Rated X
3
A
2
(Voltage Applied)
2
(Voltage Rated)