Miller Electric RHC-3GD25B - Manual (Page 5)

OM-823 Page 2
SECTION 3 − OPERATOR CONTROLS
3-1. OPERATION
A. General
When a Remote Hand Control is being used, it should
be noted that on most welding power sources or welding
generators, the Remote Hand Control functions as a
fine amperage or voltage adjustment of the Amperage
or Voltage Adjustment Control setting on the welding
power source or welding generator. For example, if the
Amperage or Voltage Adjustment Control on the weld-
ing power source or welding generator is set at the mid-
point position, the Remote Hand Control will provide
(from its minimum to maximum positions) fine adjust-
ment of one half of the welding power source or welding
generator output. If full adjustment of the maximum out-
put of the welding power source or welding generator
from the Remote Hand Control is desired, it will be nec-
essary to rotate the Amperage or Voltage Adjustment
Control on the welding generator to the maximum posi-
tion. The Remote Hand Control dial is calibrated in per-
centage in increments of ten from 0 to 100 percent.
On some welding power source or welding generators
the Amperage Voltage Adjustment Control on the Weld-
ing power source or welding generator is inoperative
when a Remote Hand Control is connected in the weld-
ing power source or welding generator control circuitry.
In this situation, the Remote Hand Control provides
complete control from the minimum to the maximum
output of the welding power source or welding generator
rather than fine adjustment of the Amperage or Voltage
Adjustment control setting on the welding power source
or welding generator.
To determine in which way the Remote Hand Control af-
fects the operation of the welding power source or weld-
ing generator, refer to the welding power source or weld-
ing generator circuit diagram and/or instruction Manual.
B. Remote Hand Control Of Two Welding Power
Sources
Remote amperage or voltage control of two welding
power sources from one Remote Hand Control is made
possible through the use of Remote Hand Control hav-
ing two rheostats. These Remote Hand Controls are
identified by a model suffix of -2, and are designed to si-
multaneously control two identical welding power
sources. These Remote Hand Controls have two rheo-
stats coupled on a common control shaft. Rotating the
knob on the Remote Hand Control simultaneously ad-
justs each rheostat in the control to the same value,
thus making possible remote control of two welding
power sources from a single Remote Hand Control.
IMPORTANT: When a Remote Hand Control is used,
refer to the Instruction Manual of the welding power
source or welding generator for additional operational
information.
3-2. CONTACTOR SWITCH
WARNING: ELECTRIC SHOCK can kill.
•
Do not touch live electrical parts
•
Do not touch the weld output terminals when
the contactor is energized.
•
Do not touch electrode and work clamp at the
same time.
IMPORTANT: To use the RHC-14 or RHC-23 contactor
switch, the OUTPUT (CONTACTOR) switch on the
welding power source must be in the Remote position
for proper remote control operation.
The RHC-14 or RHC-23 switch has two positions, ON
and OFF. Placing this switch in the ON position provides
open-circuit voltage. Placing this switch in the OFF posi-
tion stops open-circuit voltage (ocv goes to zero).
SECTION 4 − MAINTENANCE
WARNING: ELECTRIC SHOCK can kill; HOT
SURFACES can cause severe burns.
•
Do not touch live electrical parts.
•
Disconnect plugs from power source before
inspecting or servicing.
•
Allow unit to cool before servicing.
Once a month inspect the Remote Hand Control cord for
breaks in the insulating jacket particularly at the plug
and at the strain relief connector on the Remote Hand
Control base. Repair all breaks with electrical tape, or
replace the cord if necessary.
Daily, rotate the Remote Hand Control knob from the 0
to 100 percent position. This procedure will prevent oxi-
dation from forming on the contacts, which could insu-
late the contacts from the brush, causing the control to
become inoperative. Refer to Table 2-1 for proper cord
conductor size and to Diagrams 5-1 through 5-5 for
proper cord conductor connections.