APPENDIX A: TECHNICAL SPECIFICATIONS
PHASEMASTER™ 6 DIRECT ENERGY WELDING CONTROL
A-4
990-083
Polarity Selection
Polarity Selection sets the initial direction of the weld current flow through the workpiece. This is normally
not important in full cycle AC welding since the weld current reverses direction every half-cycle. This
feature is
useful for half-cycle welding applications
that are sensitive to the direction of weld current flow
because of dissimilar materials and/or materials with thickness ratios which are greater than 4 to 1. In these
cases, place the Negative Electrode against the thinner or more resistive material. The user can select
Positive (+), Negative (-) or Alternate Polarity. Alternate Polarity means that the polarity of the first half
cycle of output changes with each weld. Alternate Polarity can be used to prevent Hypersil weld
transformers from saturating. Unitek Peco Weld Transformers do not use Hypersil cores.
Power Factor Correction
Microprocessor control automatically ensures that the actual welding current percentage is within ±3% of
the value selected, regardless of the power factor of the load. Without this feature, the welding current
would change with the position of the cables and/or whenever a magnetic workpiece was placed between
the electrodes.
Head Type
The PM6 can be used with a Manual, user actuated, or Air Actuated Weld Head. Air Actuation means that
the PM6 will provide 24 or 115 VAC output which can be used to control an air valve (solenoid) on an Air
Actuated Weld Head. The Front Panel MANUAL/AIR HEAD TYPE INDICATOR indicates whether a
Unitek Peco Air Head is connected to the Valve Driver Connector located on the rear panel. The user can
indicate the presence of a user supplied air head by jumpering Pin 4 to Pin 2 on the Valve Driver Connector.
Refer to Valve Driver Connector. If Pin 4 is not connected to Pin 2, then the PM6 assumes that a Manual
Head is being used. The PM6 determines whether it is connected to an Air or Manual Head when power is
first applied to it and displays the result of this analysis on the HEAD TYPE Indicator located on its front
panel.
Valve Driver
The output of the valve driver circuit is 15 volt-amps at 115 or 24 volts AC. This circuit is fused, together
with the control board, by Fuse F1 located on the rear panel. The connector is wired so that both 115 and
24-volt AC are available.
