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APPENDIX A: TECHNICAL SPECIFICATIONS
875DP/500DP/500HV DUAL PULSE
RESISTANCE WELDING POWER SUPPLIES
990-290
A-15
These power supplies issue three alarms. All alarms terminate or inhibit the welding sequence. To clear an
alarm, press [RUN] or toggle the remote process inhibit line. Alarm conditions are processed in a priority
order corresponding to the following list:
1 ALARM SCR: The output SCR, which discharges the capacitor bank into the pulse transformer, may be
defective.
2 ALARM EMERGENCY STOP: An emergency stop signal was received via the CONTROL SIGNALS
connector.
3 ALARM FIRING SWITCH: The force firing switch in the weld head either did not stay closed during
the weld sequence, or did not close within 10 seconds after the 1-level footswitch or the second level of
a 2-level footswitch closed.
Air Valve Driver
The air valve driver provides power to control the solenoid of an air actuated weld head. The power
supplies can sequentially operate two separate air actuated weld heads using two receptacles on the rear
panel, AIR VALVE DRIVER 1 and AIR VALVE DRIVER 2.
Air Valve Driver 1
The output from the AIR VALVE DRIVER 1 receptacle is 12 volt-amps at 24 or 115 volts AC. This
circuit is fused, together with the control printed circuit board, by Fuse F1 located on the control printed
circuit board. The receptacle is wired so that either 115 or 24 volts are available. Air Valve Driver 1 is
configured through the options menu, WELD HEAD TYPE, and selecting either AIR or AUTO.