WTC MedWeld 4000, Руководство оператора

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MedWeld 4000 Overview
1 - 20 Modified: 12/16/08 MedWeld 4000 Operator’s Guide
M-032116 Programs #T03300, #T02300 and #T02400
Firing Card Input Signals
The wires connected to the firing card connector J3 (1L1 and 1L2
without an isolation contactor, or 1L1, 1L2 and 2L2 with an isolation
contactor) originate across the 380/480/600 VAC supply voltage. These
wires carry the zero-crossing logic signal. This signal synchronizes the
weld processor with the supply.
They also provide the voltage-to-frequency logic signal that the weld
processor card uses to measure line voltage.
The current coil generates a voltage signal which is proportional to the
measured current. This signal enters the firing card
via connector J4.
The signal is converted to the current-to-frequency logic signal, which
the weld processor board uses to measure the welder’s current.
The firing card receives a logic-level firing signal through its J2
connector from the weld processor card. This signal is optically coupled
to a high-voltage circuit on the firing card, and controls the SCR wired
through the firing card connector J1.
Firing Card Output Signals
The firing card also outputs a group of logic level signals from the
various connections at the welder’s primary circuit. The weld processor
uses these signals to:
• Find the zero-degree phase angle point on the supply power as a
reference for its phase-angle measurements
• Measure the line voltage, current and power factor
• Adjust the firing phase angle, based on the voltage or current
(depending on the firing mode) and the power factor and
• Check for shorted or misfiring SCR(s).
All of these signals are transmitted over firing card connector J2 and
weld processor card connector J3.
Cascade Firing Board
The MedWeld 4000 can switch multiple contactors with one weld timer,
a firing board and a system of relays. The
Cascade Firing Board (CFB)
implements this capability.
The CFB controls a system of three relays. They switch the gate lead
connections between each firing board and three SCR pairs. This “pass-
through” configuration of relays prevents the possibility of firing more
than one SCR at a time (which can cause catastrophic failure).
The CFB is the same size as a 645 firing board, and uses the same
mounting centers. The interface has four connectors to receive inputs to
the SCR gate leads. Three output signal connectors go to the SCR gate
leads. Three red LEDs indicate activation (if any) of its respective SCR.