Tweco ULTRAFEED VAF-4, Руководство по обслуживанию

Страница: 67 / 120

ULTRAFEED VAF-4
Manual 0-5332 OPERATION 4-37
4.23 PTC (Positive Temperature Coefficient) Protection of Power Source Contactor
Control Output
The Power Source Contactor control circuit on the Ultrafeed VAF-4 provides a relay closure to the power source through
pins A and B of the 19 pin control cable. This allows the welding wire to become electrically ‘HOT’ when the gun switch
trigger on the welding gun is pulled. If this relay closure is NOT provided for any reason, the welding wire WILL NOT
be electrically ‘HOT’. The wire will feed, but there will be NO arc when the wire touches the work.
The Ultrafeed VAF-4 has a thermal, self reset protection device in the A-B contactor circuit to protect the circuitry
against a fault or overload condition. This protection device will only allow a maximum steady state current in the
range of 180 to 450 milliamps (dependent on ambient temperature) to flow through pins A and B of the 19 pin control
cable to the A-B contactor circuit on the Ultrafeed VAF-4.
If this acceptable current range is exceeded for any reason, the self-reset protection circuit located on the motor
control PCB will be activated effectively disabling the A-B contactor circuit. Once the fault or overload condition has
been corrected and the current has returned to an acceptable level, the protection device will automatically reset and
normal operation can resume.
NOTE
The protection circuit will remain activated (there will be NO arc when the wire touches the work) as long
as the acceptable current range is exceeded.
4.24 Ground Fault Operation
The Ultrafeed VAF-4 has been equipped with a ground fault protection circuit. This protection circuit is activated when-
ever excessive current flow in the protective earth ground is detected. If the ground fault protection circuit is activated,
the yellow FAULT indicator on the front of the feeder will flash at a rate of approximately 0.5 second on, 0.5 second off.
Error code ERR 01 will be displayed. When a ground fault occurs, the feeder will immediately shut down the feeder,
gas valve, and power source contactor. Once the ground fault protection circuit has been set, the wire feeder will not
respond to a gun switch closure until the power is reset by turning the feeder off and back on.
NOTE
Before resetting power to the wire feeder after a ground fault occurrence, determine what caused the ground
fault and correct the problem before attempting to weld again.
4.25 Electronic Motor Protection
The Ultrafeed VAF-4 utilizes an electronic protection circuit to protect the motor against overcurrent caused by exces-
sive load on the motor. This protection will normally trip if the motor stays in current limit for about 10 seconds and
during this 10 second period the fault light will flash at a rate of approximately 0.3 second on, 0.3 second off. Once
this 10 second timing period completes, the protection circuit will trip which will cause the FAULT indicator LED to
light continuously, error code ERR 03 or ERR 04 (refer to Section 5.01 Error Code and Remedies) will be displayed
and the Wirefeeder will shutdown the wire feeding gas valve and power source ,and can't be adjusted. In order to reset
this condition, the power to the Wirefeeder must be turned OFF then ON to reset and clear Error Code from display.
NOTE
Should this condition occur, check the wire feeding path, and make sure that there is not any restrictions
or binding on the wire, and that the feedrolls aren’t locked by some obstruction.