ESAB Aristotig 405 AC/DC, Service Manual

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A1-5 PRIMARY OVERCURRENT SHUTDOWN
Warning! The circuit and its parts are connected to mains voltage potential.
T1 and T5 monitor the primary current of power transformer T3. When it exceeds a threshold crit-
ical for the MOSFETs on A5, A12 and A4, A11, the monitoring circuit 8 trips the Low side of the
inverter half-bridge A4, A11, and the red LED2 on A1 comes on. A8 and A2 are notified of this
status by the L-active signal to X7-16. Error Code 1 is displayed on the front panel. In the event
of major electro-magnetic interference, the circuit will activate in some cases without any hard-
ware fault, e.g. HF starting directly on the machine frame, etc.
But usually, a primary overcurrent trip is only initiated by a hardware fault, e.g. fault on A5, A12,
A4, A11, AP10, AP11. The machine remains in tripped status until the unit is re-connected to the
mains. Proceed as follows:
Switch off the mains switch Q1. Wait 30 seconds. Switch on mains switch again.
If the error fault is repeated continuously, check the modules in the following order: AP11, AP10,
A5, A12, A4, A11, T3. Also check the electrical connections on the current transformers T1 and
T5.
Cf. section "ERROR CODE 1: PRIMARY OVERCURRENT".
NOTE! T1 and T5 must never be operated with an open-circuit secondary (output). This could de-
stroy it by flashover between the windings.
a1-5.pcx