Soft Starting; Checking The Gate Pulses From Circuit Board 20Ap1 - ESAB Arc 4000i Service Manual

Soft starting

We recommend soft starting of the machine after replacing control circuit board 20AP1,
relay board 20AP2 or circuit boards or components in the power module. This supplies the
power module with a low DC voltage in order to avoid injury to persons or damage to
components.
It is a good idea to use soft starting when fault tracing in the power module.
Special equipment
To soft--start the machine you need soft--starting tool SST 2 and the ESAT service kit, this is
described on page 56.
Changing wire connections prior to soft starting
1. Disconnect wires 261, 262 and 263 from terminal
block A on circuit board 15AP1.
2. Unplug contact 2XS2 from 15AP1.
3. Insulate the wires that have been removed
from each other and from all other parts.
4. Disconnect the HF starting unit by removing fuse
2FU5 from transformer 2TC2: see the wiring
diagram on page 14.
5. Connect a PC with ESAT to the power source.
6. Connect the SST 2 to 20AP1 and 15AP1 as shown below. Connector C must only be
connected if there is an interuption in the temperature monitoring circuits.
SST 2 connected to 20AP1 and 15AP1

Checking the gate pulses from circuit board 20AP1

Note! The machine must be in soft starting mode when checking the gate pulses.
1. Start the power source and use ESAT to set a current reference.
cp03f3soft
Disconnections prior to soft starting
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S0740 800 191/E080229/P78