Checking The Gate Pulses From Circuit Board 15Ap2 - ESAB Arc 4000i Service Manual

Checking the gate pulses from circuit board 15AP2

WARNING!
During normal operation there is mains voltage on circuit board 15AP2. The machine
must be in soft starting mode when checking the gate pulses, see page 60.
1. Connect an oscilloscope with the probe to TC1 and the screen to TC2.
CAUTION! If you short circuit TC1 and TC2, the gate driver board will be destroyed.
Test points for gate pulses from 15AP2
2. Start the power source and use ESAT to set a current reference.
3. Compare the waveform of the gate pulses with the diagram below.
The waveform shape must be as in the diagram.
4. Measure the pulse
frequency, it must be
27 kHz ±0.5 kHz.
5. Measure the pulse
duration, it must be
39.0 --40.8 % of the cycle
time, measured at a
voltage level of +5 V.
6. Measure the maximum
pulse voltage, it must be in
the range 14 -- 17 V (High
in the diagram above). The
minimum voltage must be
in the range from --9 to
--12.5 V.
7. Connect the oscilloscope with the probe to TD1 and the screen to TD2.
CAUTION! If you short circuit TD1 and TD2, the gate driver board will be destroyed.
8. Repeat the measurements in item 3 to 6 above.
The pulses on terminals TC1, TC2 and TD1, TD2 are in phase with each other.
Pulse frequency and duration are controlled by circuit board 20AP2: rise and fall times are
controlled by gate driver board 15AP2.
cp03f3soft
Gate pulses from 15AP2 to 15Q1 and 15Q2
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S0740 800 191/E080229/P78