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Block 26
Fan
Consisting of:V1.
Powered directly by block 12 (a
) and
cools the power components.
uxiliary power supply
Block 18
Block 19
Block 20
Block 21
Block 22
Block 23
Block 24
Block 25
Alarm LED
Current potentiometer
Maximum current adjustment
IGBT Thermostat
Galvanic separation
Overvoltage safeguard
Undervoltage safeguard
Power supply LED
Consisting of: D35.
It is switched on by block 17 (alarms) in the event of:
1) Triggering of thermostatic capsule/thermostat on power
transformer.
2) Triggering of thermostatic capsule on secondary diodes.
3) Triggering due to overvoltage.
4) Short circuit at output (electrode holder clamp and earth
cable connected to one another or electrode stuck to
piece being welded).
Consisting of: R75.
This is used to set the reference voltage needed to adjust
the output current: when the potentiometer knob is turned
the cursor voltage varies, thus varying the current from the
minimum to the maximum value.
Consisting of: R70, R71, R72, R73, R74.
Used to adjust the maximum cutting current to be supplied
by the power source.
Consisting of: ST1
When the temperature of the IGBT dissipator reaches a
given temperature the thermostat cuts in, sending an alarm
signal to block 22 (galvanic separation). It is reset
automatically when this alarm condition is no longer
present.
Consisting of: ISO1
The signal arriving from blocks 21 (IGBT thermostat) is
separated galvanically and sent to block 17 (alarms) for
detection of a possible alarm event.
Consisting of: R40, R41, R42, Q3.
If the main supply voltage exceeds the maximum value this
safeguard triggers (a tolerance of approx. ±15% of the
power supply voltage is allowed: outside this range the
safeguard triggers).
Consisting of: R63, R64, U1C, Q8.
If the main supply voltage falls below the minimum
allowed
value this safeguard triggers (a tolerance of approx.
±15% of the power supply voltage is allowed: outside this
range the safeguard triggers).
Consisting of: D34.
Indicates when the power source is correctly powered and
ready for use.
TECNICA 114
