Worldwel Longrun 25CA, Руководство по эксплуатации

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By this, in the SCR1 GATE flows a pulse current in the circuit where
the SCR1 point and authorizes the power voltage by the motor. The
SCR1 points only once which the pulse current flows in the kate
between anode A and cathode K.
The SCR1 point-phase can be adjusted by the means of change
the transistor TR and impedance Z.
Transistor TR' impedance Z is proportional to the ARC voltage and
the difference in pressure (Val-Vml) of motor's weight power and it
changes due to base current.
Therefore when (Val-Vml) increase, the base current increases, and
with that effect Z reduces to allow SCR1 point-phase to move
forward. If (Val-Vml) decreases, the movement reverses and the
point phase will step backwards.
2) Controlling ARC voltage
By some reason, the ARC voltage can be set higher than the actual
SET when the ARC voltage is in steady SET by means of WVC1.
Then the (Val-Vml) is the only figure increasing so the base current
of the transistor increase along with Z decreasing, thus SCR1's
point-phase moving forward.
By this mean, the voltage in authorized motor is increased hence
the wire transmitting voltage is increased as well which makes the
ARC voltage to decrease and recovering the SET value. Also, the
ARC voltage comes to default even if the ARC voltage goes down
than SET value by means of reverse movement.
The ARC voltage is always set to the SET value due to sensitive re
reaction of wire transmitting velocity and the slightest change of the
ARC voltage.
3) Wire slow down circuit
For easier welding start-up, the wire SLOW DOWN circuit is the
circuit to slow down the transmission of wire due to the ARC. Until
the ARC generation, there is the slow version of transmission by the
wire inching velocity.