ESAB AristoFeed 30 4 Series Service Manual page 13

Valid for serial no. 038- , 105- , 136- , 214- , 233- , 249- , 445- xxx- xxxx
Wire feeders with serial number prior to 136--xxx--xxx, with software version
prior to 2.81A: The current limit is 15 A on starting. After one second, this is
reduced to 8 A in the AristoFeed 30 and 9 A in the AristoFeed 48.
Wire feeders from serial number 136--xxx--xxx (from software version 2.81A)
AristoFeed 30: The current limit is 15 A on starting. After one second, this is
reduced to 13 A.
AristoFeed 48: The current limit is 18 A on starting and remains at 18 A.
The current limit is related to the pulse peak current.
If the current exceeds the current limit, IC14:2 interrupts the gate pulse to Q4.
The current falls, and Q4 conducts on the next gate pulse, which is again
interrupted if the current is still too high. This sequence continues until the
motor current has fallen below the current limit.
Speed monitoring
Wire feed speed is monitored by the microprocessor on the circuit board.
Wire feed is stopped if the feed speed deviates from the set speed by more
than 1.5 m/min for more than 5.1 seconds. The MMC panel displays fault
code 11.
Braking
Capacitor C67 is charged via diode D31 when the motor starts. Zener diodes
D33 and D34 limit the voltage to 15 V.
When optocoupler IC11 is energised, its output transistor conducts and
connects capacitor C67 to the gate of transistor Q2, which conducts and
short--circuits the motor supply via dynamic braking resistors R71 and R79.
The resistors limit the current to about 20 A.
Schematic diagram of the motor drive stage
S0740 800 132/E060707/P40
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cmel1d_13ap1a