THEORY OF OPERATION

E-2

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FIGURE E.3 - Output Rectification, Control and Feedback

 

 

 

 

 

 

 

 

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OUTPUT RECTIFICATION,

 

 

 

to

to

 

 

 

CONTROL AND FEEDBACK

 

 

 

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The AC output from the main transformer sec-

into an isolated drive signal. This isolated signal

 

 

 

 

ondary is rectified through the SCR/ DIODE

drives the transistor module to the optimum level

 

 

bridge. The machine output is controlled through

to obtain the desired machine output current. The

 

 

the

transistor module.

The

output current is

control and power board also generate the gate

 

 

sensed at the shunt, as a low voltage signal, and

firing pulses for the SCR/DIODE bridge. The rec-

 

 

fed back to the control board.

The control board

tified and controlled DC voltage is filtered by the

 

 

compares the commands of the output control

output capacitors and choke and is applied to the

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potentiometer with the shunt feedback signal and

machine's torch and work terminals. The control

the appropriate pulse width modulated (PWM)

board also operates the status board and com-

control signal is sent to the power board.

The

mands the pilot arc circuitry.

 

to Section

to Master

 

power board converts the PWM control signal

 

 

 

 

 

NOTE: Unshaded areas of Block Logic

 

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Diagram are the subject of discussion

 

 

 

 

 

 

 

 

PRO-CUT 60

Page 35
Image 35
Lincoln Electric SVM104-A Output Rectification Control and Feedback, Figure E.3 Output Rectification, Control and Feedback