Theory of operation, Wire drive motor and feedback, E-4 wire-matic 255 – Lincoln Electric WIRE-MATIC 255 SVM 119-A Manuel d'utilisation
Page 47
E-4
THEORY OF OPERATION
E-4
WIRE-MATIC 255
WIRE DRIVE MOTOR AND
FEEDBACK
The wire drive motor is controlled by the control board.
A motor speed feedback signal is generated at the
motor tach and sent to the control board. The control
board compares this feedback signal with the com-
mands set forth by the Wire Speed Control poten-
tiometer and sends the appropriate armature voltage
to the wire drive motor. The drive motor speed is thus
controlled which in turn regulates the electrode wire
feed speed through the gun.
Figure E.5 - Wire Drive Motor and Feedback.
WIRE DRIVE MOTOR AND FEEDBACK
LINE
SWITCH
MAIN
TRANSFORMER
RECONNECT
FAN
MOTORS
SCR
RECTIFIER
C
A
P
A
C
I
T
O
R
S
SHUNT
CHOKE
WIRE
DRIVE
MOTOR
TACH
POSITIVE
TERMINAL
NEGATIVE
TERMINAL
GAS
SOLENOID
WIRE
SPEED
ARC
VOLTAGE
CONTROL BOARD
FEEDBACK
GUN TRIGGER AND THUMB SWITCH
F
E
E
D
B
A
C
K
G
A
T
E
I
G
N
S
A
L
NOTE: Unshaded areas of Block Logic
Diagram are the subject of discussion