STT113 TOWER CRANE OPERATION AND SERVICE MANUAL
6B
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4
III Working principle of controller RTC
Control functional block diagram
The potentiometer RP in interlock operation desk setting phase shift triggering control
voltage of crystal brake tube then could output three circuit signals by the amplifier IC.
The first circuit striking uniphase crystal brake tube of eddy current brake to adjust
the exciting voltage of eddy current. After the second circuit magnify by amplifier
according the voltage polar to decide position and negative turning of motor. The third
circuit striking the six crystal brake tubes by the triphase triggering and make the
motor gain the linear change voltage, then make rotate speed stepless change,
idiographic circuit as follows:
IC
IC
IC
IC
RP
+
V
-
V
RD
RG
RDi
RP
A
B
C
AC48V
RRa
RM
clockwise contactor
Eddy-current voltage output
Voltage feedback
anticlockwise contactor
Three phase adjustable AC voltage