Rockwell Automation 1391ES AC Servo Controller - Manual (Page 24)

Description of Operation
Chapter 4
4-22
Drive Ready
The status of the power supplies and fault conditions are monitored
continuously. If a fault is present, the DRIVE READY LED will not be
illuminated, a fault signal will be present at TB4 and the DROK contact
will be open.
Isolated Current Sensing The Logic Control Boards receive current feedback from the Isolated
Current Sense Board. This circuitry provides the data used for current
limiting and to modify bandwidth.
Integral Circuit Breaker The control logic and power circuitry are protected against overcurrents by
an integral circuit breaker. The DC bus supply and input rectifier utilizes a
three pole magnetic circuit breaker.
Line/DB Contactor The three-phase incoming AC line is opened by the contactor whenever the
Enable signal is removed or a fault occurs. This operation in conjunction
with the shunt regulator reduces the bus voltage when the contactor is
disabled. The Logic Control Board remains energized except when voltage
is removed from the incoming isolation transformer.
Important: The 1391B-ES contains a definite purpose contactor that is not
to be energized/de-energized more than twice an hour on a continuous
basis. The life of the contactor may be reduced considerably if the cycle is
exceeded. Contact your local Allen-Bradley Sales Representative for
additional information.
Power Driver Board The Power Driver Board contains the circuitry needed to switch the power
transistor modules.
A Quad B Board The A Quad B Board changes the resolver signal from a 1326AB or AD
motor into an encoder signal for use by a position controller.
Starting and Stopping
ATTENTION: The Enable control circuitry in the 1391B-ES
includes solid-state components. If hazards due to accidental
contact with moving machinery or unintentional flow of liquid,
gas or solids exist, an additional hardwired stop circuit may be
required. Refer to the codes and standards applicable to your
particular system for specific requirements and additional
information. A device that removes AC input power when a
stop is initiated is an integral part of this controller. Refer to the
following individual stop mode explanations.
!