Rockwell Automation SA3100 AutoMax Distributed Power System - Manual (Page 54)

A-10 AutoMax Distributed Power System Overview
reversing: changing the direction of rotation of the motor armature or rotor. An AC
motor is reversed by swapping two of the three motor leads. A DC motor is reversed
by changing either the polarity of the voltage applied to the field or the armature, but
not both. The reversing function is performed in one of the following ways:
contactor reversing changes the polarity of the voltage applied to a DC motor
armature with switching contactors. The contactors are operated by momentary
push-buttons and/or limit switches to stop the motor and change directions. A zero
speed (anti-plugging) circuit is associated with this system to protect the motor
and control.
field reversing changes the DC polarity applied to the motor shunt field. This type
of reversing can be accomplished with DC-rated contactors or by means of an
electronically controlled solid-state field supply.
manual reversing is reversing the polarity to the DC motor armature by manually
changing the position of a multi-pole switch.
static reversing is reversing the polarity of the motor with no mechanical
switching. This is accomplished electronically. Only regenerative drives are
capable of static reversing.
RISC: Reduced Instruction Set Computer, a type of high-speed microprocessor.
runbase: see operating system.
S2: Reliance name for a single-phase field Power Module.
S2R: Reliance name for a single-phase regenerative field Power Module.
S6: Reliance name for a three-phase armature Power Module.
S6R: Reliance name for a three-phase regenerative armature Power Module.
scan: a single run-through (execution) of an application task.
SCAN_LOOP: a Control Block statement that is used to specify how often a Control
Block task should run.
Scans-Per-Interrupt (SPI%): the name of a register (2001) in the UDC module that
specifies how many scans of the UDC task should elapse between updates of
application registers in the dual port, and optionally, between interrupts to an AutoMax
Processor.
scan time: how often an application task in an AutoMax Processor or UDC module
should execute. The scan time is calculated by multiplying how often the task should
execute (in ticks) by the tick rate (Ticks x Tick Rate).
SCR: see silicon controlled rectifier.
series-wound: DC motor in which field excitation is supplied by a winding connected
in series with the armature.
service factor: how much over the nameplate rating the motor can be run without
overheating. The number is a multiplier of the horsepower, or a percentage of the
horsepower in addition to 100% horsepower.