ABB ACH550 User Manual page 31

E-Bypass Configurations for ACH550 Drives
Bypass Override (Override 2)
The Bypass Override (Override 2) input can be connected to an external contact that
is closed to select the Bypass Override mode. See "Bypass Override Mode" on page
26 for a description of this mode.
Relay Contact Outputs
Bypass Fault
The Bypass Fault relay is energized during normal operation. The Bypass Fault
relay is de-energized when a bypass fault has occurred or when the bypass motor
overload/underload protection has tripped.
System Run
The System Run relay is energized when the E-Bypass System is running. The
System Run relay provides an output when the motor is running whether powered by
the ACH550 drive or the bypass.
Separate Drive Run and Bypass Run contacts can be created by using the common
(C) contact of the System Run relay and connecting the normally open (NO) contact
of the System Run relay to the common (C) contact of the Mode / Override relay. To
do this the Mode / Override relay must be configured for Mode relay operation. See
"Check E-Bypass Jumpers, Switches and Pots" on page 19. The normally closed
(NC) contact of the Mode relay becomes the Drive Run contact and the normally
open (NO) contact of the Mode relay becomes the Bypass Run contact This
configuration provides outputs that are closed when the motor is running. See "The
Bypass Application Macro" starting on page 32.
System Started
The System Started relay is energized when the E-Bypass system is started. Three
conditions must be met in order for the relay to energize.
• A Start command must be present,
• The Safety Interlock input contact must be closed and
• There can be no fault present in the system.
The Start command can come from the bypass control board terminal block, the
ACH550 keypad, the bypass keypad, or serial communications, depending on the
operational mode selected. The System Started relay is ideal for use in damper
actuator circuits, opening the dampers only under those conditions where the
system is preparing to run the motor. Closing the dampers if the safeties open, the
system faults, or when a Stop command is issued.
Mode/Override
The Mode / Override relay is a configurable relay. The function of the relay is
selectable between Mode and Override operation. If the Mode / Override relay is
configured for Mode operation (Default), the relay is energized when the Bypass
mode is selected and de-energized when the Drive mode is selected. If the Mode /
Override relay is configured for Override operation, the relay is energized when the
Override mode is selected and de-energized in all other modes. See "Check
E-Bypass Jumpers, Switches and Pots" on page 19.
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Start-up