GE Multilin 469, Instruction Manual

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CHAPTER 3: INSTALLATION
469 MOTOR MANAGEMENT RELAY – INSTRUCTION MANUAL 3–23
relays, being non-failsafe, will normally be de-energized and energize when called upon to
operate. When the 469 control power is lost, these relays are de-energized and in their
non-operated state. Shorting bars in the drawout case ensure that no trip or alarm occurs
when the 469 is drawn out. However, the 6 SERVICE output will indicate that the 469 has
been drawn out. Each output relay has an LED indicator on the front panel that turns on
when the associated relay is in the operated state.
Relay contacts must be considered unsafe to touch when the 469 is energized! If the
output relay contacts are required for low voltage accessible applications, it is the
customer's responsibility to ensure proper insulation levels.
• 1 TRIP: The trip relay should be wired to take the motor off line when conditions
warrant. For a breaker application, the normally-open 1 TRIP contact should be wired
in series with the Breaker trip coil. For contactor applications, the normally-closed
1 TRIP contact should be wired in series with the contactor coil.
Supervision of a breaker trip coil requires that the supervision circuit be in parallel with
the 1 TRIP relay output contacts. With this connection made, the supervision input
circuits place an impedance across the contacts that draws a 2 mA current (for an
external supply voltage from 30 to 250 V DC) through the breaker trip coil. The
supervision circuits respond to a loss of this trickle current as a failure condition.
Circuit breakers equipped with standard control circuits have a breaker auxiliary
contact permitting the trip coil to be energized only when the breaker is closed. When
these contacts are open, as detected by the Starter Status Digital Input monitoring
breaker auxiliary contacts, trip coil supervision circuit is automatically disabled. This
logic allows the trip circuit to be monitored only when the breaker is closed.
• 2 AUXILIARY, 3 AUXILIARY: The auxiliary relays may be programmed for trip echo,
alarm echo, trip backup, alarm differentiation, control circuitry, and numerous other
functions. They should be wired as configuration warrants.
• 4 ALARM: The alarm relay should connect to the appropriate annunciator or
monitoring device.
• 5 BLOCK START: This relay should be wired in series with the start pushbutton in either
a breaker or contactor configuration to prevent motor starting. When a trip has not
been reset on a breaker, the block start relay prevents a start attempt that would
result in an immediate trip. Any lockout functions are also directed to the block start
relay.
• 6 SERVICE: The service relay operates if any of the 469 diagnostics detect an internal
failure or on loss of control power. This output may be monitored with an annunciator,
PLC or DCS. If it is deemed that a motor is more important than a process, the service
relay normally-closed contact may also be wired in parallel with the trip relay on a
breaker application or the normally-open contact may be wired in series with the trip
relay on a contactor application. This will provide failsafe operation of the motor; that
is, the motor will be tripped off line in the event that the 469 is not protecting it. If
however, the process is critical, annunciation of such a failure will allow the operator
or the operation computer to either continue, or do a sequenced shutdown. See the
following figure for details.