Output Relays - GE 469 Instruction Manual

469
Motor Management Relay

Output Relays

WARNING
3–20
There are six (6) Form-C output relays (see Specifications on page 2–5 for details).
Five of the six relays are always non-failsafe; 6 SERVICE is always failsafe. As
failsafe, the 6 SERVICE relay is normally energized and de-energizes when called
upon to operate. It also de-energizes when 469 control power is lost and will be in
its operated state. All other 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.
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