Multilin 469 Motor Management Relay ... - GE Digital Energy

5.3.4 Communications Control
CHAPTER 5: SETTINGS
Enter the nominal system frequency here. These settings allow the 469 to determine the
internal sampling rate for maximum accuracy.
The 469 may be used on variable frequency drives when the NOMINAL SYSTEM FREQUENCY
is set to “Variable”. All of the elements function in the same manner with the following
exceptions: the ratio of negative to positive-sequence current is calculated from 0 to 30%,
not 40%, and the voltage and power elements work properly if the voltage waveform is
approximately sinusoidal. An unfiltered voltage waveform from a pulse width modulated
drive cannot be measured accurately; however, the current waveform is approximately
sinusoidal and can be measured accurately. All current elements will function properly.
Note, however, that undervoltage and underfrequency elements will not work
instantaneously using variable frequency. If “Variable” is chosen, the filtering algorithm
increases the trip and alarm times by up to 270 ms when the level is close to the threshold.
If the level exceeds the threshold by a significant amount, trip and alarm times will
decrease until they match the programmed delay. The exceptions to this increased time
are the short circuit, ground fault, and differential elements which will trip as per
specification.
If the sequence of phase rotation for a given plant is ACB rather than the standard ABC, the
SYSTEM PHASE SEQUENCE settings may be used to accommodate this. This settings allows
the 469 to properly calculate phase reversal, negative sequence, and power quantities. The
SPEED2 PHASE SEQUENCE can be programmed to accommodate the reversed motor
rotation at Speed2 and is seen only if two-speed motor protection is enabled.
PATH: SETTINGS S2 SYSTEM SETUP SERIAL COMM. CONTROL
SERIAL
COMM. []
MESSAGE
SERIAL COMMUNICA-
TION
ASSIGN START CON-
TROL
Range: On, Off
Range: Auxiliary2, Aux2 & Aux3,
Auxiliary3
If enabled, motor starting and stopping is possible via any of the three 469 communication
ports. Refer to GE publication GEK-106491: 469 Communications Guide for command
formats. When a stop command is issued, the 1 TRIP relay is activated for 1 second to
complete the trip coil circuit for a breaker application or break the contact coil circuit for a
contactor application. When a start command is issued, the auxiliary relay assigned for
starting control is activated for 1 second to complete the close coil circuit for a breaker
application or complete the start control circuit for a contactor application. A contactor
sealing contact would be used to maintain the circuit.
For details on issuing a start or stop command via communications, refer to GE publication
GEK-106491: 469 Communications Guide.
5–20 469 MOTOR MANAGEMENT RELAY – INSTRUCTION MANUAL