1.2
SEL-749M Relay Instruction Manual Date Code 20080918
Introduction and Specifications
Features
Optional
Protection Features
The SEL-749M has the following optional protection features:
➤ PTC Overtemperature (49) (positive temperature coefficient
switching thermistor)
➤ Voltage-Based Protection
➢ Undervoltage (27)
➢ Overvoltage (59)
➢ Underpower (37)
➢ Reactive Overpower
➢ Phase Reversal (47)
➢ Power Factor (55)
➤ RTD-Based Protection
Up to twelve (12) RTDs may be monitored when an external
SEL-2600 RTD module is used. There are separate Trip and
Warn settings for each RTD.
Monitoring Features
The SEL-749M has the following monitoring features:
➤ Event Summaries that contain relay ID, date and time, trip
cause, and current/voltage magnitudes. The last five trip causes
are saved in nonvolatile memory.
➤ Event Reports including filtered and raw analog data.
➤ Sequential Events Record (SER).
➤ Motor operating statistics since the last reset:
➢ Running and stopped times
➢ Number of starts and emergency starts
➢ Average and Peak metering values during start and run
periods
➢ Number of various Alarms and Trips
➤ Motor Start Reports, for as long as 60 seconds, for each of the
last 5 starts.
➤ Motor Start Trend data for the past eighteen 30-day intervals.
➤ A complete suite of accurate metering functions.
Communications and
Control
➤ EIA-232, front-panel port
➤ EIA-232, EIA-485, and fiber-optic (receive only) rear-panel
ports
➤ IRIG-B connection
➤ Modbus
®
RTU slave and DeviceNet™ protocols
➤ SEL ASCII, Compressed ASCII, Fast Meter, Fast Operate, Fast
SER, and Fast Message Protocols
➤ Programmable Boolean operators, logic functions, and timers
Courtesy of NationalSwitchgear.com
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