1. INTRODUCTION OVERVIEW
1-1
1. INTRODUCTION
1.1 OVERVIEW
The SR469 Motor Management Relay is a microprocessor based relay designed for the protection and management of medium and
large horsepower motors and driven equipment. The SR469 is equipped with 6 output relays for trips, alarms, and start blocks. Motor
protection, fault diagnostics, power metering, and RTU functions are integrated into one economical drawout package. The single line
diagram of Figure 1-1 illustrates the SR469 functionality using the ANSI (American National Standards Institute) device numbers.
Figure 1-1 SINGLE LINE DIAGRAM
Typical applications include:
• Pumps
• Fans
• Compressors
• Mills
• Shredders
• Extruders
• Debarkers
• Refiners
• Cranes
• Conveyors
• Chillers
• Crushers
• Blowers
Some of the protection highlights are detailed here, a complete list may be found in Table 1-1. Four assignable digital inputs may be
configured for a number of different features including tachometer or generic trip and alarm with a programmable name. The thermal
model incorporates unbalance biasing, RTD feedback, and exponential cooling. In addition to the 15 standard overload curves, there is a
custom curve feature and a curve specifically designed for the starting of high inertia loads, when the acceleration time exceeds the
safe stall time. A second overload curve is provided for two-speed motors. Ground faults or earth leakage as low as 0.25A may be
detected using the Multilin 50:0.025 ground CT. CT inputs for phase differential protection are also provided. The 12 RTD inputs
provided may be individually field programmed for different RTD types. Voltage transformer inputs allow for numerous protection
features based on voltage and power quantities. Four 4-20mA analog inputs may be used for tripping and alarming on any transducer
input such as vibration, pressure, flow, etc.
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