Motor Protection System
Integrated Protection and Control for Medium-Sized AC Motors
Key Benefits
• Enhanced Thermal Model including current unbalance and RTD biasing
• Temperature monitoring with programmable RTD inputs for Stator, Bearing and Ambient temperature protection
• Reduce troubleshooting time and maintenance costs – motor running and learned data, last trip data • Simplify testing - Built-in simulation features
• Cost-effective access to information through standard RS485 serial ports using Modbus RTU
• Field upgradable settings and firmware
• Installation flexibility - Remote display and drawout case options
Applications
• Medium size motors
Features: Protection and Control
• Thermal model biased with RTD and negative sequence current feedback
• Stator winding & bearing overtemperature
• Motor multiple starts
• 8 standard overload curves
• User-defined overload FlexCurve™
• Undercurrent for load loss
• Locked rotor
• Rapid trip/mechanical jam
• Unbalance/single phasing
• Short circuit • Ground fault
• Phase reversal (meter option)
• Variable lock-out time
• Latched main trip relay, alarm relay
• 2 auxiliary relays
• Emergency restart capability
• Pre-trip alarm warnings
Monitoring and Metering
• Current & Thermal Capacity metering
• Data Logger
• Learned & Statistical Data
• Optional voltage, power metering
Inputs and Outputs
• 12 RTDs, programmable
• 5 factory-programmed digital inputs
• 4 output relays
• 1 programmable analog output
EnerVista™ Software
• State-of-the-art software for configuration and commissioning GE Vernova Multilin products
• Document and software archiving toolset to ensure reference material and device utilities are up-to-date • EnerVistaTM Integrator providing easy integration of data in the 269 Plus into new or existing monitoring and control systems
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269 Plus Motor Protection System
Protection and Control
The 269 Plus is a digital relay designed to provide complete and accurate protection for industrial motors and their associated mechanical systems. Protection functions include starting and running. The motor is protected under both acceleration and running conditions.
An alarm or trip may occur based on acceleration time, the number of starts per hour, the time between starts, or motor overload conditions. Overload: One of eight standard overload curves may be programmed based on the manufacturer’s locked rotor time capability. Alternatively, the user may program a custom curve using the built-in FlexCurve™ function. The motor’s service factor value is entered as the overload pickup level.
FlexCurve™: A smooth custom overload curve is created within a selected range using FlexCurve™. This curve can be used to protect motors with different rotor damage and stator damage curves, allowing total motor design capacity with complete protection.
Unbalance (Negative Sequence): Unbalanced supply voltages mean a large increase in the negative sequence current, which can result in greatly increased rotor heating. The relay uses the ratio of the negative to positive sequence currents to bias the thermal model. Unbalance and phase loss protection is also provided. Undercurrent (Minimum Load): The undercurrent function is used to detect a decrease in motor current caused by a decrease in motor load. This is especially useful for indication of conditions such as loss of suction for pumps, loss of airflow for fans, or a broken belt for conveyors. A separate undercurrent alarm level may be set to provide early warning.
Ground Fault: For zero sequence ground fault protection, all three of the motor conductors must pass through a separate ground fault CT. CTs may be selected to detect either high impedance zero sequence ground faults or residual ground faults.
The trip can be instantaneous or time-delayed by up to 20 seconds. A low level of ground fault pickup is desirable for maximum stator winding protection. A 50:0.025 A CT or 5 A CT may be used for ground fault detection.
Rapid Trip/Mechanical Jam: Quick motor shutdown can reduce damage to gears, bearings, and other mechanical parts associated with the drive combination. A current surge will cause the relay assigned to the rapid trip/mechanical jam function to become active. The user may set the pickup level, the trip time delay, and an alarm for early warning.
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