869 MOTOR PROTECTION SYSTEM – INSTRUCTION MANUAL 1–1
869 Motor Protection System
Chapter 1: Introduction
GE
Grid Solutions
Introduction
The Multilin 869 relay is a microprocessor-based unit intended for the management and
primary protection of medium and large sized motors. Base relay models provide thermal
overload and overcurrent protection plus a number of current and voltage based backup
functions.
Overview
The relay features an enhanced thermal model with custom curves, current unbalance
biasing, voltage dependent curves and running and stopped exponential cooling curves.
An optional RTD module allows for the thermal model RTD bias function. Motor start and
supervision functions include thermal inhibit, maximum starting rate, time between starts,
restart delay, acceleration time, and emergency restart. Mechanical jam, current
unbalance elements and VFD application support are also included as basic functions.
Stator differential, sensitive directional power and phase/neutral directional elements are
more advanced features.
These relays contain many innovative features. To meet diverse utility standards and
indus
try requirements, these features have the flexibility to be programmed to meet
specific user needs. This flexibility will naturally make a piece of equipment difficult to
learn. To aid new users in getting basic protection operating quickly, setpoints are set to
typical default values and advanced features are disabled. These settings can be
reprogrammed at any time.
Programming can be accomplished with the front panel keys and display. Due to the
numer
ous settings, this manual method can be somewhat laborious. To simplify
programming and provide a more intuitive interface, setpoints can be entered with a PC
running the EnerVista 8 Setup software provided with the relay. Even with minimal
computer knowledge, this menu-driven software provides easy access to all front panel
functions. Actual values and setpoints can be displayed, altered, stored, and printed. If
settings are stored in a setpoint file, they can be downloaded at any time to the front panel
program port of the relay via a computer cable connected to the serial port of any
personal computer.
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