Introduction, Overview, Features – Rockwell Automation 825-P Modular Protection System for Motors User Manual User Manual
Page 13: Standard protection features, Chapter 1, Overview features, Chapter 1: introduction

Rockwell Automation Publication 825-UM004D-EN-P - November 2012
13
Chapter
1
Introduction
Overview
The 825-P Motor Relay is designed to protect three-phase motors. The basic
relay provides locked rotor, overload, unbalance, and short circuit protection.
Voltage-based and RTD-based protection is available as an option. All relay
models provide monitoring functions.
This manual contains the information for installing, setting, testing, operating,
and maintaining an 825-P. It is not necessary to review the entire manual to
perform specific tasks.
A Quick Start Guide, Publication 825-QS001, is also available. It will help to step
the first-time user through the device commissioning process.
Features
Standard Protection Features
• Thermal Overload (thermal model)
• PTC (positive temperature coefficient) Overtemperature
• Undercurrent (Load Loss)
• Current Imbalance and Phase Loss
• Overcurrent (Load Jam)
• Short Circuit
• Ground Fault (Residual)
• Ground Fault (Zero Sequence)
• Motor Starting/Running
– Protection Inhibit During Start
– Start Motor Timer
– Notching or Jogging Device
– TCU (Thermal Capacity Utilization) Start Inhibit
– Anti-Backspin Timer
– Emergency Start
– Two Speed Protection
– Reduced Voltage Starting (Star-Delta)
– Stall-Speed Switch
• Frequency