GE Industrial Solutions EntelliPro ES - Manual (Page 113)

CHAPTER 3: MOTOR PR OTECTION
EP OS MOTOR MANAGEMENT SY STEM – INSTRUCTION MANUAL 3.1
GE Industrial Solutions
EPOS Motor Management System
Chapter 3: Motor Protection
The EntelliPro ES provides the following protection functions:
Thermal overload with n-times auto-reset
Phase loss
Phase unbalance
Ground fault
Overcurrent and stalled rotor protection
Undercurrent
Thermistor
3.1 Thermal Overload
Thermal overload is the primary protective function of the EntelliPro ES. The heating and cooling thermal model
function reflects the stator and rotor heating and cooling from overload, phase loss, and unbalance conditions.
The motor heating rate is gauged by measuring the average current of the phases. The accumulated motor heating
value is calculated continuously. When the motor is in overload state, the motor temperature and the accumulated
motor heating value will rise. A trip occurs when the accumulated motor heating value reaches 100%.
When the motor is stopped and is cooling to an ambient temperature, the accumulated motor heating value decays
to zero according to the selected cooling settings.
The thermal model consists of five key elements:
Unbalance current biasing that accounts for negative-sequence heating.
Hot/cold biasing that accounts for normal temperature rise.
Overload curves in compliance with IEC 60947-4-1.
Cooling rate that accounts for heat dissipation.
Thermal protection n-times reset .
Each of these categories is described in the following sections.
NOTE: If the EntelliPro ES is configured as an ATEX device, the thermal overload protection is enabled and set to
generate a fault . It cannot be modified to generate a warning.