EPU

Temperature Monitor for up to 16 PT100/Cu10 Sensors

Universal thermal protection relay for up to 16 PT100 or Cu10 sensors, with cooling control and communication options for supervision and IoT.

Description

The EPU-IoT is a universal thermal protection relay designed to simultaneously supervise up to 16 temperature channels. Its main function is to protect and monitor equipment such as dry-type transformers, motors, bearings, machines and industrial processes. It controls cooling (ON/OFF), issues alarms and performs shutdowns (TRIP) when temperatures exceed predefined limits, ensuring equipment safety and service life.

Through its integration with the MONITRAFO.com platform, the EPU-IoT provides Artificial Intelligence, Machine Learning, Database, Programmable Function, Calculation and Notification, and Maintenance Scheduling tools. These technologies turn the transformer into an intelligent device that can identify changes in behavior within its standard operating cycle and send notifications by email, SMS and apps when abnormal variations occur. This provides a robust tool for effective decision-making.

The EPU-IoT Thermal Protection Relay is a reference for electrical industry professionals and researchers. It meets the technical specifications of the world's leading electric utilities and complies with ABNT NBR 5356-11, IEC 60076-11 and IEEE C57.12.01 requirements governing the use of accessories in temperature monitoring and thermal protection systems for dry-type transformers and/or transformers with epoxy resin cast windings.

Technical data

ANSI / IEEE Function

FUNCTION NUMBER / ACRONYM	FUNCTION NAME / ACRONYM
2	Time-delay Starting or Closing Relay
11	Multifunction Device.
16S	Serial Data Communication Device.
23	Temperature Control Device.
26	Equipment Thermal Device.
30	Annunciator Relay.
49T	Transformer Thermal Relay.
74	Alarm Relay.
77	Telemetering Device.
94	Digital Output for TRIP.
HMI	Human-machine Interface.
TCM	Trip Circuit Monitoring Scheme.

Dimensions and Power Supply

• Compact device: 98 x 98 x 94 mm;

• Universal 24–275 VDC / VAC power supply;

Human-machine Interface (HMI)

• 4 navigation keys;

• 9 or 10 front-panel LEDs for event indication (see order);

• Intuitive menus for viewing and parameter configuration;

Communication Protocols

• Modbus RTU

• DNP3

• DNP3 over TCP/IP on IP networks

• Modbus TCP/IP

• MQTT

Communication Ports

• Integrated WIFI modem
o 802.11 b/g/n/e/i standards;
o WPA/WPA2/WPA-Enterprise security protocol;
o AES/RSA/ECC/SHA encryption;
o Data rate up to 150 Mbps;
o Built-in 3 dBi antenna (decibels relative to isotropic);
o Transmit power up to 21 dBm (decibels relative to one milliwatt);

• Bluetooth
o Class 2 – 2.5 mW (4 dBm);
o FIPS encryption;
o Version 4.2 BR / EDR and BLE (Low Energy);

• USB
o Version 2.0;
o Transfer rate: 480 Mbps;
o Type-C connector.

• RS-485
o ANSI/TIA/EIA-485-A standard;
o Max. 32 devices;
o Half duplex;
o Multipoint;
o Max. distance: 1,200 meters;
o 2 metallic wires;
o Automatic speed from 2,400 to 57,600 bps.

• RJ-45 TCP/IP
o TIA/EIA-568-B standard;
o ISO/IEC 11801 standard;
o 8 pins;
o 100-ohm impedance;
o 10BASE-T, 100BASE-TX standard.
o Max. distance, Cat 5e/6/6a/7: Up to 100 meters for Ethernet.
o Max. distance, Cat 8: Up to 30 meters for high-speed Ethernet.
o Return loss: -18 dB minimum @ 1–30 MHz, -16 dB minimum @ 30–60 MHz, -12 dB minimum @ 60–90 MHz;
o Common-mode rejection ratio: -30 dB minimum @ 1–100 MHz;
o Isolation: 1.5 kV / 60 Hz / 1 minute.

Measurement Input

• Up to 16 temperature measurement inputs for PT100 sensors, 100 Ω at 0°C (EN60751 – DIN43760), or Cu10 temperature sensors, 10 Ω at 25°C;

• Accuracy: 0.5% (FS);

Digital Relay Outputs

• 01 relay (NO/NC) rated at 10 amperes for temperature alarm

• Up to 02 relays (NO/NC) rated at 10 amperes for FAN (cooling);

• 01 relay (NO/NC) rated at 10 amperes for TRIP (shutdown), with programmable actuation delay;

• 01 relay (NO/NC) rated at 10 amperes for FAULT;

Analog Outputs

• Supports up to 05 (five) analog outputs (active, 15 VDC) with range options of 0 to 1 mA, 0 to 5 mA, 0 to 10 mA, 0 to 20 mA and 4 to 20 mA;

Type Tests Passed

• Applied voltage (IEC 60255-5): 2 kV / 60 Hz / 1 min. (to ground);
• Impulse voltage (IEC 60255-5): 1.2/50 µs / 5 kV / 3 negative and 3 positive / 5-second interval;
• Electrostatic discharge (IEC 60255-22-2): Air discharge = 8 kV / Contact discharge = 6 kV;
• Radiated electromagnetic disturbance immunity (IEC61000-4-3): 80 to 1000 MHz / 10
V/m;
• Electrical fast transient immunity (IEC60255-22-4): Power supply/inputs/outputs
= 4 kV / common mode 2 kV;
• Surge immunity (IEC 60255-22-5): Phase/neutral 1 kV, 5 per polarity (±) – phase-to-ground/neutral-to-ground 2 kV, 5 per polarity (±);
• Conducted electromagnetic disturbance immunity (IEC61000-4-6): 0.15 to 80 MHz /
10 V/m;
• Climatic test (IEC60068-21-14): -40°C to +85°C / 72 hours;
• Vibration endurance (IEC 60255-21-1): 3 axes / 10 to 150 Hz / 2 G / 160 min/axis;
• Vibration response (IEC60255-21-1): 3 axes / 0.075 mm at 10 to 58 Hz / 1 G from 58 to 150 Hz
/ 8 min/axis.