ALSTOM 3EST125-975 DCC2382A

The ALSTOM 3EST125-975 is a thermistor-based thermal protection relay designed for continuous winding temperature monitoring of large rotating electrical machines, including generators and motors. The DCC2382A is the associated Digital Control Card (DCC) module that interfaces with the relay to provide signal conditioning, alarm processing, and trip output logic. This system is deployed in power generation plants, hydroelectric stations, and heavy industrial facilities where precise thermal protection of stator and rotor windings is mandatory.

Category: Others

Description

Technical Specifications

Parameter	Value
Manufacturer	ALSTOM (now part of GE Grid Solutions)
Model Number	3EST125-975
Associated Card	DCC2382A
Input Type	6-channel PT100 / PT1000 RTD inputs
Measurement Range	-50°C to +250°C
Accuracy	±0.5°C (at 0°C to 150°C)
Resolution	0.1°C
Supply Voltage	24 V DC (nominal), range 18–30 V DC
Output Contacts	4 changeover relays (SPDT), rated 250 V AC / 5 A
Communication	RS-485 Modbus RTU, optional Ethernet
Dimensions (DCC2382A)	160 mm × 90 mm × 35 mm (approximate, DIN rail mountable)
Operating Temperature	-20°C to +60°C
Protection Class	IP20 (front panel), IP40 (with enclosure)
Standards Compliance	IEC 60034-11, IEC 60255, IEEE C37.95

Functional Features

Continuous temperature monitoring of up to 6 winding zones simultaneously
Programmable alarm thresholds (Warning / Alarm / Trip) per zone
Trip logic with configurable delay times (0.5 s to 60 s)
Cold junction compensation for RTD accuracy
Self-diagnostic function with LED status indicators
Modbus RTU protocol for integration with DCS/SCADA systems
Fail-safe design — loss of power or signal triggers a trip output

Performance Parameters

Parameter	Specification
Sampling Rate	100 ms per channel (cyclic)
Trip Response Time	< 200 ms (from threshold exceedance)
Insulation Resistance	> 100 MΩ at 500 V DC
Dielectric Strength	2000 V AC, 1 minute
MTBF	> 100,000 hours
EMC Compliance	IEC 61000-4-2 (ESD), IEC 61000-4-3 (RF), IEC 61000-4-4 (EFT)

Material Composition

Component	Material
Housing (DCC2382A)	FR-4 PCB, fiberglass-reinforced epoxy
Connector Blocks	Phosphor bronze with gold plating
Enclosure (Relay Unit)	Polycarbonate / ABS blend, UL94 V-0 rated
RTD Input Terminals	Nickel-plated copper
Relay Contacts	Silver-cadmium oxide (AgCdO)

Structural Features

DIN rail mounting (35 mm top-hat rail, TS35)
Front-accessible terminal blocks for RTD wiring
Modular card-based architecture — DCC2382A plugs into the main relay chassis
LED indicators: Power, Alarm, Trip, Fault per channel
Screw-clamp terminal connections rated for 2.5 mm² to 4 mm² wire

Working Principle

The 3EST125-975 uses 4-wire RTD measurement to eliminate lead resistance errors. Each of the 6 PT100/PT1000 sensors is excited with a constant current source, and the resulting voltage drop is digitized by a 24-bit ADC on the DCC2382A. The digital signal is compared against user-programmed temperature thresholds. When a threshold is exceeded for the configured duration, the corresponding changeover relay activates, sending a trip signal to the generator breaker or initiating an alarm. The Modbus interface transmits real-time temperature data and alarm status to the plant SCADA.

Advantages & Highlights

6-channel simultaneous monitoring in a single compact unit
High accuracy ±0.5°C suitable for Class H insulation systems
Fully programmable via front panel or Modbus
Redundant trip outputs — 4 independent relay contacts
Proven field record in ALSTOM/GE hydro and thermal power plants worldwide
Hot-swappable DCC card — DCC2382A can be replaced without powering down the entire relay

Applicable Industries

Industry	Application
Power Generation (Hydro)	Generator stator winding thermal protection
Power Generation (Thermal/Gas)	Turbine generator monitoring
Oil & Gas	Large motor and generator protection
Mining	Hoist motor thermal monitoring
Pulp & Paper	Large drive motor protection

Model Series

Model	Channels	Notes
3EST125-975	6	Standard version
3EST125-976	8	Extended channel version
3EST124-xxx	4	Reduced channel version

Installation Requirements

Mount on DIN rail TS35 in a control cabinet with adequate ventilation
Maintain minimum 50 mm clearance above and below the unit
RTD cables must be shielded twisted pair, maximum length 200 m
Ground the cable shield at one end only (control room end)
Supply voltage must be 24 V DC ±15%, ripple < 5%

Usage Precautions

Never exceed 250°C on any RTD input — permanent sensor damage occurs
Verify RTD type (PT100 vs PT1000) matches the configuration before commissioning
Perform calibration check every 12 months using a precision temperature simulator
Do not operate with the front cover removed — high voltage present on terminal blocks
Ensure Modbus address is unique on the RS-485 bus (default address: 1)

Reviews (0)

Reviews

There are no reviews yet.

Be the first to review “ALSTOM 3EST125-975 DCC2382A”

Shipping and Delivery

MAECENAS IACULIS

Vestibulum curae torquent diam diam commodo parturient penatibus nunc dui adipiscing convallis bulum parturient suspendisse parturient a.Parturient in parturient scelerisque nibh lectus quam a natoque adipiscing a vestibulum hendrerit et pharetra fames nunc natoque dui.

ADIPISCING CONVALLIS BULUM

Vestibulum penatibus nunc dui adipiscing convallis bulum parturient suspendisse.
Abitur parturient praesent lectus quam a natoque adipiscing a vestibulum hendre.
Diam parturient dictumst parturient scelerisque nibh lectus.

Scelerisque adipiscing bibendum sem vestibulum et in a a a purus lectus faucibus lobortis tincidunt purus lectus nisl class eros.Condimentum a et ullamcorper dictumst mus et tristique elementum nam inceptos hac parturient scelerisque vestibulum amet elit ut volutpat.