EATON EMT6-KDB Motor Protection Relay

(Order No.: 269471)

Product Type: Thermistor (PTC) Motor Protection Relay, Ex Explosion-proof, Dual Sensor Circuit

Eaton Moeller EMT6 series for PTC thermistor temperature monitoring of motor windings.

K = ATEX explosion-proof certification; DB = Dual sensor input circuit

✅ Model Code Explanation

EMT6: Series, PTC thermistor motor protection relay

K: ATEX certified, suitable for Ex e explosion-proof motor applications

DB: Two independent PTC sensor input circuits (simultaneously monitor 2 temperature points, e.g. stator + bearing, or pre-alarm + trip)

Order code: 269471

✅ Key Features

Dual PTC circuit monitoring, two sensor channels evaluated independently to support pre-warning and protection logic
Sensor wire break and short-circuit detection (unique to K variants: detects not only wire breakage but also short circuits of sensor cables)
Zero-voltage safety protection (undervoltage lockout): the relay will not auto-reset after tripping due to power loss; configurable via DIP switch
Resettable modes: local manual reset / remote reset
Front panel Test/Reset button for commissioning to simulate over-temperature faults
Status LEDs: power indication, fault indication
SIL 1 safety level (DIN EN 50495), suitable for temperature protection of explosion-proof equipment

✅ Electrical Specifications

Supply voltage: 24～240V AC/DC wide range

Auxiliary contact: 1NO + 1NC (changeover contact), rated thermal current 6A

Sensor type: PTC thermistor (130℃ / 150℃ PTC embedded in motor windings)

Thresholds: Over-temperature trip >1330Ω; reset <550Ω; sensor short-circuit fault <50Ω

Mounting: DIN rail snap-on mounting, width 22.5mm

Terminals: Screw terminals, tightening torque 1.2Nm

Enclosure protection: IP20 (for cabinet installation only)

Ambient temperature: Operating -25℃ ~ +60℃ (max. +45℃ for tightly sealed cabinets)

Standards: IEC/EN 60947-8, ATEX, CE, UL, CCC certification

✅ Applications

Winding temperature protection for Ex-e increased safety explosion-proof motors (primary use case for K models)

Temperature protection for motors, gearboxes, pumps and fans via PTC thermistors

Dual-point temperature monitoring: e.g. one channel for winding over-temperature trip, one channel for bearing pre-alarm

Thermal protection for equipment in chemical, pharmaceutical, coal and other explosion hazardous areas

✅ Comparison of Related Series Models

Model	Order No.	No. of Circuits
EMT6-K	269470	Single
EMT6-KDB	269471	Dual
EMT6-DB	66167	Dual
EMT6-DBK	66168	Dual

✅ Troubleshooting Guide

No LED on power-up: Check supply voltage 24~240V AC/DC
Fault LED steady ON:

PTC over-temperature (resistance >1330Ω)

Sensor circuit wire break

Sensor cable short-circuit (KDB exclusive detection function)

Cannot reset after trip: Zero-voltage lockout is activated; power cycle or disable undervoltage lockout via DIP switch
Test function: Press front Test button to simulate over-temperature and trigger relay trip

✅ Alternative Selection Reference

Same brand alternative: EMT6-DBK (without ATEX explosion-proof certificate, other functions similar)

Domestic alternative: Domestic dual-channel PTC motor protection relay (note: for explosion-proof applications, domestic alternative must provide valid ATEX certificate for direct replacement of EMT6-KDB)

EATON EMT6-KDB Ambient Temperature Specifications

Open ventilated cabinet operating ambient temperature: -25℃ ～ +60℃
Sealed cabinet installation (poor heat dissipation): -25℃ ～ +45℃ (reduced upper limit)
Storage temperature: -45℃ ～ +85℃

Supplementary Notes:

Under UL/CSA certified operating conditions, the nominal rated ambient temperature on nameplate is 40℃

For ATEX explosion-proof applications, ATEX code ambient limits must be followed, not solely the 60℃ upper limit

EATON EMT6 Full Series Model List (PTC Thermistor Motor Protection Relay)

Abbreviation Definition

K: ATEX explosion-proof certified, supports sensor cable short-circuit detection

DB: Dual PTC sensor circuit

EMT62: Dual normally open contact version

(230V): Fixed 230V AC supply; no suffix = wide voltage 24~240V AC/DC

Model	Order No.	Sensor Circuits	Power Supply	Description
EMT6	66166	Single	24~240V AC/DC	Basic model, no short-circuit detection, non-explosion-proof
EMT6(230V)	66400	Single	230V AC	Single circuit, fixed 230V power supply
EMT6-DB	66167	Dual	24~240V AC/DC	Dual circuit, no short-circuit detection, non-explosion-proof
EMT6-DB(230V)	66401	Dual	230V AC	Dual circuit, fixed 230V power supply
EMT6-DBK	66168	Dual	24~240V AC/DC	Dual circuit with sensor short-circuit detection, no ATEX
EMT6-K	269470	Single	24~240V AC/DC	Single circuit, ATEX certified, with short-circuit detection
EMT6-KDB	269471	Dual	24~240V AC/DC	Dual circuit + ATEX + short-circuit detection (target model)
EMT62	171889	Single	24~240V AC/DC	Single circuit, dual NO output contacts
EMT62-DB	171890	Dual	24~240V AC/DC	Dual circuit, dual NO output contacts

Quick Selection Guide

Explosion hazardous area (Ex-e motor) → EMT6-K / EMT6-KDB
General industry, require sensor cable short-circuit detection → EMT6-DBK
General industry, dual temperature monitoring, short-circuit detection not required → EMT6-DB
Two independent normally open alarm outputs required → EMT62 / EMT62-DB

EATON EMT6-KDB (Order No.269471) Physical Dimensions

DIN rail mounted; housing dimensions identical across all EMT6 variants

Width(W): 22.5 mm (nominal 23mm, standard 22.5mm DIN rail module width)

Height(H): 83 mm

Depth(D): 103 mm (measured from DIN rail mounting surface to front face)

✅ Weight: 0.13 kg approx.

Remarks: