Chint NJBK2 Motor Protection Relay
Chint NJBK2 Motor Protection Relay
Chint NJBK2 Motor Protection Relay
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Chint NJBK2 Motor Protection Relay
Chint NJBK2 Motor Protection Relay
Chint NJBK2 Motor Protection Relay
Chint NJBK5 Motor Controller
Chint NJBK5 Motor Controller
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Chint NJYB3 Voltage Protection Relay
Chint NJYB3 Voltage Protection Relay

Chint NJBK2 Motor Protection Relay

Size:Miniature
Brand Name:Chint
Theory:Electromagnetic Relay
Place of Origin:China
application:PROTECTIVE
Model Number:NJBK2
Contact Load:High Power
Protect Feature:Sealed
Rated Voltage
Current Setting Range (A)
SKU: 1769741905949630464 Category:
Description

Chint original NJBK2 NJBK2-200 NJBK2-400 NJBK2-800 Overload Locked rotor Phase failure Unbalance Earthing Motor Protection Relay

   

Chint NJBK2 series motor protection relay (hereinafter referred to protector as simply) is applicable for overload, locked-rotor, phase-failure, three phase current unbalance, earthing and PTC temperature protection of AC motor @ A.C.50Hz, less than 690V rated insulation voltage and 1A ~ 800A rated operating current for its continuous working or discontinuous working. This product meets the requirements of IEC 60947- 4-1.

 

 
Additional information
Current Setting Range (A)

0.5-1A, 1-3.2A, 2.5-8A, 5-16A, 10-32A, 20-63A, 40-100A, 63-160A
Rated Voltage

AC 380V
Technical Datasheet & Downloads

📄 Technical Documentation & Product Specifications

Download official engineering datasheets, certified test standards (IEC / UL / CE), wiring diagrams, and dimensional drawings for Chint NJBK2 Motor Protection Relay.

📥
Official Technical Datasheet (PDF) Complete electrical ratings, tripping characteristics, dimensions, and compliance specifications.
Request Official Datasheet (PDF)
📐
2D/3D CAD & Dimensional Drawings STEP, DXF, and PDF CAD drawing files for panel builders and switchgear designers.
Request CAD Model
Certified Standards: IEC 60898-1, IEC 60947-2, CE, RoHS, ISO 9001:2015
Manufacturer: Shanghai Newtrend Electric Co., Ltd. (Global Export Compliance)
Engineering Support: 24-hour response for custom voltage ratings, auxiliary contacts, and technical consulting.
Technical FAQ & Selection Guide

💡 Frequently Asked Technical Questions & Selection Guide

Pure engineering specifications, tripping curve parameters, and electrical selection guidance for panel builders and system designers.

AC-1 / AC-3 Duty

How to calculate contactor rating based on motor power and utilization categories (AC-1 vs AC-3 vs AC-4)?

A

AC-3 rating applies to standard squirrel-cage motor starting and stopping during normal run (starting current 5–7x In). For non-inductive or purely resistive heating loads, use the higher AC-1 rating. For severe inching, jogging, and plugging applications (AC-4 duty), derate the contactor or upsize by 1 to 2 frame sizes to prevent contact erosion.

Coil Voltage Selection

How to choose the correct control coil voltage, frequency, and electronic wide-voltage options?

A

Standard AC coils include 24V, 48V, 110V, 220V/230V, 380V at 50/60Hz. For DC control loops or PLC outputs, specify DC coils or electronic wide-range AC/DC coils (e.g. 100V–250V AC/DC) which feature built-in surge suppression, low holding power consumption, and immunity to voltage dips.

Overload Coordination

How to size and coordinate the matching thermal overload relay (TOR) for Type 2 protection?

A

Select a thermal overload relay whose current setting range straddles the motor full-load current (FLA). Set the dial precisely to 1.0x motor nameplate FLA. For IEC 60947-4-1 Type 2 coordination, pair the contactor and relay with backed-up upstream fuses or fast-acting MCB/MCCB to prevent welding under fault conditions.

Auxiliary & Interlocks

What auxiliary contact blocks and mechanical interlocks can be added for motor reversing?

A

Units feature built-in 1NO or 1NC auxiliary contacts, expandable with top-mounted 2-pole or 4-pole auxiliary contact blocks (F4 / AX) and pneumatic timer delay blocks. For forward/reverse motor starters or star-delta starter assemblies, add side-mounted mechanical interlock units (MI) with electrical interlocking.

Ambient & Altitude Derating

How do ambient temperature and installation altitude affect contactor performance?

A

Standard ratings are calibrated for -5°C to +40°C. For ambient temperatures exceeding 55°C or altitudes above 2000m (where reduced air density diminishes heat dissipation and dielectric insulation), derate operational current by 2% per 100m above 2000m and verify insulation voltage limits per IEC standards.

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