NJBK6 Motor Overload Relay

CHINT NJBK6 series motor overload relay are designed to protect AC motors that operate continuously or intermittently at frequencies of up to 50 Hz, with rated insulation voltages below 690V, rated operating currents between 1A and 36A, and locked rotors from overload, phase failure, and three-phase current imbalance.

Reference: IEC 60947-4-1

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Features of Motor Overload Relay

  • Features include open-phase, three-phase current unbalance protection, inverse time overload protection, and overload given time protection (on/off);
  • Four built-in overload curves are available to accommodate various situations;
  • panel with start and stop buttons, terminal block that may be externally connected and has easier wiring for start and stop buttons;
  • Start-up delay and auto-start function can be enabled and closed, respectively. When the electricity is restored or reset following a power outage, the protector initiates automatically, without requiring human input, based on the predetermined auto start delay;
  • Memory faults and their symptoms: When a motor fails, the bottom row LED flashes and shows the fault code, and the indicator shows the type of defect;
  • Screw mounting is the mounting mode.

Application of NJBK6 Motor Overload Relay

  • Control and protection of motors for various drives
  • Relay setup and commissioning times are shortened by application-specific standard configurations.
  • Preconfigured utilities and industrial applications solutions

Specification of NJBK6 Motor Overload Relay

  1. Altitude: not more than 2,000 meters;
  2. The ambient temperature is between -5°C and +40°C, and the 24-hour average shouldn’t be higher than +35°C.
  3. Atmospheric conditions: At a maximum temperature of +40°C, the relative air humidity should not be higher than 50%. At lower temperatures, the relative humidity may be higher. For instance, at +20°C, the air humidity may reach 90%. If the product occasionally develops condensation as a result of temperature fluctuations, special precautions should be taken;
  4. Level of pollution: 3.
  5. There should be no more than ±5° of inclination between the mounting plane and the vertical plane;
  6. In non-explosive media that don’t have enough gas or conductive particles in them to corrode metal or fail the insulation;
  7. In locations devoid of vapor and equipped with rain and snow protection devices;
  8. In places where there is no significant shake, impact or vibration;
  9. Mounting category: Ⅲ
No. Setting current multiple Operation time Starting conditions Starting conditions
1 1.05 No operation within 2h Cold state +20℃
2 1.2 Operation within 2h Hot Start +20℃
3 1.5 Operation within 2min Hot Start +20℃
4 7.2 2s<Tp≤10s Cold state +20℃