Chint Motor Starter Protection Switch NS2-25/4-6.3A

Chint NS2-25/4-6.3A is a starter protection switch specifically designed for three-phase squirrel-cage induction motors. It integrates the functions of a circuit breaker and a thermal relay, providing overload protection, phase failure protection, short-circuit protection, and infrequent starting control.

Model Interpretation:

NS2: Series code (N stands for Chint, S stands for Starter)

25: Frame current rating (25A)

4-6.3A: Rated current range of the trip unit (adjustable within 4-6.3A)

1. Core Technical Parameters

III. Functional Features

1. Multiple Protection Functions

Overload Protection: Built-in bimetallic thermal element acts when the current exceeds the setting current for a certain period, preventing motor burnout due to overheating.

Phase Failure Protection: Detects the loss of any phase in the three-phase power supply and immediately cuts off the circuit to protect the motor.

Short-Circuit Protection: Instantaneous electromagnetic trip unit operates rapidly (≤100ms) when the current reaches 78A, preventing the expansion of short-circuit faults.

Isolation Function: Can be used as an isolating switch to ensure maintenance safety.

2. Control Functions

– Integrates start/stop button control with a compact structure.

– Supports 35mm standard DIN rail mounting for quick deployment.

– Optional accessories available: Undervoltage Trip (UV), Shunt Trip (SH), Auxiliary Contact (AE/AU), Fault Signal Contact (FA).

1. Application Scenarios

NS2-25/4-6.3A is suitable for:

– Protection and control of three-phase induction motors with a power of approximately 2.2kW (400V).

– Control of small and medium-sized motors in factories and workshops, such as fans, water pumps, conveyors, compressors, and other equipment.

– Motor control cabinets in building automation systems.

– Can replace the traditional circuit breaker + thermal relay combination scheme, saving space and costs.

1. Usage Precautions
2. Installation Requirements

– Install vertically with an inclination angle ≤±5° to ensure reliable operation.

– The tightening torque for the terminal screws (M4) is 1.7N·m; avoid over-tightening to prevent thread damage.

– Recommended wire cross-sectional area: 1~6mm², wire stripping length: 10mm.

2. Parameter Setting

Setting Current: Should be adjusted to 1.05~1.1 times the motor’s rated current to ensure protection sensitivity and avoid false tripping.

– When the ambient temperature deviates significantly from 25℃, adjust the setting current according to the temperature compensation characteristic table.

3. Operating Restrictions

– Do not operate beyond the rated voltage or frequency.

– The operating frequency shall not exceed 30 times/hour; frequent operation will shorten the service life.

– It is strictly prohibited to disassemble or replace parts with live electricity; the power supply must be cut off first and confirmed to be de-energized.

1. Selection Reference

To select the appropriate NS2 series product for your motor:

1. First determine the motor’s rated current.
2. Choose a model whose setting current range includes the motor’s rated current.
3. Motor power reference: NS2-25/4-6.3A is suitable for motors with a power of approximately 2.2kW (400V).
4. In systems with high-order harmonics such as inverter power supply, it is recommended to select the specification according to 1.3~1.9 times the motor’s rated current.

Summary

Chint NS2-25/4-6.3A is a reliable-performance motor starter protection switch that integrates protection and control functions. It is particularly suitable for three-phase induction motors of around 2.2kW. Not only can it effectively protect motors from overload, phase failure, and short-circuit damage, but it also simplifies the design of control systems, making it an ideal choice in the field of industrial electrical control.