Three Phase 220v 400v 690v Built-in Bypass Motor Soft Starter 7.5–630kW

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The bypass motor soft starter is a soft starter developed by our company based on the latest product architecture platform that supports multiple bypass types. The architecture has been greatly optimized and improved in software and hardware.

Based on the latest 32-bit ARM architecture main control chip, the algorithm performance and functions are further improved. The high-frequency optocoupler-triggered thyristor design replaces the traditional analog pulse drive, which effectively improves the internal conduction efficiency of the thyristor and reduces losses.

The built-in bypass contactor design enables the product to adapt to wide voltage fluctuations. The product also has linear temperature detection, adjustable three-phase unbalance tolerance and overload tolerance design, so that it can better adapt to the harsh production environment.


The NK700 built-in bypass contactor soft starter components, materials and the latest microcomputer control technology. This product is a star-sto manufactured using high-quality device that integrates motor soft start, soft stop, energy saving and multiple protection functions and is dedicated to use a constant speed AC motor as the driving power.

Compared with the traditional starting method, after using the NK700 built-in bypass contactor soft starter, the voltage, torque and current on the motor can work smoothly, so the mechanical impact of the load will be completely improved; rich motor protection functions , lt has played a very important role in extending the service life of the motor; at the same time, it has the communication function with the host computer control system, which can effectively implement the networking function of the system.

1. Multiple starting modes

User is allowed to choose current-limiting start and voltage ramp start and apply programmable kick start and current limit in each starting mode so as to largely meet this site application and achieve the optimal start.

2. High reliability

High performance microprocessor digitally processes signals in control system, which avoids excessive adjustment in previous analog line and obtain the perfect accuracy and execution speed.

3. Built-in bypass contactor

The built-in bypass contactor uses no electricity running technology, different from other external bypass contactor charged operation mode for a long time, so this product is power saving, no noise, no electromagnetic pollution, does not produce sparks, green environmental protection.

4. Standard MODBUS-RTU protocol

When placing an order, user can choose the model with standard MODBUS-RTU communication protocol or not according to the need of application.

5. Integrated with advanced protective function

Protective functions of phase failure, overload, overcurrent, phase current unbalance, thyristor overheat to protect motor and other equipment.

6. Easy maintenance

The monitor signal coding system consists of lcd display monitors working state of the equipment for 24 hours and provides fast fault diagnosis.


Rated Main Voltage: 380VAC,690VAC
Motor Power: 5.5--630kW
Adjustable starting time: 1--120s
Adjustable stop time: 0--120s
Power frequency: 50/60Hz
Adaptive Motor: Squirrel-cage three-phase asynchronous motor
Control Source Voltage: 100~240VAC
Start frequency: Depending on the load, no more than 20 times per hour are recommended
Control mode: 1. Ramp voltage 2. Ramp current 3. Current limit
Digital input: 3 channels
Analogue output: 1 channel 4-20mA/0-10V
Relay output: 2 relay output
Running command input: 1. Keyboard display unit setting 2. Control terminal setting 3. RS485 communication is given
Communication: Standard Modbus protocol, 1 channel
Protection Class: IP42
Cooling Pattern: Natural wind cooling
Place to be used: Indoor location with good ventilation free from corrosive gas and conductive dust.
Environment Condition: Maximum altitude:1000m(3280 ft) Operation Environmental temperature:0 ℃ to + 50 ℃ (32 ºF to 122 ºF) Store temperature:-40 ℃ to + 70 ℃ (-40 ºF to 158 ºF)

Product Details:

The main structure of built-in bypass motor soft starter shell is plastic shell, advanced surface powder spraying and plastic spraying technology, with compact dimension and beautiful appearance. Adopt the famous brand of SCRs in China. All the pcb board with strict test before dispatch. The bypass motor soft starter is a very ideal motor starting equipment. It has successfully replaced the star triangle starter, self-adjusting voltage-releasing starter.


1. For ordinary load: The corresponding bypass motor soft starter models can be selected according to the rate current of motors marked on the motor namaplate, such as pumps, compressors, etc.

2. For heavy load: The built-in bypass motor soft starter model of large power size can be selected according to the rated current of motor nameplate, such as centrifuge, crushing machine, mixed, etc.;

3. For frequent start load: According to the rated current of the motor marked by the motor nameplate, we choose a higher power size motor soft starter.


Bypass motor soft starter can be widely used as below:

1. Water pump

In a variety of pump applications, there is a risk of power surges. This risk can be greatly reduced by installing a motor soft starter and gradually feeding the current into the motor.

2. Conveyor belt

When using a conveyor belt, a sudden start is likely to cause problems. The belt may pull and become misaligned. Regular starting also adds unnecessary stress to the belt's drive components. By installing a motor soft starter, the belt will start more slowly and the belt is more likely to stay on track properly.

3. Fan and similar systems

In systems with belt drives, the potential problems are similar to those that arise with conveyor belts. A sudden, sharp start means the belt is in danger of slipping off the track. Motor soft starter can solve this problem.

4. Others

Customer Service:

1. ODM/OEM service is offered.
2. Quick order confirmation.
3. Fast delivery time.
4. Convenient payment term.

At present, the company is vigorously expanding overseas markets and global layout. We are committed to becoming one of the top ten export enterprises in China’s electrical automatic product, serving the world with high-quality products and achieving a win-win situation with more customers.

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