Soft Starter Schneider

Thông tin chi tiết

What is soft start? What is the structure and operating principle of soft starter? How to connect and apply soft start in practice? Amazen will answer you all the basic information about Soft Start through the article below!

1. What is Soft Start?

- Soft starter, also known in English as Soft Start, is an electrical device used to support the starting process of medium and large capacity 3-phase asynchronous motors. Helps protect the motor from damage due to large and sudden starting currents, and avoids grid system voltage drops that damage other electrical equipment on the same grid and cause mechanical effects.
- Soft start is a start that uses an AC voltage converter to control the stator voltage of the motor by controlling the SCR excitation angle. The advantage is smooth adjustment, wide adjustment range. Flexibly combine soft start and soft stop.

2. Uses of soft start (Soft Start)

- Soft start helps reduce the impact on mechanical equipment, thereby helping to reduce maintenance costs significantly.
- When it comes to soft starters, one of the biggest benefits is the ability to adjust torque very precisely when needed whether the application is loaded or not.
- Besides, a quite prominent use of the Soft Starter is the soft stop function, this function is really useful when stopping the pump, where water hammer phenomena occur when stopping directly such as in star starting, starting triangulation and direct start.
- The soft stop function is also useful when stopping conveyors transporting fragile materials, which can be damaged when the belts stop too quickly.

3. Structure of soft start (Soft Start)

The structure of soft start includes:
- Control unit (depending on type with screen and keyboard or controlled by screw or installed by turning rheostat)
- Thyristor or SCR (Silicon controler rectifier) is used to control, switch on and off electric current
- Heatsink and cooling fan
- Protective cover depends on the type according to the protection standards due to the environment used
- Contactor Bypass (depending on whether the soft starter is available or not)
- Control unit: digital or mechanical control, status relay outputs, overheating and overload protection control, Modbus, Profibus communication ports, start-up time control by resistor or by screen

4. Working principle of soft start (Soft Start)

- The main operating principle of the soft starter is to help operate the motor through controlling the voltage supplied to the motor when starting and stopping, which means changing the effective value of the voltage. Because the motor torque is proportional to the square of the voltage, but the voltage is proportional to the current and acceleration torque, therefore, adjusting the input current when the motor starts will adjust the voltage. get the effective value of the voltage.
- The structure of each soft starter device will include 3 pairs of thyristors (SCR) connected in parallel and opposite each other. When the device is in the on/off state, these thyristor pairs will prevent current from flowing.
- But on the contrary, when the device is in the open state, the thyristor pairs will gradually open the excitation angle of the semiconductor valves, allowing current to flow but preventing current from flowing simultaneously massively, but slowly, It not only provides energy for the starting engine, but also helps the engine accelerate slowly, not too quickly causing the electrical system to lose voltage.
- The opening angle of the semiconductor valve is the "key" to adjusting the voltage supplied to the device and motor. The valve opens slowly until fully opened, the voltage will reach the maximum rated voltage value, which is also when the motor has reached maximum speed and operates stably.
- When the motor has reached the rated speed limit, the soft starter's bypass contactor feature will automatically close, without going through the thyristor.

5. How to connect soft start (Soft Start)

- Direct type (the most common and relatively simple connection type): You only need to supply 220Vac power source directly to the soft starter device to provide power, then the OUTPUT output of the device is connected to electric motor, can be a current greater than or equal to the rated current of the motor, 3-phase power, the INPUT input of the device will be connected to the load motor, then attached to the Contactor Bypass, Relay output depending on the type of device.

- In parallel: The motor is connected to 6 wire terminals, 3 terminals with soft starter, the remaining 3 terminals of the motor with soft starter connected to the grid. Choose a soft starter with a current equal to 58% of the motor's rated current. This method must have 2 contactors, 1 for Bypass (can be built into the soft starter and 1 Contactor for Delta connection).

6. Characteristics of soft start (Soft Start)

- Allows the motor to stop freely according to inertia, to cope with situations where the input voltage is stopped directly, the motor can still continue to stop according to the inertia of the motor's rotation, for a period of time. identify.
- Allow the motor to soft stop, from which the voltage of the motor with soft start device will decrease slowly and in about 1 - 20 seconds (depending on requirements)
- Save more energy when the motor operates at no load or under load, because soft start helps reduce the motor voltage to the value U0, thereby reducing voltage, reducing current, minimizing costs Multi.

7. Instructions for choosing soft start (Soft Start)

When choosing a soft starter suitable for your needs, you should pay attention to the following issues:
- Know the application characteristics
- Understand the engine capacity to choose a soft starter with the appropriate rated current
- Installation location
- Investment costs

8. Advantages and disadvantages of soft start (Soft Start)

Advantage
- More compact, saves investment costs compared to inverters of the same capacity
- Can be used in conjunction with a motor to adjust motor speed
- Can be adjusted smoothly, wide adjustment range, soft stop, slow acceleration,...
- There are full features to protect the motor and power network when phenomena such as overcurrent, overvoltage, phase loss, phase reversal, etc. occur, making the motor more durable and protecting devices connected to the system. electricity
- Save energy, save on electricity bills
- Helps adjust engine speed easily without affecting technology requirements, equipment structure, machinery or power grid system
Defect
- Not very suitable for large engines, heavy starting, too difficult starting, because the adjustment range of acceleration - deceleration time is relatively narrow
- Difficult to construct, difficult to maintain
- Because using the principle of changing input voltage to change motor speed can cause weak starting torque, it is necessary to know how to choose a suitable soft starter

9. When should you use soft start?

Soft starter should be used in the following cases:
- Need to support the starting process, stopping process of the engine, acceleration or deceleration during starting of the engine, cannot reverse the engine
- Helps protect the motor against unwanted incidents such as: overcurrent, overvoltage, phase loss, overload, short circuit for the load,...
- A soft starter can only be used with a single engine
- Helps protect the motor, increases motor life, reduces investment costs, because it has a lower cost than an inverter, and also helps reduce monthly maintenance costs.
- Need to limit grid voltage drops

10. Application of soft start (Soft Start)

- Soft starters are often used to start motors with high average capacity that do not require changing speed or reversing the motor during operation.
- Soft starters are used in applications that only require speed and torque control during starting. Or when there is a requirement to reduce large starting currents associated with large motors.
- In pumping applications, soft starting can avoid pressure surges.

- Soft start can be set according to each application's requirements. Some soft starters include a “learning” process to automatically adjust control settings according to the characteristics of the motor load, to reduce the need for power up at starting.
- Soft starters are seen in electric R/C helicopters, and allow the rotor blades to rotate automatically in a smooth, controlled manner rather than with sudden surges.
- In all systems, soft starting limits the inrush current and thus improves power supply stability and transient voltage drops that can affect other loads.
- Soft starter replaces direct starters or star-delta circuits.
- The conveyor system can be started smoothly, avoiding jerks and stress on the transmission components.
- Fans or other systems with belt drives can be started slowly to avoid belt slippage.

11. Top Soft Start brands to use

Chint brand
- Manufactured by Chint electrical equipment company, one of the leading electrical equipment manufacturing brands in China and famous worldwide. Chint soft starter is a high quality product line, most widely used today in Vietnam.
- Chint soft starter applies the latest technology, so it has many superior features, high stable working ability and, more importantly, absolute safety for users. High durability and especially suitable for hot, humid and rainy environments in Vietnam.
Refer to Chint soft start details at: Thiết bị tự động hóa Amazen

Schneider brand
- Schneider soft starter is responsible for protecting the motor from overheating, no load, overload, stuck rotor or reverse due to inertia.
- Soft start is integrated with communication modbus, Ethernet, FIPIO, Profibus DP.
- Allows simple parameter setting as required via the built-in screen or software.
- The soft stop function is useful when stopping the pump or stopping the conveyor belt transporting fragile objects that can be damaged when stopping too quickly.
- Ability to report status errors, low load, and phase loss errors.
- The screen of the Schneider soft starter is clear, displaying 4 numbers, 4 function keys and 4 light-emitting diodes.

Where to supply cheap Schneider soft starters: https://amazen.com.vn/khoi-dong-mem/schneider.html

LS brand
- Picked from high-quality raw materials to produce under strict technical supervision. Therefore, customers can be completely assured about the quality of the soft starter product line from the LS brand.
- Along with premium quality, soft starters play an important role in many areas of industry. Work with high reliability on engine protection and operation needs. The quality and performance of the LS soft starter is confirmed through long-term use over many years. Very rarely does damage occur, thus limiting costly repairs and replacements.

Siemens brand
- This brand affirms its reputation, quality, durability over time, easy installation and operation, very high working reliability, very safe for operators. Manufactured according to the technology Latest technology, Siemens soft starters conform to the industry standards of other products. Siemens soft starters have many types for customers to freely choose from and have many more advantages, especially suitable for options for industrial applications.

Above are the Soft Starter brands with high quality and affordable prices that Amazen introduces to you. Amazen wishes you to find a soft starter that suits your needs!
Epilogue
In case you need to learn, need technical advice and order Soft Start, please contact Amazen immediately via:
Hotline: 0934 399 068 - Sales: 0938 072 058
Email: amazen@amazen.com.vn
With a team of highly specialized technical support and sales consultants, our company is confident that it will bring customers the best purchasing experience.
Amazen commits that all inverter products we currently offer are genuine, 100% brand new, quality guaranteed and fully accompanied by certification documents.