Soft Starter
Reliable Soft Starters for Industrial Motor Control
RENLE soft starters are designed to solve common motor starting problems in industrial applications. Built with advanced thyristor control technology, RENLE soft starters effectively limit motor starting current while allowing flexible adjustment of starting current ratio and starting time, enabling smooth soft start and soft stop performance.
With a protection rating of up to IP54 and strict compliance with IEC 62271-200 standards, RENLE soft starters provide reliable motor protection for demanding industrial environments.
They effectively reduce inrush current, mechanical stress, voltage fluctuation, and grid disturbance during the start-up of equipment such as fans, pumps, compressors, conveyors, and other industrial motor-driven systems. By protecting motors and connected mechanical equipment, RENLE soft starters help extend equipment service life, improve operational stability, and reduce maintenance costs.
With stable performance, strong protection, and flexible control, RENLE soft starters are an ideal solution for industrial motor starting applications.
Why Choose Us
Professional Team
The company insists on people-oriented and technological innovation, and the R&D team accounts for more than 30% of the total number of employees. Invested heavily in the introduction of a complete set of precision instruments and experimental equipment.
Sales Market
Our product Export United States, Vietnam, Japan, Britain, Italy, Russia, India, Brazil, Spain, the Middle East and other countries and regions.
Rich Experience
We has 20+ years of research, 120 Professional sales service, engineers / person and 35 Presence in /countries.
Soft Starter - Overview
A soft starter is an electronic device used to control the startup of an AC electric motor by gradually increasing the voltage, which reduces the sudden inrush current and mechanical stress. This "soft start" protects the motor and connected equipment from damage, prevents power surges, extends equipment life, and can even reduce energy use by providing controlled acceleration and deceleration.
Product Specification
We offers the following product specifications：
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Data Name |
Working Range |
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Frequency |
50Hz/60Hz±2Hz(selected according to user's grid) |
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Overload capacity |
400% control nominal value 60s |
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500% control nominal value 30s |
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Applicable motor |
Three-phase squirrel-cage asynchronous and synchronous motor |
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Application environment |
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Temperature |
Cabinet temperature 0°C~40°C, (Heater is optional for -20°C~0°C) |
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Humidity |
5%~95% relative humidity |
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Altitude |
Below 2000m. Derating is necessary for altitude above 2000m. |
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Place |
Indoors, no explosive or corrosive gas, with low dust |
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Cooling |
Natural cooling |
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Structural features |
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Protection level |
IP4X |
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Operation power supply |
2kVA AC220V supplied by the user (can be specified). |
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Main circuit |
The number of thyristors is determined by the model. |
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Communication protocol |
Integrated Modbus RTU, Modbus TCP, CAN and PROFIBUS DP communication protocols, equipped with interface. |
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Communication interface |
RJ45 |
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Operation interface |
7-inch touch screen (HMI) which monitors system status in real-time. Used for setting and modifying parameters. |
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Event record |
It can continuously record events and historical curves with time and date stamps within 10 days. |
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Performance monitoring |
Current, voltage, power factor, module temperature, RC average and peak voltage, RC current, etc. |
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Input and output options |
10 channels of 24VDC programmable inputs, 2 channels of 16A and 4 channels of 5A programmable outputs, 1 analog programmable output (4~20mA). |
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User management |
Multi-level user password protection (can be specified). |
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Interface language |
Chinese, English, Russian (can be specified) |
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Thyristor |
Thyristor valve group in series |
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Drive and data |
Dual power supply triggering, optical fiber communication multiplexing technology; |
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Adopting synchronous phase-locked loop, three-phase conduction compensation algorithm; |
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Equipped with OBD and software double overvoltage function; |
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After startup is completed, the valve group limit data are counted for evaluating the system status. |
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Monitoring |
HMI window, used for real-time monitoring of system status, collection of valve group data and setting and modification of control parameters. |
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Protection |
Under voltage, overvoltage, phase loss, overheating, abnormal voltage sharing, abnormal RC current, thyristor failure, optical fiber communication interruption, abnormal triggering power supply etc. |
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Cloud service |
Remote software update, commissioning, data waveform monitoring and fault analysis is realized through InterNet; |
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After connecting to the cloud server through industrial Ethernet + 5G, the soft starter provides data for big data analysis and related AI algorithms; |
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makes full use of the computing power of the cloud platform to realize online analysis and diagnosis of motor operating status, and realizes fault pre-warning and optimized control. |
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Cabinet color |
Selected by the user. |
Advantages of Soft Starter
Reduced power draw at startup
They help prevent power surges by gently starting the motor with less electricity.
Less risk of voltage dips
Smooth acceleration prevents other equipment from tripping or lights from dimming. This is especially important on weak grids or generators.
Adjustable ramp-up and ramp-down
Acceleration and deceleration can be tailormade to fit the machine or process.
Controlled start
The motor stays cooler during startup, so it can start more often without problems.
Extended equipment life
Reduced shock lowers wear on belts, gears, and other mechanical parts.
Improved system reliability
Monitoring catches problems early, like blockages, dry runs, or belt slips. This helps to prevent bigger issues.
Flexibility
Versatile start/stop or strong vector braking. Wide choice of communication options.
Cost effective
Long lasting and coated boards to withstand tough conditions. Built-in load monitor that protects your investment from damage.
Types of Soft Starter
Primary Resistor Soft Starters
Primary resistor soft starters are among the earliest soft starters, dating back to the early 1900s. They use three resistors, one for each phase of the electrical current, to limit the inrush current during startup. Gradually increasing voltage allows for smoother motor acceleration. Once the motor reaches a set speed, a timer removes the resistors from the circuit, enabling full-power operation.
Autotransformer Soft Starters
Autotransformer soft starters are among the most efficient motor startup options. Instead of resistors, they rely on transformer windings with adjustable taps to regulate voltage and current. By selecting different taps, operators can control the amount of power sent to the motor, ensuring a smooth and controlled startup.
Part Winding Soft Starters
With a part-winding soft starter, the motor windings must be divided into two or more separate sets intended for parallel operation. During start-up, power is only applied to one set of windings, but as the motor reaches speed, power is applied to the other set to resume normal running. Windings energized this way produce a reduced starting current and torque. Part-winding also minimizes voltage drop and excessive heat during start-up.
Solid-State Soft Starters
Solid-state starters are the most common overall, as well as the newest and most effective method, replacing mechanical components with electrical ones using a silicon control rectifier, or SCR. The SCR controls the motor's voltage, current, and torque during motor acceleration. It also can rapidly switch heavy currents, meaning the soft starter can provide smooth, step-less acceleration, which is considered the smoothest soft start method.
Application
Pump Applications
In various pump applications, there is a risk of power surges. By installing a soft starter and feeding the electrical current to the motor in a gradual progression, this risk is greatly reduced.
Conveyor Belts
With conveyor belts, it's always possible that a sudden start may cause problems. The belt may jerk and become misaligned. The conventional start also adds unnecessary stress to the belt's drive components. By installing a soft starter, the belt will start up more gradually and the belt has a greater chance of staying properly on track.
Fans and Similar Systems
In systems with belt drives, the potential problems are similar to the ones that arise with conveyor belts. The sudden and jerky start means the belt is at risk for slipping off its track. A soft startup corrects this problem.
Electrical Helicopters
It's not difficult to see why it could be disastrous for a helicopter to have a sudden, jerky start. If the propellers start suddenly and violently with a sudden surge, this could be dangerous. Instead, a soft start allows the propellers to start smoothly.
Components of Soft Starter
Thyristors (Silicon-Controlled Rectifiers – SCRs)
Thyristors are significant components in controlling the motor’s voltage during startup. They act as electronic switches that gradually increase the voltage supplied to the motor, helping to prevent the high inrush current typically associated with motor startups.
Control Circuit
The control circuit regulates the operation of the thyristors. It adjusts the firing angle of the thyristors, controlling how quickly the voltage is ramped up and ensuring smooth motor acceleration. The control circuit also handles fault detection and protection features.
Bypass Contactor
After the motor reaches its full operating speed, the bypass contactor is activated to bypass the thyristors. This allows the motor to operate at full power without interference from the soft starter components, ensuring maximum efficiency.
Overload Protection
Some soft starters include an overload protection mechanism to safeguard the motor from excessive current. This feature prevents the motor from overheating or sustaining damage if the current exceeds a safe threshold during startup.
Thermal Protection
Thermal protection monitors the temperature of both the motor and the soft starter. If the temperature rises beyond a safe limit, it can trigger a shutdown or alarm to prevent overheating and potential damage.
User Interface (HMI – Human-Machine Interface)
Modern soft starters have a user interface that allows operators to configure settings, monitor performance, and troubleshoot problems. This feature makes it easy to adjust parameters such as ramp-up time, maximum voltage, and motor protection settings.
Ramp Control Circuit
The ramp control circuit determines the speed at which the motor accelerates from zero to full speed. It gradually increases the voltage supplied to the motor, reducing mechanical and electrical stress during startup.
Customization Process
Requirement Discussion
Contact us and provide your design drawings, size specifications, and other technical parameters.
01
Design Proposal
Our professional team will develop a design proposal and provide a quotation based on your requirements.
02
Sample Production
We produce samples according to the design proposal and conduct rigorous testing.
03
Mass Production
Upon your approval, we commence mass production to ensure timely delivery and consistent quality.
04
After-Sales Service
We offer ongoing technical support and service to ensure the long-term stable operation of our products.
05
Package & Delivery
Package: Standard export package or Custom
Delivery: By air express, by sea
FAQ
We're well-known as one of the leading soft starter manufacturers and suppliers in China. Please feel free to buy customized soft starter made in China here from our factory. For pricelist and quotation, contact us now.