Soft Start Inverters – What You Need to Know Before Buying

We all want our modern world to move and run seamlessly. Our systems and processes must run efficiently to ensure maximum productivity and convenience. This is why soft start inverters have become an attractive choice for many companies and individuals. These inverters are a great way of improving a system’s performance as they help reduce the stress put on motors and other hardware by gradually increasing power. But it is important to keep in mind that not all soft start inverters are created equal. Before investing in a soft start inverter, you need to understand what sets them apart and make informed decisions. In this blog post, we will take a look at some of the key factors you need to understand and consider when buying a soft start inverter. Keep reading to find out more!

Quick Clarification

A soft start inverter is an electrical circuit designed to reduce the inrush current of an AC motor during initial startup. This type of inverter slowly ramps up the power supplied to the motor, reducing stress on both the motor itself and other connected components.

What is a Soft Start Inverter?

A soft start inverter is a specialized type of inverter that allows an AC electric motor to start with minimal current draw. Often times, when motors are running long cycles, they can be prone to damage due to their high initial current draw on startup. This is where the soft start inverter comes in. With gradual ramping up of current, it reduces the inrush current and torque on motor startup, thus protecting the motor from damage. Furthermore, this protective feature also allows for increased energy efficiency and longer cycle life due to less wear and tear on components.

As beneficial as soft start inverters can be for commercial applications, there are some drawbacks associated with them as well. Decreased control over speed and torque may require other systems like incremental gearing or more complex controls to override any issues related to speed or torque control. Additionally, since the current draw is slow, they can cause operational inefficiencies compared to other types of inverters that have precise control over their current output rapid response time.

Nonetheless, soft start inverters continue to be a critical component of most commercial AC motor systems due to their ability to protect motors better than static drives while offering good protection against surges, overloads and short circuits. With that said, let’s now look at how a soft start inverter actually works.

  • The main benefit of a soft start inverter is that it reduces the inrush current when starting a motor load.
  • According to research, a soft start inverter can reduce energy consumption by up to 30% compared to traditional inverters.
  • By using a soft start inverter, the motor will run 10%-20% cooler in most applications due to the gradual increase in voltage.

Key Takeaway

Soft start inverters are valuable components for commercial AC motor systems because they reduce the inrush current and torque on motor startup, which protects the motor from damage, increases energy efficiency and extends cycle life. However, they have some drawbacks such as decreased control over speed and torque, causing operational inefficiencies compared to other types of inverters. Soft start inverters work by gradually ramping up current output to start the motor with minimal current draw.

How Does a Soft Start Inverter Work?

Soft start inverters are an invaluable tool in industrial settings to reduce the power surge, or “inrush”, of electric motors when starting up or stopping. These inverters are typically used for AC electric motors and work by ramping up slowly over time instead of permitting the motor to be powered on at full capacity with one single voltage command. This reduces the amount of power needed for an AC motor to achieve its desired speed and torque.

The primary role of a soft start inverter is to limit the amount of current flowing into a motor when it starts. This may be done in one of two ways: by reducing the incoming voltage applied to the motor, or by applying a reduced voltage while simultaneously increasing the frequency of the incoming current.

When using this technology, current is limited to a level that is often half as much as what would occur if no inverter was being used, which can result in significant cost savings on energy bills. Additionally, soft start capability can prolong the life of both components and equipment through its low-energy startup process which helps reduce wear and tear on expensive parts.

On the other hand, there is one important drawback to consider: while soft-start inverters may seem like a safe option due to their potential to reduce costs and extend component life, they are not designed for motors with heavy loads since these heavier loads require higher currents from the start. Such motors should not be started with a soft start setup since this could cause permanent damage to either the drive or the motor itself.

Overall, soft start inverters can be incredibly effective tools for controlling AC motors in certain scenarios. By limiting an initial surge in power and gradually ramping up over time, these inverters provide reliable protection against overloads while ensuring optimum performance. With that being said, care should still be taken before installing any voltage control devices because they may not always be suitable for use with certain equipment types or loads.

With this understanding of how soft start inverters work now established, let’s take a look at some specifics about associated with three-phase AC motors in the section below.

The Three-Phase AC Motor

The Three-Phase AC Motor is the most common type of motor used in industry today. This type of motor provides a reliable, efficient, and cost effective way to run equipment such as pumps, conveyors, and other industrial machinery. However, the three-phase AC motor needs special treatment when using soft start inverters.

Without proper care and adjustment, the sensitive timing and currents of this type of motor can be adversely affected by sudden changes in voltage or current that can occur during soft start. This could result in decreased efficiency, increased downtime and costly repairs. It is important to use an inverter that can provide smooth voltage transitions during the start up process in order to avoid any damage to the motor.

Additionally, the correct current and voltage set points for the three-phase AC motor must be configured correctly on the inverter first time – if not, it won’t be able to operate safely or efficiently. This means it should only ever be handled by a qualified technician who understands how to properly adjust the soft start parameters for optimal performance.

By understanding the importance of adjusting voltage and current settings for three-phase AC motors, you will be better prepared to select an appropriate soft start inverter for your application. In the next section we will discuss how to adjust these parameters so that you can ensure optimal performance from your system.

Adjusting the Voltage and Current

Adjusting the voltage and current of a soft start inverter is not only possible, but in many cases essential to ensure proper functionality. The mechanism for adjustment depends on the type of inverter being used. In some models, such as constant-voltage (CV) models, the voltage and current are self-adjustable and won’t need to be adjusted manually. On the other hand, adjustable voltage or adjustable current (AV or AC) models allow for precise adjustment of both values.

When adjusting the voltage and current of an inverter, it is important to take into account any additional loads that may be placed on it, since too little power can cause them to fail while too much power can cause their components to overheat. Additionally, if the voltage is set too high, the device may malfunction or even become damaged due to overvoltage conditions. It is also important to consider environmental factors such as high ambient temperature or potentially hazardous materials that could be present in the area around the inverter before making adjustments.

Due to these considerations, some argue that manual adjustment of voltage and current should not be necessary unless absolutely necessary for compatibility with a particular load. On the other hand, others suggest that manual adjustment gives users more control of their inverters and allows them to fine-tune its settings for optimal performance. Ultimately, it depends on the specific requirements of each system when deciding whether or not adjusting the voltage and current is necessary.

Next, we’ll explore the benefits and advantages of using a soft start inverter.

Benefits and Advantages of a Soft Start Inverter

Soft start inverters have many different benefits and advantages that make them desirable. A soft start inverter controls the motor speed of large motor-driven systems, reducing the high inrush current when starting—which decreases their energy costs and lowers their environmental impact. The slow but steady acceleration of the motor also helps extend its life by avoiding the sudden jerking motion during rapid acceleration.

The use of soft start inverters is beneficial for both motors and infrastructure because they don’t require a lot of space or setup time, making installation easier than more complex systems. Additionally, they offer a wide variety of control options, such as torque boost, preset speeds, constant speed settings, modulation libraries, and more. Not only do they provide motor protection at startup, they also protect against many other disruptive forces, like voltage sags and spikes.

One potential disadvantage of using a soft start inverter is the cost associated with purchasing and installing the system. Soft start inverters can be expensive to set up and maintain; however, this expense can often be offset by savings on energy costs over time due to better efficiency levels for larger systems.

For those in need of reliable power control for their motor-driven systems, soft start inverters offer a great solution that delivers powerful performance in a space-saving package. With so many benefits and advantages to consider, it’s no wonder why so many are turning to these types of inverters for their industrial needs. Now that we understand the benefits and advantages of a soft start inverter, let’s look at some applications where this technology can be used most effectively.

Applications of a Soft Start Inverter

Soft start inverters are devices used to control how much power is supplied to a particular motor when it starts up. These inverters are typically used in applications that require speed control, such as compressors or pumps in industrial settings, where the increased torque produced by slowly increasing the voltage helps reduce stress on the mechanical components and prolongs equipment life. Additionally, they can also be used in situations requiring large fluctuations in speed or torque, such as conveyor systems or machine tools.

Soft start inverters offer many benefits over other types of motor control solutions. For example, they help reduce power system harmonic distortions, improve motor efficiency, reduce wear and tear on mechanical components, and ultimately lower overall energy costs. Moreover, their ability to slowly increase power output reduces starting current demand and protects the motor from thermal overload issues that can occur when a motor is started with a full-voltage application.

On the other hand, some industry experts point out the costs associated with soft start inverters and question whether these additional investments are worth it for certain applications. They claim that depending on local utility rates and motor load requirements, running equipment at full-voltage may still be more economical than using a soft start inverter.

Overall, while there are always considerations to be taken into account before investing in any type of motor control solution, the advantages provided by soft start inverters make them an attractive option for many industrial applications. With this in mind, let’s now take a look at the various types of technologies available for modern soft start inverters.

Technologies for Soft Start Inverters

Soft start inverters provide several advantages over traditional inverters, making them ideal for a wide range of industrial and commercial applications. One of the most widely used technologies in these types of inverters is soft start technology. Soft start technology has been widely adopted by industries due to its advantages such as lower starting current draw, reduced mechanical shock, increased system life, and better motor control.

The main technology behind soft start inverters is their ability to reduce the peak current at startup. This reduces the amount of mechanical shock on the motor, increases system life by reducing the amount of stress on the motor and its components, and can also provide better torque control over the full speed range. In addition to this, soft start inverters are also much more energy efficient than traditional inverters because they generate less heat while providing power to motors.

Many people debate whether or not soft start inverters are truly worth their cost. On one hand, they can be expensive to purchase due to their higher quality components and implementation costs. On the other hand, using them results in fewer stalling issues, greater energy efficiency and longer system life. An effective soft start solution that reduces peak current draw upon startup can improve system performance as well as save money over time as it will extend motor life expectancy.

Ultimately, it is important for buyers to choose the correct type of soft start solution for their application before investing in an inverter solution. However, by taking into consideration all of the factors discussed here including cost efficiency and system longevity, it is clear that utilizing a soft start inverter is recommended over traditional alternatives if feasible for your application needs.

Ready for a conclusion? Let’s take a look at what you need to know before buying a soft start inverter solution and how to make sure you make the best decision for your project in the next section.


Given the wide range of soft start inverters on the market, it can be difficult to decide which one is best suited to your needs. Ultimately, it comes down to your specific requirements regarding size, voltage, and capability. The overall cost of the unit will also be a major factor in deciding which type of soft start inverter you purchase.

In addition to considering size, voltage and capability when selecting a soft start inverter, you should also consider its ability to provide a fast and reliable startup. This is crucial for applications that need to respond quickly and accurately when called upon. It’s important to remember that not all soft start inverters are equal in this regard. Some may offer improved speed and reliability while others may lack these features.

Finally, it’s worth exploring any warranty or guarantee offered by the manufacturer before making a purchase decision. Many soft start inverters come with extended warranties that guard against any unexpected issues that may arise during use or operation. Such guarantees can give added peace of mind in the unlikely event that something does go wrong.

Overall, selecting the right soft start inverter for your particular application requires careful thought and consideration of various factors such as size, voltage, capability and cost. With so many different models on the market today it’s important to compare each option before settling on one choice. Taking into account the points mentioned above will help you to find an efficient and reliable piece of equipment that ultimately meets your needs while avoiding any unwelcome surprises down the road.

Answers to Common Questions

How does a soft start inverter work?

A soft start inverter is a type of power converter that helps deliver controlled, reliable power to motors and other heavy-duty power loads. These inverters work by gradually increasing the voltage as the load current increases, allowing for a more gentle and efficient ramp up of power. This greatly reduces the mechanical and electrical stress on connected components, preventing sudden large inrush currents that can damage or overheat them. The slower ramping also minimizes wear and tear on the supporting infrastructure, resulting in improved system stability and longevity. Soft start inverters are particularly useful for powering industrial equipment and motorized applications such as pumps and compressors.

What are the advantages of using a soft start inverter?

The advantages of using a soft start inverter are numerous. First, it can provide a smooth starting experience for machines and equipment that are prone to drawing high inrush currents. This is because it reduces the peak current draw at startup, thus decreasing stress on motor windings and prolonging motor life. Additionally, soft start inverters can reduce mechanical stresses caused by high torque requirements at startup, leading to fewer equipment failures and repair costs. Furthermore, this type of inverter can be integrated with energy-saving strategies such as varying the speed of the motor during operation or creating low-power operational segments of the cycle. Finally, soft start inverters can increase system efficiency when compared to other control methods due to reduced power losses, improved efficiency of the motor through dynamic acceleration and more precise motion control.

What are the applications of a soft start inverter?

Soft start inverters are widely used in a variety of applications due to their ability to control the speed and direction of motors. Common applications include industrial production machinery, automated equipment like robots, conveyor belts and pumps, elevators, cranes, escalators, HVAC systems, medical equipment like MRI machines and x-ray machines, and automated retail.

Soft start inverters bring several advantages over other types of motor control solutions such as reduced wear and tear on motors from harsh starting conditions, improved motor performance during operation due to more efficient torque/speed curves, and improved overall energy efficiency since they reduce power draw upon startup. Additionally, these inverters can be used for noise reduction of motors and compressor systems by gradually increasing the speed of a motor without causing an abrupt jump in load. This can help improve the quality of life for employees or those living nearby industrial settings.