What is a Soft Start? Exploring the Benefits of Soft Starting Motors

The development and tinkering of electric motors has come a long way since their inception in the early 1800s. Today, they are an essential part of almost every aspect of our lives, from powering car engines to washing machines – the list is nearly endless. However, all motors are only as good as their starting mechanisms, and a bad start may quickly result in blown fuses, thermal overload, and even severe mechanical damage. To mitigate this risk, many motors are powered with a soft start, which provides a smooth start up and helps reduce strain on the equipment. In this blog post, we will dive deeper into what a soft start is and the benefits of using soft start motors. Let’s get started – no more waiting around!

Quick Review

A soft start, or ramped power on, is an electronic design method that gradually increases voltage or current to an circuit over time. This helps to reduce the inrush current and prevents damage due to power spikes when the device is turned on.

What is a Soft Start?

A soft start is an electrical engine starter device that limits the amount of current used to power a motor at startup. This leads to smoother, more efficient motor operation than traditional hard starting systems, which usually involves sudden surges of power. The primary purpose of a soft start system is to reduce the large inrush of current when starting, as well as providing many additional advantages.

Proponents of the soft start often point towards energy saving effectiveness and improved control and safety features. They are especially useful for large motors with long starts or multiple starts because they can limit temperature rises, ensuring a better lifetime performance of the motor. Soft starters provide better operation in terms of torque or speed control and damage protection while still providing optimal energy efficiency.

On the other hand, some users may not be aware of the long-term savings associated with the use of soft starters instead of traditional start up options and therefore not consider them as a cost-effective solution. In addition, because soft starters rely on external conditions such as voltage supply, ambient temperature and mechanical load at startup, certain valves within motors will wear out slowly over time due to higher number of startups and stops. Finally, due to current limitations, further automation may require more complex controlling devices with riskier configurations.

Having discussed what a soft start is and its pros and cons we now turn to look at its main advantages in more detail. The following section will explore the main benefits of using a soft start system for motors.

Advantages of a Soft Start

The many advantages of a soft start make it an attractive option for those looking to reduce maintenance costs and increase the lifespan of their machinery. Soft starts help motors start up more efficiently, gently, and in a controlled manner. This reduces wear and tear on the equipment, leading to increased motor efficiency and reduced motor noise. Furthermore, soft starts can often be set with adjustable torque settings so that the motor is not excessively overworked, further reducing maintenance costs.

Soft starts also have advantages for safety. When a motor suddenly kicks into operation without a soft start, it can cause an electrical shock due to high voltage spikes. A soft start helps guard against this by slowly bringing the power to the motor in a managed way rather than causing a sudden surge. As well as decreasing the risk of electrical shock, controlling speed and torque also reduces vibrations during startup, which helps prevent damage to other components.

Overall, soft starts present many attractive advantages that can lead to lower maintenance costs and increased safety levels while operating machinery in potentially dangerous environments. However, there are some minimal cons such as additional wiring requirements or cost – but these could be outweighed by the large benefits of reduced downtime and enhanced safety measures offered by a soft start installation.

In conclusion, the advantages of using a soft start are undeniable. The next section will explore how these advantages benefit us when dealing with potentially hazardous situations: reduced electrical shock.

Reduced Electrical Shock

Soft starting motors provide a range of benefits to businesses and electrical items across various industries due to its ability to reduce the electricity flow applied when powering up. In the case of electric motors, when running a motor usually requires the full voltage of power, where the risk of electrical shock or electrocution is high. Soft starts are designed to “phase in” the start up current by reducing it from full power to partial power instead, allowing users to limit their exposure to potentially hazardous voltage levels.

The undeniable advantage of this type of system is that it can save lives by preventing dangerous electrical accidents. However, on the other hand, some argue that such systems may create additional risks, as they have the potential to create hot spots within wiring and equipment that aren’t typically seen with systems which require higher power rating. Despite this point, the concentration of force that these systems require still remains significantly lower than those powered traditionally.

Overall, soft starting motors bring a wide variety of benefits, with the reduction in potential electrical shocks being chief among them. By reducing the risk for all manner of users, using these systems for everyday motor control applications becomes a far safer experience. Moving forward, we will now explore how soft starters can ultimately reduce wear and tear on both the motor itself and its associated parts.

  • Soft starters provide protection from electrical damage, by preventing high inrush current and voltage fluctuations.
  • A study in 2017 found that soft starters reduce energy consumption on average by 12%.
  • According to Industry Canada, the efficient use of soft starters can provide between 15 and 20% savings in energy consumption.

Essential Summary Points

Soft starting motors offer a range of advantages to businesses and electrical items in various industries. Their main purpose is to reduce the electricity flow applied when powering up, limiting the risk of electrocution or shock. This technology can also decrease wear and tear on motors and their associated parts. While there may be potential risks with these systems, the force required is still significantly lower than other traditional methods.

Decreased Wear and Tear

When it comes to motor starting, soft starts have seen great success in minimizing wear and tear on the motor. Operators of motors not using soft starts may notice more mechanical failures due to sudden and dramatic spikes in current draw when the motor starts up, causing extra wear and tear on components of the motor and drivetrain system. Soft start systems level out current and voltage during that startup stage, resulting in less strain on the motor’s current rating and helping to avoid or delay premature mechanical losses.

This is especially important for applications in which motors are shut off regularly; this process of sudden shutdowns can cause a great deal of wear on a motor. A wide range of users can benefit from soft start applications, such as material handling, pulp and paper mills, or agricultural equipment where these repetitive shutdowns are common. This will help reduce operating costs due to replacement parts, allowing for savings over time that otherwise would not have been possible without the use of a soft start system.

In other cases, however, some motor-operating conditions can be improved by direct-on line operations with no starting features. In those circumstances, hard (direct-on) starting without any dampening features may actually produce better results than soft starts. It is essential to test both scenarios thoroughly before settling on any particular approach for a specific application.

Either way, when taken as a whole, decreased wear and tear associated with using a soft start system greatly outweigh any other drawbacks. By properly regulating voltage during start up and shut down periods of operation, motors do not see extreme electrical forces that can otherwise cause rapid component failure or require frequent maintenance and shutdowns for repair work. With this in mind, the next section will explore the different applications that typically use soft start systems.

Applications of Soft Starts

Soft Starts can be applied to a variety of industrial processes ranging from conveyor systems, pumps and fans, compressors and electric motors. Each of these applications involve high torque loads that require electric motors for increased performance. The most important application for soft starts is when the need exists to bring the motor up to full speed slowly over time. This prevents current overloading which conserves energy as well as protecting both the motor and the circuitry associated with it. In addition, this also helps to reduce wear on mechanical components, gears and belts that are connected to the motor.

Also, in many situations, a soft start may be required due to noise or vibration considerations; in these cases the use of a soft start slows down the rapid acceleration which reduces the amount of vibration and noise. However this is not always true as depending on which type of soft start is used there may still be some level of noise produced by the implementation.

Aside from these applications, another viable application for soft starter circuits are for attaching devices to electric motors. This may include things such as emergency stops that can be employed during certain circumstances such as an emergency power outage or other hazardous situation where it is essential to ensure the load has been shut down safely.

These applications demonstrate clearly that when given necessary environmental conditions soft starters can offer several advantages for both safety and efficiency. That being said it is important to take into account any potential drawbacks associated with implementing a soft start; whether that is a decrease in speed or amplitude due to an inadequate size being chosen, time delay related issues when setting up speeds and ramp times, or even additional cost linked with purchasing these starters larger than what would otherwise be needed normally if running at full voltage and frequency right away.

In conclusion, if needed conditions are present then utilizing a Soft Start system can yield great benefits by providing increased safety protection and operational efficiency gains whilst reducing maintenance costs associated with wear and tear on machine components due to rapid acceleration. At this point it is time to move on to look more closely at motors themselves in order to determine which type of motor will best suit our needs when considering the implementation of a Soft Start solution.


Motors play an integral role in many industrial processes, from conveying materials to operating machinery. They are used in a variety of applications, and their effectiveness can be impacted by the method of start. There are two primary types of starting motor approaches: hard start, which turns the motor on abruptly and quickly, and soft start, where the power is gradually ramped up to avoid high starting current or torque. Each of these approaches has its own advantages and disadvantages, depending on the specific type of motor and application.

Advocates of hard starting motors point to their reliability and ability to reach maximum speed quickly, providing more accuracy in applications requiring precise RPMs. They also require less power than soft starting, making them more energy efficient in some instances. Critics argue that hard starts can be damaging to motors due to large currents associated with the sudden activation of the electrical field. This can not only shorten the life expectancy of a motor, but it can potentially cause costly damage due to mechanical stress resulting from vibrations created by rapid acceleration.

On the other hand, proponents of using soft starts note that they reduce peak current draw by slowly increasing voltage until maximum power is achieved. This minimizes mechanical stress as well as noise emissions from complex machinery. In addition, increased efficiency in low load conditions results in lower system input costs for facilities operating multiple motors over long periods of time. Soft start detractors maintain that there can be issues with accuracy since extra time is required for target speeds to be reached and increases minimal losses associated with their use.

In conclusion, both hard start and soft start approaches have their benefits which must be weighed against potential drawbacks when selecting an appropriate starting motor approach for an application. Moving forward in this article will explore further into one such approach – soft start – including its benefits and considerations when implementing it within electrical equipment systems.

Electrical Equipment

When it comes to electrical equipment, a soft start is an important device for ensuring the system runs efficiently and safely. It helps to reduce incoming voltage from high levels to more manageable levels, allowing motors to operate more effectively and at lower temperatures. This can have a number of positive effects on the machines and on their associated components.

On the one hand, soft starting motors can extend the life of the equipment due to lower operating temperatures. By allowing the motor’s starting current to gradually increase over time, the sudden spike in voltage that would otherwise cause increased heat and strain is avoided. This leads to less wear and tear on the motor, resulting in fewer maintenance issues and longer life. Additionally, soft starting motors use less energy overall as they do not require large amounts of electricity when first starting up.

On the other hand, some mechanical systems may require higher concentrations of torque power or speed than what soft starts provide. In these cases, there may be a trade-off between protection of the motor or protection of the system itself – while using a soft start would help protect one component, it could potentially limit performance in another area. Furthermore, some equipment may be too sensitive for a soft start mechanism as well.

In any case, careful consideration should be taken when selecting appropriate electrical equipment as its life greatly depends on proper installation and correct configuration. The next section explores how soft starts are used to control motors so that all components of a system stay safe and operate optimally for years to come.

Controlling Soft Starts

Controlling soft starts can be achieved through different types of controllers. Soft-start controllers allow gradual increases in motor speed using a combination of ramp-up times and current limiting techniques. This offers several advantages including reduced torque pulsations, improved motor life, stable startup performance, and safe operation without tripping breakers or overload relays.

In contrast, some argue that soft starting motors can lead to poor performance if not done correctly. Forcing an increase in speed too quickly can result in large transient overvoltage spikes, leading to damage of the windings and capacitors. Improper soft start settings may also cause an acceleration that is too slow, resulting in prolonged warm up times which can reduce the efficiency of the motor.

To ensure proper operation and extend the life of the motor, it is essential for users to choose the correct soft start controller and ensure that its parameters are accurately set. The correct settings will depend on a variety of factors such as system voltage, load type, and other environmental conditions.

Incorporating a well-designed soft start into systems with AC induction motors has become increasingly necessary as motors become larger and more complex. With the right software and hardware, businesses can benefit from improved operating efficiency while avoiding the costly downtime associated with sudden motor failure.

Leading into the next section: Now that we have discussed controlling soft starts, let’s explore how they compare against other starting systems such as direct on line starters and variable frequency drives.

Soft Start vs. Other Start Systems

When selecting the best start system for a motor, there are several different options available, of which Soft Start is one. Other start systems, such as Direct On Line (DOL) start systems, Reduced Voltage Starters (RVS), and Variable Speed Drives (VSDs) are alternatives available for smooth starting of a motor but all primarily start based on the power of the current. DOL starters involve the direct connection from an AC power supply to the motor windings and the RVS reduces the voltage delivered to the motor in two stages. However, when compared to Soft Starts, these have higher energy usage and can cause additional wear and tear on a motor. VSDs also require high-end electronics and skilled engineering knowledge to operate, take up more space and have higher installation costs compared to Soft Starts.

Overall Soft Starts are typically preferred because they contain sophisticated electronics that allow them to control output voltage and current in order to reduce electrical stress on the motor windings. This produces a much smoother start than conventional starter systems, reducing energy use, wear and tear on motors, and improving overall system performance and reliability. The next section will assess the conclusion of this debate by exploring this benefit further.



Soft starting motors offer a number of potential benefits over conventional starting motors, making them an attractive choice for many applications. Soft starters can reduce the initial inrush of current that can occur while starting a motor, minimizing electrical system stress and potentially saving money on electricity costs. They can also provide smoother acceleration and deceleration, eliminating sudden torque changes and reducing wear-and-tear on the motor and other mechanical components. Additionally, soft starters may offer better safety features compared to other types of motor controllers.

While some experts caution against choosing a soft starter simply because it is cheaper or easier to install than other motor control alternatives, the cost savings provided by energy efficiency and wear-reduction should be weighed with care before deciding which type of motor controller will best suit an application. As with all decisions regarding power systems, it’s important that safety and reliability are maximized to ensure optimal operation and longevity. Soft starters provide a viable solution for many applications and engineers should consider their pros and cons before making a final decision.

Frequently Asked Questions

How does a soft start differ from a regular start?

A soft start is a type of motor start that uses reduced voltage and current to slowly ramp up the motor speed, as opposed to going from zero to full load in one go. This process reduces stress on the electrical circuit and allows for more precise performance. Soft starts also help protect against inrush currents which can cause instability, damage to equipment, or premature failure of components such as fuses or contactors. The slower acceleration helps reduce wear on the motor and its components, resulting in longer life expectancy and less maintenance. Additionally, it can help increase energy efficiency by allowing a motor to run closer to its rated efficiency even during transients.

What are the advantages of using a soft start system?

The advantages of using a soft start system are numerous. For starters, they help reduce stress on motors and the electrical grid, resulting in improved efficiency, higher levels of safety, and reduced energy consumption. Furthermore, because of the gradual increase in motor speed during start-up when using a soft start system, it minimizes wear on mechanical components, leading to a longer life for these motors. In addition, by decreasing the inrush current that is typical on motor starts, these systems also improve power quality for the entire electrical system. Lastly, these systems also enable users to control motor speeds more effectively, which allows operations to be more precise and consistent.

Are there any safety considerations that need to be taken into account when using a soft start system?

Yes, there are important safety considerations to take into account when using a soft start system. The first consideration is electrical safety. Soft start systems allow motors to start gradually under load, which can generate greater electrical loads than starting without a soft start system. Overheating and arcing of circuit components can be the result if appropriate electrical protections are not installed. Additionally, it is important to pay attention to the motor starting current settings, to ensure the motor does not exceed its rated amperage during a startup procedure.

It is also important to note that any mechanical brakes utilized in combination with soft start system must be rated for the higher initial torque generated by the soft start. If brakes are not designed properly they may become locked and potentially cause an overvoltage or overcurrent situation. Failure to adhere to these considerations can result in severe damage or injury.