Variable Frequency Drive vs Soft Starter - All You Need To Know

What is a VFD?

A Variable Frequency Drive picks its name from its key role. These appliances are commonly utilised for running an AC motor at variable speeds or even allow them to raise their speed to propel them with a smooth startup.

What is a Soft Starter?

Since Electric Servo Motors in most cases mandate the need of large amounts of electricity when they accelerate to nominal speed, a Soft Starter is often utilised in order to limit the surge of current known as “inrush current” in addition to the torque of the electric motors, which leads to a safer, smoother, and gradual start-up.

So what are the key differences between a VFD and a Soft Starter?

Speed - 

If your application really requires a large inrush of current but does not need speed control, then a soft starter is an ideal option in comparison to variable speed drives.  If speed control is an important element, then a variable frequency drive is a must.

Price - 

In the modern world, we operate in now - especially in the case of manufacturing and manufacturing purposes, price is an important consideration. Since soft starters have comparatively fewer features and characteristics, it is priced at a lower price in comparison to a variable frequency drive.

Size - 

Finally, the last parameter, if the size of your device is a point of consideration for you, soft starters are smaller than most of the VFDs. So if you have a lack of space, a soft starter would be a better option.

We can even evaluate different applications of these motor starters to further comprehend the differences between the two - 

Water Treatment Facilities

A water treatment plant commonly has a steady flow of water entering the plant. Let us assume that the demand for water flowing out of the plant is constant with the supply entering the plant. In this situation, a soft starter would be a better option since when using the water pump there would be an inrush of current on the motor that the soft starter could handle.

Conversely, the need for water exiting the plant varies, we would want to alter the speed as well, which makes the VFD a better choice for the application.

Cooling Fan System 

In conventional cooling fan systems, a cooling fan turns on when the plant air temperature hits a high-temperature set-point. Once the set-point is equalled, the cooling fan will reduce its operation to sustain the air temperature unless it falls below a low-temperature setpoint, where it consequently shut off. However, if the temperature continues to rise and crosses the high-temperature setpoint, the fan will again need to speed up. Over here it is clear that a VFD will be preferred.

#SchneiderElectric is an established brand in the fields of motor control (PLC’s included), power management, automation, and even electric protection. In addition to VFD and soft starters, the motor pump range of products is also top-quality.

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