Motor Controls: VFD vs. Soft-Start

Both Variable Frequency Drives and Soft Starters are viable choices to control electric motors. When choosing between the two options, it is highly recommended to consider your application requirements. Soft starters offer a cost-effective solution to reduce inrush current during initial motor startup. VFDs offer more versatile and advanced control capabilities to unlock advantages worth consideration.‍

Reasons to consider utilizing VFDs in your system

• Precision Speed Control: VFDs by design allow for variable speed control of electric motors, enabling technicians to fine-tune motor performance based on specific conditions and provide the ability to run a motor above designed speed, limited by the mechanical constraints of the motor. When implemented correctly, this can result in more efficient energy consumption, better control of processes, and less wear and tear on equipment. 
• Monitoring Capabilities: VFDs have the capabilities to not only control but also monitor a motor’s speed. Some available VFDs have the capability to utilize ADC or Automatic Device Configuration. ADC allows automated configuration parameters if you must replace a drive, reducing downtime.
• Energy Efficiency: VFDs enable efficiency in applications that require variable speed control, such as pumps, fans and conveyors. VFDs allow adjustment of the motor speed to match actual demand, which over time can significantly reduce energy consumption and lead to lower operational costs. 
• Reduced Mechanical Stress: VFDs can provide smoother start-up and controlled deceleration, translating into less shock to components in your system. Gears, belts and bearings will all benefit from the smooth operation of a VFD control.
• Optimized Process Control: Integrating a VFD into a system may provide more advanced control options like torque control, programmable settings and communication with other components in automation systems. These features may enable better complete process optimization, consistency and safety. 
  

Soft Starts are the right choice for the right application

For applications that do not require all the bells and whistles, soft starts are a dependable, reliable solution in the correct application. When choosing between a VFD versus a traditional soft start, the system requirements, project budget, and operational complexity should be evaluated. If the system requires motor monitoring, precise speed or stop control, or energy efficiency, a VFD may be a clear choice to integrate into your system. By contrast, a soft start will only limit the voltage during startup, and it does not offer continuous speed control. For applications with less complex requirements, such as a hydraulic power unit, a soft start could be the right fit. 

The experts at Embry Automation & Controls have the experience to help you determine the best solution for your specific operations. We will review the processes involved and work with your team to provide a system that provides efficiency, performance and reliability. For more information and to discuss how we can help improve your operations, contact us today. 

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