Leveraging the Versatility of the VFDs for Optimal System Performance
Water- and air-handling system professionals are often faced with a common end user concern: how to maximize a system’s performance while minimizing maintenance, disruptions and operating costs. Today, there is an added challenge to ensure the system is efficient, which can add up to significant savings for users across various industries and applications. But those savings must come without adding downtime costs and must also be easy and intuitive for users to set up and utilize.
Enter variable frequency drives (VFDs). A VFD will run a pump’s motor to meet the demands of the application, contributing to reduced energy costs. The latest VFD options are designed for more than just commercial applications; they can also provide incredible benefits and application-based solutions for engineered projects across a variety of industries including mining and construction, heating, ventilation and air conditioning (HVAC) operation and agricultural settings. Field demands are driving engineering enhancements, making drives more user-friendly for easier programming. Today’s VFDs deliver benefits related to performance, maintenance and system protection without a costly learning curve.
The key to using VFDs for optimum efficiency is specifying a system that maximizes each application’s unique performance needs. From customized options to off-the-shelf platforms, VFDs have come a long way in terms of versatility. They offer features that are important to water- and air-handling system professionals, including setup and control options that are intuitive to use. Here are a few ways users can maximize the versatility of VFDs:
Optimize the System for Variable Demand
System needs are never a one-size-fits-all equation, especially when it comes to water or wastewater management. Even a single application can have different needs at different times. For example, in the water industry, VFDs can ensure a pumping system is smart enough to deliver the variable demand needed across an operation. As water demand increases or decreases, a VFD will instantly adjust the motor to the proper speed, ensuring the water pressure stays constant. This can be especially important in applications like irrigation. VFDs can optimize an irrigation system to deliver constant pressure with varying flow requirements and water levels, allowing operators to dial in the ideal pressure required to operate nozzles for what is best for the application—whether the user is growing crops or maintaining a golf course. This constant pressure delivery assures the right amount of water covers a property without gaps to maintain the consistency that is needed.
VFDs can also deliver benefits in terms of easy and cost-effective scalability. One illustration of this is a school in Michigan that needed to update their aging water pumping system as part of an expansion plan. They wanted a solution that could grow with the school, meet changing demands and limit system downtime. The engineers selected a duplex constant pressure water system that included two VFDs paired with two new submersible turbines. This system helped optimize operation to meet water supply demands during critical in-class hours. With more construction and renovation anticipated over the next several years, the system’s scalability provides room for expansion since its platform enables built-in lead/lag and alternation capacity for multiple drives. Over the long run, this design also mitigated heat exposure on the system, preventing rapid cycling and helping to alleviate future expenses related to service costs and downtime.
Take Advantage of Application-Based Presets
VFDs can be as complex or as simple as needed for the user and application—from general purpose to application-specific. Some of today’s newest VFDs allow users to select from presets in seconds with readily available industry standards supporting various load requirements. In the pumping industry, VFDs can address the unique system dynamics of each type of pumping system, such as submersible, centrifugal and circulating pumps. In other markets, presets can address HVAC applications for cooling towers, supply fans and exhaust fans. Constant torque applications presets can support the usage required in compressors as well as mining settings.
Application-based VFDs are designed for quick programming and operation, with easy-to-navigate on-screen displays, analog switches or companion apps that alleviate learning curves and increase technology adoption. These features can include presets that offer a guided step-by-step setup for basic or advanced parameters. For applications with multiple drives, installers can create and manage templates to load configurations across an operation, boosting productivity.
Customize to Site Parameters
In addition to customizing a VFD to an application, users can also customize it to their site and the unique environmental needs of their operation. Will the unit be housed outside in harsh conditions? How large or portable is the system it is supporting? How small does the unit’s footprint need to be? Select applications might require drives supporting phase conversion to allow for single-phase voltage (in addition to three-phase voltage) to service jobsites where three-phase voltage is not readily available.
For large pumping systems, VFDs have historically been engineered to be permanently affixed to a structure. Now users have different needs, including pumping system applications that require VFDs capable of delivering significant power while having the mobility to address jobsite demands. These mobile VFDs must not only be portable, but also durable under harsh outdoor conditions. Available as a self-contained unit or a pump panel configuration, today’s VFDs can be rated for outdoor use, reducing the effect of environmental hazards or the need to construct separate outbuildings.
Some VFDs have also increased their power density, making the units smaller in size. Thanks to advancements in technology, VFD microcontrollers have become more compact, allowing more features to fit into the drive without increasing the cost or creating a bulky unit. This can be especially helpful in HVAC settings, where mechanical room real estate is at a minimum.
Take Advantage of Maintenance, Servicing & Troubleshooting Support
In addition to helping with setup, optional telemetry controls—combined with VFD companion apps—allow users to control the system remotely and compile data using a smartphone or computer. This can help enhance on-site maintenance or remote troubleshooting. Built-in logs help professionals pinpoint specific faults, access local monitoring and view logs and reporting in order to streamline troubleshooting and help with remote oversight of the system if personnel are not on-site.
Consider a mine site where operators are spread thin across many miles. Could they benefit from remote troubleshooting or service alarms that send through push notifications to their phone? If VFDs are used to control HVAC equipment, additional template settings or safety protocols can help maintenance personnel program and manage a variety of equipment across several properties. VFDs can help these busy crews leverage technology and maximize safety without requiring proximity to the drive.
Utilize System Protection Features
A pumping or air-handling system is an investment, and VFDs help protect it. When evaluating a VFD, consider options that offer built-in features designed to extend the life of the overall system for hydraulic or electrical conditions. For hydraulic conditions, these protections can include underload, overload and broken pipe detection. When it comes to electrical conditions, VFDs can protect against low line voltage and provide overcurrent protection for the motor.
For example: Does the VFD include trip indicators that are easy to read? If users have concerns about the water level of the well potentially running dry, does the VFD offer programmable low water level settings to dial in the trip points? This protection feature also allows programmable recovery time, giving water levels time to recover and reducing the harmful effects of surging the well.
Among the many benefits of current VFDs, the overall protection of the system during normal operation is perhaps the most important. By delivering advanced speed controls and soft start features that maximize a pumping system’s life, a VFD helps reduce system maintenance costs—essentially running at maximum efficiency. This benefits owners and operators in terms of energy cost savings, ease of installation, increased performance and streamlined maintenance.