A variable frequency drive, or VFD, is an adjustable-speed drive that can control AC motor speed and torque by varying motor input frequency and voltage. These drives are used in a number of applications, including irrigation, horizontal surface pumps, saltwater disposal, transfer pumps, and centrifugal pumping. AID solutions combine the strength of optimized control with VFDs, allowing pump users to reduce energy costs, improve performance, and extend equipment life.
Selecting a VFD
Although variable frequency drives are frequently used in the pump industry, it is essential to properly match a VFD to each unique pumping application in order to create an efficient, reliable system. In simplest terms, a VFD first converts AC power to DC, and then this signal is inverted back to AC through pulse width modulation (PWM). Using the right-sized VFD will save money and increase energy efficiency, but there are a number of variables to consider. The key ratings to note when sizing a VFD for a given motor are Full Load Amps (FLA), horsepower, voltage, RPM, and whether the motor is inverter duty rated. Full Load Amps, rather than horsepower, is the critical piece of motor information to use when sizing a VFD. For example, if a VFD is capable of 250 amps and the FLA of the motor is 246 amps, the next larger size VFD should be used instead.
The Benefits of VFDs
Motors associated with pumps tend to be sized for peak loads, not necessarily for normal continuous operation. The primary advantage offered by a VFD is that it matches the energy required for a given load on a motor, thereby increasing efficiency, saving energy, and reducing costs. This is significant because on average, 85 percent of a pump’s life cycle cost is attributed to its energy consumption. Secondly, unlike other ways of controlling the operating point of a pump, such as a throttling valve, a VFD controls flow with no additional restriction to the piping system. Plus, the level of control and responsiveness of a VFD in comparison to mechanical means of limiting flow is tremendous. Next, VFDs provide a gradual and smooth ramping up of the motor, significantly reducing maintenance and repair costs, decreasing wear on impellers and other components throughout a pumping system, and greatly extending the life of the motor and the pump. Finally, since VFDs allow operation of the motor at less than full load, wear and tear on bearings, seals, and other wear components are greatly reduced as well, and less maintenance and repairs are required.
AID has Automated Solutions for Every Pumping Application
Advanced Industrial Devices automation solutions, including VFDs, are available for most pumping needs. The PumpMaster™ VFD is flexible, adaptable, and easy to customize. This variable frequency drive system is easily programmable and gives users the ability to control operational speeds of driven equipment all from one panel. The OptiPump™HPS VFD is designed specifically for saltwater disposal applications. This horizontal surface pump control system allows better control and monitoring of tank levels, thrust chamber oil level, vibration, suction pressure, pump speed, and discharge pressure and automates the control of the throttle valve, keeping the pump in the preferred operating range.
At AID, our team of experienced professionals is focused on meeting our customers’ needs by getting them the right solutions quickly. We’re committed to providing you with a custom solution that is simple to operate, improves efficiency and reliability, and reduces operating costs.
To find out more, contact our customer service team.