Water and wastewater treatment plants routinely install variable-frequency drives (VFDs) to improve energy efficiency in equipment. Now a new family of VFDs has entered the market, with the capability to provide actionable data that helps users make sound decisions affecting maintenance, energy consumption and overall cost of ownership.

Schneider Electric offers the Altivar Process family, which the company calls the first line of variable-speed drives with embedded intelligent services. They are available in ratings from 1 hp to 1,500 hp. Targeted for water and wastewater, oil and gas, food and beverage, and other process industries, the drives are designed to go beyond traditional motor control to help users optimize business and process performance.

Through condition monitoring, the drives help ensure that applications perform at optimum efficiency. They use embedded process knowledge, configurable onboard dashboards and a graphical display to deliver information tailored to the user’s application. Jeff Szwec, product application engineer for AC drives and soft starts with Schneider Electric, talked about the product line in an interview with Treatment Plant Operator.

TPO: What is the unique essential benefit of these new drives?

Szwec: The drives provide water and wastewater plant personnel with lots of opportunities to look at their total cost of ownership with respect to the operation of major energy-consuming equipment, such as pumps, blowers and fans. The technology provides unique views into the data and presents it in readily accessible and usable forms.

TPO: How do the drives help improve operations?

Szwec: Consider the overall process around a pump. The drives have multiple functions that users can configure. For example, some drives have a function called anti-jam, used to dislodge debris that can clog an impeller. The pump manufacturer can use this functionality to on occasion rotate the pump in reverse for a short time. Care must be taken not to implement this function on pumps that could be damaged by running in reverse. With the Altivar drives, the user can configure this feature.

The user can also look at conditions, such as how the pump is operating with respect to the level in a wet well level, so that it alerts personnel to a condition where the pump could run dry. Or maybe they’re concerned about filling a pipe too fast. If so, there’s a pipe fill function on startup. All these things can be configured with the drive.

TPO: How might the drives help a user improve energy efficiency?

Szwec: It helps users to know, for example, whether a pump is operating near the best efficiency point on its pump curve. The drive helps them see this because they’re able to enter the pump curve data from the manufacturer. A graphical representation of the pump curve appears right on the drive keypad. The information can lead them to ask, “Could we adjust the way we operate this pump to bring it closer to the most efficient operating point?” These drives also provide highly accurate motor power measurement capability, accurate to within 5 percent.

TPO: How easy is it to access information from the drive?

Szwec: Our drives have always generated data, but now we’re providing a better platform to get at the data. An embedded Web server allows users to connect to the drive wirelessly, look at the data and configure dashboards on a tablet or a smartphone. They can set up the dashboard with the parameters they want to watch for trending, so they can analyze what is going on with a particular application. Achilles Level 2 cybersecurity is built in.

TPO: How does the technology simplify functions like configuration and troubleshooting?

Szwec: The drives can dynamically generate quick-response (QR) codes that give users access to specific technical information about the drive by way of mobile devices. For example, a user looking to configure a parameter can scan the QR code with a smartphone and get access to help. If a fault occurs, the keypad turns from its normal gray-white color to red, easily identified by the user. Then the user can scan the QR code and bring up information on the nature of the fault, along with possible remedies. QR codes also provide instant access to support information and can help in contacting a customer care center.

TPO: Can data from the drives be accessed by way of a SCADA system?

Szwec: We have the ability to communicate via SCADA — all the data can be extracted. It’s configurable and scalable and can be accessed remotely.

TPO: Is data from the drives useful in optimizing maintenance?

Szwec: Maintenance makes up a large share of ongoing operation costs. Altivar Process drives help support condition-based maintenance, such that users don’t do maintenance more often than necessary, they don’t do it too late, they do it when it’s needed. Take a pump for example. The drive can provide and graph trend information about power usage over time. Perhaps that is suddenly climbing. Or the horsepower output is changing. Or the pump is operating at one extreme end of the pump curve or the other, which means a heavier load on the shaft and the bearings than if the pump were operating near the best efficiency point. These are indications that affect maintenance and therefore the total cost of ownership. 

TPO: What other advances are included with this drive family?

Szwec: A configurable sensorless flow estimation algorithm is included. There is also an advanced sleep/wake function that minimizes the energy consumed when a drive is in standby mode, waiting for a run signal. In addition, the circuit boards include conformal coatings to resist environments where hydrogen sulfide and other corrosive gases may be present.

TPO: How has the market reacted to this technology since its introduction?

Szwec: Water and wastewater facilities are trying to save money and operate more efficiently. They need the ability to look at their specific application and have data presented to them in a way that they can put their hands on it, analyze it and use it. This technology is an enabler. People we talk to see some significant operational advantages.