Digital variable reluctance technology could result in positive changes in the efficiency and power of pumps.
by Joel Latimer

Technology has reached the point where most of the world’s information can be accessed on a mobile phone within seconds. Answers to any questions are readily available at the click of a button, and tasks that once took days or months to accomplish can be done instantaneously. Why, then, are the vast majority of the motors used in manufacturing classified as “dumb”?

Though the motor is the most basic, integral component of the manufacturing industry, it relies on regular monitoring and human intelligence to determine how it is controlled. In the pump industry, improving efficiency, reliability and performance is vital. However, the limited capabilities of traditional motors have forced tradeoffs on these components—or required a price tag that is unrealistic for most users.

While variable speed motors have helped improve the current situation, variable switch reluctance motors can provide more flexibility in speed and function. What happens when a variable reluctance motor is equipped with smart sensing technology? Known as digital variable reluctance (DVR) motors, this technology has proven its efficacy throughout several manufacturing markets, and its applications are an excellent fit for the pumping industry.

How Does DVR Work?

DVR motors have a sensing capability based on temperature, vibration and bearing resistance. They are designed as three-phase motors but can operate on single-phase currents if there are any interruptions to the other phases or if there is a brownout.

Variable reluctance motors have a massive window of speed options, ranging from less than 100 revolutions per minute (rpm) to 100,000 rpm. Variable reluctance motors work without pulleys, belts or gears, limiting the need for constant maintenance and extending the motor's life. The only components of the motor are the rotor, stator and embedded micro-computer. The DVR motor is not considered by itself (in the way switched reluctance motors are) but as an integrated component and intelligent part of the device that transforms its application.

The motor eventually becomes an intelligent sensor, complete with a human machine interface (HMI) equipped with Wi-Fi and USB connectivity. The application of this solution in the pumping industry can help maximize output and performance without excessive cost. As a pump motor, it would monitor pressure for falls and spikes and would be capable of adjusting accordingly.

Switched reluctance motors have greatly impacted the manufacturing world, but implementing DVR control gives the body a brain. DVR comes at a perfect time, when further optimization in manufacturing is needed more than ever.

DVR for Pumps & Compressors

Though many consider the industry to be at a crossroads—in a tug-of-war between saving cash and generating technological progress—many may not realize that technology already exists that will improve operating efficiency in the pump and compressor industry.

Pumps and compressors demand highly efficient drives, often at speeds above the synchronous speeds available from conventional motors. A DVR drive can be easily implemented and can replace existing traditional motors—in exchange for an optimized, intelligent solution.

These drives can maintain high efficiency over the full operating range of most pumps and compressors. In some cases, the high operating speeds provided by DVR drives could enable the motor to be direct-coupled to the final application, removing the need for speed-increasing gears or belts and their associated setup and maintenance. Precise variable speed control eliminates the need for inefficient bypass systems and enables dramatic reductions in operating costs.

The pump in a home swimming pool, for example, will not only constantly analyze the water condition, but it could also calculate when the power will be at its lowest cost. This solution offers the functionality of a typical “dumb” motor while removing the complexity and high cost to the homeowner. The result is a remarkable improvement in both overall energy consumption and performance.

Enhanced Energy Efficiency

Electric motors consume about 65 percent of the electricity used in industrial processes. Regardless of the political landscape, companies can reap significant benefits from cleaner energy. DVR is a cost-saving technology that is designed to consume less electricity and equipped to operate at speeds appropriate to the application. By requiring less power to start the motor, DVR keeps electricity costs and consumption down.

Unlike many traditional motors, DVR motors are not designed with rare earth metals that increase their price tags. They are also lacking moving parts such as pulleys and gears that often require regular replacement. The smart components allow the motor to communicate to the user if it needs maintenance or if something has gone wrong in the pumping process. No guesswork is required—the motor can be designed to meet any specific needs.

The Future

The move from alternating-current (AC) or direct-current (DC) electric motors to a smart motor is comparable to the shift from a rotary phone to a smartphone. Currently, the electric motor world is dominated by inefficient and inflexible AC induction motors. Traditional motors require earth metals to be more efficient, but that requirement more than doubles consumer costs.

As energy demand continues to surpass supply and costs continue to rise, the solution is to implement motors that can meet and exceed the demand through efficiency and flexibility. A variable reluctance motor is an ideal replacement for the switched reluctance and traditional motors within the pumping industry, and can result in positive changes in the efficiency and power of pumps.