‘Re-invented’ fan motor cuts energy use by up to 80%
A US company claims to have developed a new class of high-efficiency motor that that can cut energy consumption by up to 80%, while improving power quality. Missouri-based QM Power says that its Q-Sync smart synchronous motor – aimed initially at refrigeration fan applications – will also improve reliability and allow energy-saving retrofits at a similar cost to conventional motors. QM is planning to expand the technology into other applications.
The company’s claims have been backed by the US Department of Energy (DOE), which has helped to fund the development and testing of the motor and has issued a report describing it as a “high-impact technology”. On the basis of one field trial, the DOE calculates that retrofitting the new motors to refrigeration and HVAC system across the US could save the nation around 300TWh a year.
“Motors can consume up to 70% of all the energy used in commercial buildings, but amazingly there has been little-to-no innovation in motor efficiency over the past half-century,” says QM Power’s co-founder, president and CEO, PJ Piper. “With Q-Sync, we’ve reinvented the fan motor to exceed modern-day energy and environmental requirements, deliver bold new energy savings opportunities and dramatically reduce grid congestion. The motor can now be the next meaningful retrofit and OEM opportunity for energy savings in commercial buildings.”
Until now, the commercial refrigeration industry has had two main choices for fan motors: induction, or shaded-pole, motors, developed in the 1880s, which account for more than 65% of all commercial refrigeration motors in the US and are only 20% efficient; and electronically-commutated motors (ECMs), developed in the 1960s, which currently have a 35% market share and are about 60% efficient.
The new Q-Sync motor has a claimed efficiency of 75% and is similar in cost to an ECM. At the heart of the patent-pending design is a simpler, smarter controller.
Conventional ECM motors require continual conversion between AC and DC power. By contrast, once the new motor reaches its operating speed, it shifts to AC power direct from the grid, eliminating the need for continuous power conversion. And its permanent magnet design eliminates the additional energy requirements and slip associated with shaded-pole motors. The result is a motor that is said to provide a reduction in energy consumption of up to 80%, both at the meter and at the grid.
The technology is based on a split-wound stator coil and a controller that uses a Hall effect sensor to detect the rotor position. At start-up, or when the sensor detects that the motor is not running at synchronous speed, the controller varies the frequency of the current delivered to the stator coil to bring the motor up to synchronous speed. When the frequency is the same as the input and the motor is running synchronously, the controller is switched off until either the motor falls out of synch, or is stopped and restarted. If the motor falls below the synchronous speed, the controller adjusts the motor timing as it does at start-up.