Snapshots: Motors and Drives
Danfoss announced the addition of the ETS 6 to the ETS series of electrically operated expansion valves. Designed to control liquid injection into evaporators, the new valve regulates refrigerant flow by offering a total of 480 steps from fully closed to fully open and ensures precise resolution for better control of superheat, even at low flow rates.
With the ability to adapt to a system’s exact capacity demands, the ETS 6 improves energy efficiency in refrigeration, heat pumps, and air conditioning systems. The ETS 6 is compatible with all common refrigerants, including R-410A, R-407C, R-404A, and R-134a. Compact and lightweight, the new valve can also be used in heat pump systems with bi-flow operation and joins a line of valves that covers the entire range of valve capacities.
Electro Static Technology
Variable frequency drives (VFDs) hold the promise of sizable energy savings, but need effective, long-term bearing protection such as the maintenance-free Aegis™ SGR bearing protection ring, manufactured by Electro Static Technology (EST).
According to EST, those savings could be wiped out by high maintenance costs. “If harmful voltage levels are identified, the installation of an Aegis™ SGR extends motor life by diverting shaft currents safely to ground, thus ensuring the reliable, long-term operation of the VFD-driven motor system and locking in energy savings to make the system sustainable and truly green,” said EST’s Adam Willwerth.
“Without mitigation, VFD-induced voltages can repeatedly build up on the motor shaft to a certain threshold, then discharge in short bursts along the path of least resistance, which all too often runs through the motor’s bearings,” he said.
“The discharge rate tends to increase with carrier frequency, but continued discharges result in the pitting of the ball bearings and race walls through electrical discharge machining (EDM). Concentrated pitting at regular intervals along the race wall can cause washboard-like ridges called fluting, a source of vibration and noise. By the time such damage can be heard, bearing failure is often imminent.”
An Aegis™ shaft voltage test kit measures and documents damaging VFD-induced voltages while there is still time to head off bearing damage and equipment downtime. The kit includes a special replaceable probe tip for accurate voltage readings on rotating equipment.
Emerson Climate Technologies
According to Emerson Climate Technologies Inc., the manufacturer has developed a “breakthrough” in comfort and energy savings with the Copeland Scroll® variable speed compressor. Designed for high-efficiency heat pump and air conditioning systems, Emerson’s new variable speed compressor allows heat pumps to achieve 13 HSPF and 20-plus SEER efficiency, 40 percent greater year-round energy savings than standard heat pumps.
With the Copeland Scroll variable speed compressor, systems can deliver significant improvement in year-round comfort for homeowners. By maintaining capacity at low ambient temperatures, systems equipped with Copeland Scroll variable speed deliver hotter supply air, a key need for heat pumps. In addition, summer humidity control is significantly improved with up to 60 percent capacity reduction. The Copeland Scroll variable speed compressor also provides diagnostics and protection capabilities to improve ease of service and system reliability.
“Increasingly, homeowners are looking to invest in energy-efficient HVAC systems,” said John Schneider, vice president of variable speed, Air Conditioning division, Emerson Climate Technologies.
“In a survey we conducted last year, 57 percent of consumers listed energy savings as their top priority in purchasing a system — over price. Our new variable speed compressor offers breakthrough efficiency for superior year-round energy savings potential. In addition, the top-ranked need for an improved heat pump is hotter supply air. With 60 percent overspeed capability, Copeland Scroll variable speed is a breakthrough in heat pump comfort.”
The Eon motor is the Genteq flagship in residential HVAC furnaces and air handlers, commercial variable air volume systems, and fan filter units. Eon is a lighter, more compact variable speed electronically commutated motor (ECM) that is backward compatible with the existing ECM 2.3 motor and fits easily into existing systems. Using the latest version of ECM Toolbox™, OEM customers can easily create Eon programs from existing ECM 2.3 motor programs utilizing the latest Windows-based software.
Genteq has improved the reliability of this motor with a fully potted single control board, additional transient protection (6 kV), improved I/O protection and state-of-the-art electronic components. Plus, the onboard memory (BlakBox) allows OEMs and contractors to monitor real-time performance and provides insight into the operation of the motor to maintain peak efficiency. Applications for the EON include:
• Residential HVAC furnace and air handler,
• Commercial variable air volume (VAV), and
• Fan filter units (FFU).
NovaTorque Inc. manufactures high-efficiency, cost-effective, interior permanent magnet motors and recently introduced its next generation design of 3-hp and 5-hp Premium Plus+™ motors.
According to the manufacturer, the motors boast a nominal efficiency of 93 percent and 92 percent respectively. In addition to having higher efficiency at the rating point, NovaTorque’s PremiumPlus+™ maintains high efficiency over a wide speed and load range. As an example, in a variable-speed, variable-torque application such as a fan or pump, a 50 percent reduction in speed results in an 87.5 percent reduction in load. According to NovaTorque, its motors will “maintain an efficiency of approximately 90 percent.”
NovaTorque motors are compatible with readily available standard model VFDs from most leading manufacturers. They are typically applied to variable speed applications (fans, blowers, pumps, compressors, conveyors, mixers, grinders, etc.) using the back EMF (electromotive force) of the motor for commutation. They may, however, also be used in closed loop servo mode, best applied in high inertia load applications, matching their relatively high rotor inertia.
Publication date: 01/16/2012