Motor efficiency standards

Electric motor efficiency standards established by the U.S. Energy Independence and Security Act of 2007, the International Electrotechnical Commission (IEC) in 2008 and the European Commission Eco-design Regulatory Committee in 2009 motivated motor manufacturers to increase performance and efficiency, reduce energy consumption, and minimize greenhouse gas emissions.

Efficiency targets: Europe’s IE3 minimum-efficiency standard for new electric motors, while not mandatory until 2015, is comparable to the current U.S. NEMA Premium standard. Premium-efficient motors developed by Baldor in recent years comply with both standards. The Super-E Metric IE3 AC motors are available in 22 power ratings, from 4 kW to 375 kW, with three speed options at each rating. Maximum efficiencies at full load range from 89.9% to 96.3%, enabling significant energy cost savings. Constructed with durable, cast-iron IEC frame types and wound with Baldor’s inverter spike-resistant (ISR) magnet wire, the motors are considered “inverter ready” and as much as 100 times more resistant to transient voltage spikes, short rise-time pulses and high frequencies. Improved insulation materials are said to withstand peak voltages to 1,600 V.

Exceeding standards: Some manufacturers are moving beyond the minimum NEMA and IEC standards. For instance, Siemens Energy & Automation recently introduced its compact SH630 Above NEMA AC induction motor with features, designs and materials that meet or exceed industry standards. Part of the H-compact Plus series, the SH630 produces as much as 11,000 hp at supply voltages to 13.8 kV at 60 Hertz. Its low-windage design and precision components minimize friction losses. The Siemens Micalastic vacuum-impregnated insulation system lengthens the motor’s service life by ensuring thermal stability, surge strength and resistance to severe operating conditions.

NASA-inspired approach: Cleantech companies concentrate on solutions designed for environmental sustainability. One such company is Power Efficiency Corp., whose E-Save motor efficiency technology blends work by NASA with the company’s patented and patent-pending technologies. The 3-Phase Motor Efficiency Controller (MEC) product line, now rated for IP00 and IP65/NEMA 4X, uses the E-Save platform that dynamically optimizes the efficiency of large industrial electric motors operating at a constant speed, and under variable or light loads. It senses the phase lag between current and voltage and adapts the energy being fed to the motor accordingly. Because less electricity is consumed, CO2 emissions from electricity production are reduced.

Three new 3-Phase MEC frames enable energy savings for AC induction motors rated to 300 hp. The UL-certified frames are controlled by a high-performance digital signature processor (DSP) using proprietary algorithms. The solid-state motor controller has soft starting and electronic motor-protection features. An optional Ethernet interface and upgraded MECAssistant motor control software offer the potential to share real-time, wired or wireless information regarding energy, emissions and motor diagnostics over the Internet.

Greater torque: For applications requiring higher efficiency, variable speed and no maintenance, a line of high-torque, variable-speed gearmotors is available. Bison Gear & Engineering Corp. increased the output torque capability of its Verdant Duty 3-phase AC gearmotors by seven times with its new 650 Series Verdant Duty AC gearmotors. The variable-speed, inverter-duty gearmotors are constructed for long-life operation, and continuous-duty torque outputs from 148 to 717 in-lbs. Matching AC drives in NEMA 4X enclosures are available.

Pollution-free design: Zero-emission systems are moving us toward the goal of energy independence. A lightweight electric motor developed at Oxford University’s Department of Engineering Science shows promise for more efficient, high-performance electric vehicles, along with aerospace, renewable and industrial applications that require improved power-to-weight performance and compact electric drive systems. Oxford Yasa Motors, a spin-off from the university, will commercialize the prototype into a range of commercial products.

Originally devised for the hydrogen powered 2008 Morgan lightweight, fuel-efficient car (LIFEcar), the motor was later configured in collaboration with Delta Motorsports for a new four-seat coupe. The materials and design of the yokeless and segmented armature (YASA) motor were optimized, including removing the gearbox to reduce weight, leaving the rotor as the only moving part. Weighing 23 kg, the new direct-drive motor reportedly requires half the volume and gives twice the torque for the same power output. It has a peak torque of 500 N-m and peak power of about 50 kW, which can be extended to approximately 75 kW.

E-mail Contributing Editor Sheila Kennedy, managing director of Additive Communications, at [email protected].