New and market-ready technologies for commercial and industrial settings
Recorded Tuesday, June 7, 2016 · 11am
- SPEAKER BIO(S)
Q&A from live broadcast:
Q: Can you explain how a VFD and MCASD work together or can you eliminate the VFD altogether and control it thru the building automation system?
A: When using a MCASD, the VFD is eliminated. The MCASD is controlled directly through the BAS.
Q: Is there a particular market space or application where we might expect to see faster adoption of PMAC motors - where have you seen the most activity in conversion to PMAC to date?
A: Although we did not collect information on market adoption rates of PMAC motors, it seems reasonable to expect that the adoption rate would be highest in market sectors where PMAC motors’ advantages over other motor technologies are the most pronounced – such as automotive or maritime applications where large power-to-weight and power-to-size ratios are required; applications with highly variable speed requirements, and applications where synchronous operation offers an advantage.
Q: The motors with issues of harmonics are 200-300HP, 480V...which type would be better for this application?
A: It sounds like the person who asked this question has harmonic issues with a few motors and is wondering whether to use MCASD or VFDs. If that’s the case, I would suggest getting quotes for MCASD and VFDs and comparing costs. Knowing that the energy savings from MCASD is approximately 2/3 that of VFDs and comparing the relative cost of each should help clarify which is better for this application.
Q: If PMAC motor is loaded very lightly, does power factor drop as low as it would for a lightly loaded induction motor?
A: Power factor is usually higher for PMAC motors than induction motors at full load. We didn’t obtain any information about how power factor in PMAC motors varies with partial load; however, manufacturers of PMAC motors should be able to supply this information.
Q: Which is best for low or no harmonics?
A: Depends on the application. However, in general, VFDs have higher savings and are a better option.
Q: PMAC: is this motor controllable thru a BMS?
A: If the motor is not a line-start PMAC motor, then it will require an electronic drive to start and operate. These drives often also provide VFD functionality, including the capability of interfacing with BMS controls.
Q: Do you have any recommended resources to check out to find out more about these technologies? what did you consult when preparing for this webinar?
A: Here are a few resources to check out:
Nicor Gas, Emerging Technology Program, 1026: Destratification Fans, October 2014
Aynsley, R., “Saving heating costs in warehouses”, ASHRAE Journal Vol. 47, No. 12, Dec. 2005.
Also, please visit our technology profiles for more details. Each of these profiles has a “references” section with additional resources listed.
Q: Are there any settings in which PMAC motors are NOT recommended?
A: PMAC motors would not be recommended in applications requiring a very high motor shaft speed (where back EMF becomes significant) or where risks from pinch, shock, or magnetic field hazards become unacceptable. Also, PMAC motors might not be suitable for applications in which their advantages (higher low-speed efficiencies, higher power-to-size ratios, synchronous operation capability) are not important considerations.
Q: ASD: Any ground requirements for magnetic couplings like that for VFDs?
A: EC&M, a technical magazine has a nice summary article of the grounding requirements associated with VFDs that might be worth sharing:
Grounding requirements associated with a PMAC motor need to conform with the NEC and other local codes. In most cases, grounding of the motor frame is required and/or is good design practice to reduce the risk of electric shock if a motor’s insulation system were to fail.
Drew provides consulting services to building owners, architects and engineers to design buildings which achieve a high level of energy performance in tandem with a high degree of occupant health and comfort. His work involves applying principles of energy science to inform real building designs; educating other professionals about energy-efficient technologies and practices; and achieving a holistic relationship between energy performance and other favorable design outcomes.
Drew’s analytical skills are complemented by extensive design, research and field experience to arrive at recommendations that are both innovative and practical.
Drew has a Bachelor of Mechanical Engineering (Energy Systems Concentration) and a Master of Science in Renewable and Clean Energy from the University of Dayton School of Engineering.
Scott Schuetter PE, LEED AP
Senior Energy Engineer
Scott analyzes efficient building designs and researches various energy efficiency technologies. He has extensive experience with both energy and daylight modeling. He served as program manager for the Daylighting Collaborative. Scott is a large-scale batch energy modeling specialist who focuses much attention on modeling campuses, communities, and regions. In addition, he studies climate change impacts on building energy consumption and demand. He is an active member of ASHRAE.
Scott has a bachelor’s degree in physics from Indiana University and a master’s degree in mechanical engineering from the University of Wisconsin-Madison.