The split universal mounting kit version, Split uKIT, of the AEGIS® SGR bearing protection ring protects the bearings of variable-frequency drive motors from electrical damage, and allows quick and easy retrofitting of the ring on virtually any ac motor shaft without decoupling attached equipment.

Driven by variable-frequency drives, the Gen2.0 PremiumPlus+™ brushless permanent magnet motors have motor-only rated point efficiencies of 93 percent and 92 percent for 3- and 5-hp versions respectively. They are packaged in standard NEMA frame sizes and mounting dimensions for easy substitution.

The Air-Conditioning, Heating, and Refrigeration Institute (AHRI) recently published an industry-first standard for variable frequency drives (VFDs).

The Air-Conditioning, Heating, and Refrigeration Institute (AHRI) has announced the publication of an industry-first standard for variable frequency drives (VFDs). As with all AHRI Standards, 1210 (I-P)-2011 & 1211 (SI)-2011, Performance Rating of Variable Frequency Drives, are available free of charge on AHRI’s website at www.ahrinet.org.

This article compares three schemes of fan control used on large air conditioning and refrigeration condensers. The first scheme is step control; the second is a hybrid with a VFD on only one bank of fans, while the rest remain step controlled. The final, and most efficient, scheme is VFD control of all fans, at all times.

GE has announced the successful completion of GE Energy’s $3.2 billion acquisition of Converteam, a leading provider of power conversion and automation systems and high-efficiency power electronics, motors, and generators.

Shaft currents induced by VFDs can wreak havoc with bearings, so a reliable method of shaft grounding is essential.

As part of a renovation plan, Florida State College at Jacksonville researched a number of upgrade scenarios for its chiller plant. Initial recommendations for a conventional chiller failed to meet budget and energy-savings requirements. During the re-evaluation process, the college team visited Flagler College to see a chiller actually using the compressors.

A variable frequency drive (VFD) fails to vary the discharge-air fan speed. A motor overheats and fails prematurely. While each troubleshooting problem in an HVAC system presents its own unique set of circumstances, HVAC professionals may recognize such problems as possible power quality issues.