David Chesley, PE, LEED AP, RCDD, Interface Engineering, Portland, Ore.

Articles

HVAC/R and Mechanical April 28, 2015

Leveraging the BAS

By using the building automation system (BAS) to its fullest extent, a school district was able to control its HVAC, electrical, and lighting systems.

By David Chesley, PE, LEED AP, RCDD, Interface Engineering, Portland, Ore.
Motors and Drives September 17, 2012

Avoiding harmonics in HVAC and electrical systems

Power electronics can increase energy savings, and at the same time can distort the quality of electrical power. Here are some tips to mitigate harmonics.

By David Chesley, PE, LEED AP, RCDD, Interface Engineering, Portland, Ore.
Electrical and Power September 17, 2012

K-rated or harmonic mitigating transformers

Just as current harmonics can cause additional heating and losses in the magnetic core of a motor, they can produce much the same effect in the iron core of a transformer. However, greater losses from harmonics can occur in the windings of the transformer.

By David Chesley, PE, LEED AP, RCDD, Interface Engineering, Portland, Ore.
Electrical and Power December 14, 2011

Understanding standby power system grounding

Knowing how to apply proper grounding and bonding to electrical systems and transfer switches for common standby power system configurations can minimize power outages, equipment damage, and injuries.

By David Chesley, PE, LEED AP, RCDD, Interface Engineering, Portland, Ore.