Light Flicker In An Office Complex

The second floor of an end unit of an office-condo complex in the Washington DC area. The office space consisted of a reception and meeting area, two private offices, a kitchen area, and a bathroom. The entire area was powered from a single three-phase 208/120V wye feed from a transformer bank located right below andContinue reading “Light Flicker In An Office Complex”

Voltage Transients Causing Diode Failures

A plastic extrusion manufacturer in the mid-West had a 480V delta feeding a plastic extrusion machine. The ASD-driven synchronous motor in the extruder had a half-wave bridge rectifier circuit to provide excitation voltage to the pole coils. Diodes on the half-wave bridge exciter circuit were blowing out, and the filters to the SCRs were beingContinue reading “Voltage Transients Causing Diode Failures”

Harmonics Generated from the Source

The subject company manufactures meat products such as sausage, salami, and bologna. Most of their load consists of HVAC and refrigeration as they have about 6000 sq. ft. of cold room storage. They also have machinery such as grinders, slicers, and presses. The facility is served by a 120/240V through a utility-owned 500 kVA High-LegContinue reading “Harmonics Generated from the Source”

IEC 61000-4-30 Class A Edition 3

The IEC 61000-4-30 Class A standard defines the measurement methods, time aggregation, accuracy, and evaluation, for each power quality parameter to obtain reliable, repeatable and comparable results between various brands and models of PQ instruments and systems IEC 61000-3-30 Class A Edition 2 IEC 6100-4-30 Class A Edition 2 standardizes the measurements of: • PowerContinue reading “IEC 61000-4-30 Class A Edition 3”