Power Factor Correction and Harmonic Resonance: A Risky Combination
Capacitors are intended to solve problems, but if not properly specified, they can also create new ones.
Industrial and commercial customers are always examining their monthly electrical usage for cost-saving opportunities. Installing power factor correction capacitors can help reduce penalties imposed by utilities, often leading to a quick return on investment. In locations like hospitals and paper mills, the payback...
Variable Frequency Drive Cable Length Resonance Frequency
This is a continuation of the article Effect of Cable length on Variable Frequency Drive.
Cable Resonance
When dealing with Variable Frequency Drives (VFDs), the cable length between the VFD and the motor can introduce certain electrical challenges, one of which is cable resonance. Resonance occurs when the frequency of the drive's output waveform interacts with the natural frequency of...
Effect of Cable Length on Variable Frequency Drive
Every cable has, apart from its resistance, certain inductance and capacitance. The inductance and capacitance is roughly equally distributed along the cable length. Inductance L and capacitance C in a circuit create a resonance.
[caption id="attachment_18636" align="aligncenter" width="600"]
Equivalent Circuit of Long Cable[/caption]
The formula for cable resonance is
[pmath size=20]omega_res=1/{l*sqrt{LC}}[/pmath]
Where:
ω =...
Equivalent Circuit of Long Cable[/caption]
The formula for cable resonance is
[pmath size=20]omega_res=1/{l*sqrt{LC}}[/pmath]
Where:
ω =... 
PEC, NEC and IEC Comparison of Cable sizes
Administrative Order of 1987
The Philippine Electrical Code (PEC) is based on the National Electrical Code (NFPA 70) with a major update on changing the Imperial Units to Metric Units in compliance to the Administrative Code of 1987, the metric system of weights and measures shall be used in the Philippines for all products, articles, goods, commodities, materials, merchandise,...
Key Differences in Power Transformer Selection According to International Standards
Power transformer sizing standards according to IEEE (Institute of Electrical and Electronics Engineers) and IEC (International Electrotechnical Commission) differ in certain key aspects. Here's a breakdown of the major differences between the two:
