What does cos phi mean?

Power factor: With alternating current, the recorded (or apparent) power (kVA) of an inductive load is greater than the active power (kW) used in the calculation.Cos phi = active power/apparent effect.Examples:A. Resistive loads such as filament lamps and heating elements: cos phi = 1B. Inductive loads:Electric hand-operated tools: cos phi ~ 0,97Electric motor: cos phi = 0.7 — 0.8Fluorescent lamps, welding transformers: cos phi ~ 0,5

2020-10-19T10:13:27+01:0019. October 2020||

What is meant by LWA, and what is the ratio of LWA & dB (A)?

The current European standard claims that all manufacturers = 2 kW must not exceed LWA95. LWA95 is equivalent to 70 dB (A) at a distance of 7 metres. We can say that dB (A) of 7 meters = LWA — 25. dB (A) of 4 m = LWA — 20 dB (A) of 0 m = LWA — 0 = LWA The sound level is dependent on the type of engine (petrol or diesel), the number of revolutions, and [...]

2020-10-19T10:10:49+01:0019. October 2020||
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