For example the frequency of the AC mains supply is, in North America = 60 hertz) and elsewhere is often = 50 hertz.
Maybe what is being referred to is the affect of 'reactance' in an AC circuit? Reactance (as compared to pure DC resistance usually designated 'R') is the affect on current/voltage by the presence of inductors or capacitors in a circuit.
In an inductive circuit the current flowing will 'lag' behind the applied voltage due inductive reactance often designated Xl. In a capacitive circuit the current flowing will 'lead' the applied voltage due to capacitive reactance often designated Xc.
Barring anything else frequency will not 'affect' induction. Current and voltage will be 'affected' (if we must use that affected word) by the frequency of the voltage applied; this is how, for example, low pass and high pass filters work!
Also in this discussion thread suppose the frequency is zero? i.e. DC (Direct Current). Inductive reactance would be nil. Capacitive reactance would be infinite (after initial charging). The affect of 'inductive reactance' on the current flowing would be nil.
Frequency does not effect power, as a purely inductive or capacitive load does not draw any power (not counting any losses due to the tiny resistance of the conductors themselves, which means that you can never really have a purely inductive or capacitive load!).
Since the impedance will be affected by frequency, the total current draw will be changed as a result of a frequency change.
The cosine of the angle between current and voltage is known as the "power factor". In a purely resistive load, it is 1. In a purely inductive or capacitive load, it is zero. Typical loads lie inbetween, but it is best to keep it as close to 1 as possible.
Industrial customers of electric utilities must maintain as high a power factor as possible. They usually have banks of capacitors that can be automatically switched on and off as needed as they will have heavy inductive loads from motors. If they maintain too low a power factor, they will be charged for kVA-hours instead of kW-hours.
For instance, if you maintained a 0.5 power factor, then a 100 A load at 120 V would be 100 x 120 x 0.5 = 6000 watts. An hour of this would be 6 kWh, but it is 12 kVAh.
Why be charged for more energy than you actually used? Simply because you are a burden on the system. Even though your load was only 6000 watts, you drew double the current than was really necessary for that amount of power. Therefore, the infrastructure needed to deliver that power had to have twice the capacity than was really necessary.
Low power factor loads tend to be inductive, so a bank of capacitors can cancel it out. Inductors cause current to lag behind the voltage, while capacitors cause current to lead voltage. The two cancel each other out. In the example above, since capacitors store and release current, they supply the "extra" current needed for the inductive load, so the only current draw on the supply is for the current actually needed to provide power. If perfectly matched, the 6000 watt load would draw 50 amps from the supply while the other 50 amps would be current between the inductive load and the capacitors.
As an interesting side note: your home probably has a leading power factor most of the time. The wiring in your home actually acts as a capacitor. When I was a student, I worked on weekends as a watchman at a factory. There was a power factor meter where the bank of capacitors was. When the factory was shut down and the only load was lighting, the power factor was usually 0.7-0.8 leading. As machines were started up and the inductance of the load increased, the PF would rise to 1 then start dropping on the lagging side. I believe a bank of capacitors would be switched in when it dropped to 0.7. In addition to the kWh meter, there was a kVAh meter.
"Frequency does not effect power, as a purely inductive or capacitive load does not draw any power (not counting any losses due to the tiny resistance of the conductors themselves, which means that you can never
really have a purely inductive or capacitive load!). "
Frequency does not affect power ONLY in a load that is purely inductive or capacitive, because there is no power dissipation there. However, in the general case, frequency does affect power consumption. Consider a load consisting of a 5 ohm resistor and an inductor in series driven by a 10volt source of variable frequency. At 0 freq, ie DC, the series load looks just like a resistor and the power dissipated is
20watts. At inifinite frequency, zero current flows through the resistor, and the power dissipated is 0 watts.
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