Poworer fact
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kwired
Electron manager
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Efficiency may not be same eithe, only thing that is same is they both should be designed to drive the same 150 watt lamp but how they get there can be different.
kwired
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Lamp condition could make some difference as well. HPS draw more as their life is used up. When they start to cycle at end of life it is because they are drawing more current then the ballast can deliver and the arc is extinguished. Once pressure in arc tube drops enough to restrike it starts process all over. Cycling gets shorter and shorter as the lamp draws heavier current as it continues aging.
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That would be true if the efficiencies are equal.
Bugman1400
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I don't understand why a higher power factor would be less current draw. Isn't just the angle between voltage and current different?
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If the resistive part of the current (which lights the lamp) stays the same, then the magnitude (length) of the actual current vector must be greater. (The actual current will be the hypotenuse of a right triangle, whose length must always be greater than the length of either side.)
This is most obvious when you look at a phase angle greater then 45 degrees.
kwired
Electron manager
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- NE Nebraska
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- EC
Voltage stays the same.
If you are familiar with power factor triangle the base represents true power(watts), the hypotenuse represents VA (which contains the amps that you will measure with a ammeter and what does create heating effects in the conductor) and includes any reactive current -which is what causes us to have a power factor in the first place.
Divide each number by voltage to get current relative to the figure represented. The hypotenuse is always the long side of the triangle and always is the side that also contains any reactive current.
If there is no reactive current the PF is 100%, the watts and VA will both be the same so the PF triangle with 100% PF present is not a triangle but rather just a straight line.
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