Q.1 Why is my Lumatek E-ballast 20% brighter than my old magnetic ballast, but my friends Lumatek is only 15% brighter than his old magnetic?
A. This is because of the powerful effect voltage has on magnetic ballasts. A 240v magnetic ballast is designed to work with 240v. At 240v the lamp power (power provided to the lamp) for a 600w ballast is 600w. However, for example, in reality, the UK voltage range is anywhere from 215v to 258v in our experience. Because "Power = Current X Voltage" in a device like a magnetic ballast (a linear device), when voltage changes, so does the power of the ballast and therefore the light it produces. When voltage drops a mere 20v from 240v to 220v a magnetic ballast will typically dim by 20%, leaving the Lumatek 20% brighter. At 210v the Lumatek is 30% brighter. The Lumatek is a voltage regulator and will respond with the same light output over its entire voltage range. Always the same light output, every minute of the day. So the simple answer is: it depends where you are and what your voltage is.
Q.2. My magnetic ballast is brighter at certain times of the day, why is that?
A. This is because voltage varies throughout the day. It is not uncommon for voltage in a household to vary by 10% over a day. This is because voltage drops as more "load" (electricity consuming devices) is added to the household circuit, and the larger local electricity supply. As large industrial users turn on, local voltage drops, thereby dimming local lights. This effect occurs even as more HID lights are added to a circuit in a building. We have all noticed house lights suddenly dropping at certain times of the day.
Q.3. I used to get 6 x 600w magnetic ballasts on my circuit before tripping the circuit breaker. I can now get 7 Lumatek 600w E-Ballasts on that same circuit. How can that be possible?
A. This is because of the high "power factor" of a Lumatek E-Ballast. Without getting too technical, when a device has a low power factor, the electricity company has to supply additional power to the device to compensate. Because of the way electricity companies bill you, this extra power is not measured by a power meter but is "felt" by the circuit breaker. Therefore an additional almost 10% of power is supplied by the company causing it to "trip". Therefore where six magnetic ballasts would work before, now seven Lumateks will.
Q.4. When I checked my magnetic ballast with a power meter it told me the ballast was drawing far more than 800w, for a 600w ballast that's not possible surely?
A. I am afraid it is, using "Power = Current X voltage" we see that at voltages above 255v (quite common in parts of the UK) a 600w Ballast will in fact be drawing more than an 800w ballast! If you have ten of those you can imagine the effect on power consumption.
Q.5 If my magnetic ballast changes power, does that affect the PAR light my lamp produces?
A. Obviously the amount of PAR light available has an effect on the growth of plants. PAR is the part (frequency) of light that plants use to grow. Lamp manufacturers design their lamps to produce a certain amount of PAR over the power range of the lamp. For a 600w lamp a range of 585w to 660w of lamp power produces normal PAR as designed. As the lamp power goes above or below that range then the frequency of light it produces changes: more to the blue spectrum when overpowering and more to the red when underpowering. This has an effect on the growth rate and development of plants. If you stay within the range (585w to 660w ) there is not much difference, but obviously overpowering your light does cost more energy. Though you strive to have the optimal light every time there are circimstances when you delibetrately may want to dim your light, such as too high temperatures. The light colour changes more to red, but that effect is less dramatic for the plants than the high temperature is. For those purposes we developed dual power (600/400 W and 400/250 W) dimmable ballasts.