Magnetic/Electric(Digital) Ballast questions answered.

[420 HELI]

http://maximumyield.com/article_sh_db.php?...p;issueVar=June

 

The Digital Sun: Better Light for Better Results

 

by Erik Biksa

2009-06-01

 

There has been quite a ripple in the world of hydroponics since the introduction of digital lighting systems, sometimes referred to as electronic lighting systems, since their appearance within the last decade or so.

 

As with many emerging new technologies, some of the first generation units showed us lots of promise; and in some instances they delivered on those promises, in others reliability was an issue with a few wrinkles that needed to be ironed out.

 

In the past, unit wattages of 400 watts or less had proved to be more reliable, as manufacturers and engineers had not yet conquered the higher wattage outputs, especially given the inconsistency of input voltages and the quality of electricity available in different parts of the globe. Some of the earlier un-shielded models also created RF (radio frequency) interference, causing problems with communication signals such as radio, wireless internet and cable.

 

At present day, growers have some exciting options when it comes to choosing lighting systems for their indoor and greenhouse crops. Next generation digital ballasts outperform their magnetic/core and coil predecessors, while offering options and functions that are simply not available using the older core and coil ballast technologies. The higher wattages are typically very reliable now, and the holy grail of 1000 watt digital HID reliability is now here.

 

Gone are the days of loud buzzing and humming, a situation with core and coil ballasts that becomes compounded with multiple ballast installations, especially overtime with ballast wear. Traditional ballasts, while reliable, produce a lot of heat that can be problematic. The heat produced is indicative of a less efficient process in converting the power coming in to power that is suitable for maintaining an arc in MH (metal halide) and HPS (high pressure sodium) lighting. This means that you are getting less light for every watt consumed, with more heat and bigger power bills versus high quality next generation digital/electronic HID lighting systems.

 

So where do these differences in efficiency originate from when comparing digital ballasts versus core and coil ballasts? Primarily it’s in the fact that the digital units are using circuits and micro-processors to regulate wattages and electrical qualities, making them “smarter” over mechanical technologies such as core and coil ballasts.

 

Core and coil ballasts use metal wire windings (coil) over a series of metal plates (core) to regulate or ballast the flow of electrical current to the lamp. HID lamps require ballasts because they have stricter requirements about the amount of voltage it takes to strike and maintain an arc in the lamp versus incandescent home lights. The arcing of the lamp produces light because the ballast sends the right amount of electricity through the arc tube, which excites and ignites the blend of particles. Once ignited, the particles become a gas that creates light for crops. If too little electricity is sent, the bulb will not stay lit; if too much is sent it will burn the bulb out or damage it beyond usability.

 

Most of the core and coil ballasts used for growing indoors are Controlled Auto Wattage (CAW) transformers. They allow for a +/- 15 per cent difference in the amount of electricity coming in to keep a specified lamp lit while keeping it supplied with the correct amount of power. If there is too much variance in the output of the ballasts due to fluctuations in the electricity available, the lamp will not be able to stay lit or will “pulse.”

 

As a matter of fact, one of the reasons electronic ballasts produce stronger light that is more useful to plants is that they do not pulse as much as lighting sources originating from magnetic (core and coil) sources. Part of the reason is that core and coil ballasts operate at lower frequencies, very much resembling line voltage frequencies of 50 to 60 hertz. Hertz (Hz) is the measure of how quickly a magnetic field is expanding and collapsing per second. Remember that the nature of the electricity we use is based on the principle of an expanding and collapsing magnetic field, with the occurrence at a rate of many times per second, i.e. in our 50 to 60 hertz line voltage frequencies.

 

This relatively lower frequency translates into the quality of light being emitted by the lamp. To the plant, the light is actually blinking 50 to 60 times per second, creating a strobe effect that is not often visible to the human eye; however, plants seem to sense it.

 

Digital and electronic ballasts deliver their electrical lighting loads at much higher frequencies, for example greater than 10,000 hertz. This means a more constant “on” of the lamp, with reduced pulsing or strobing of the light. Plant growth responds better to the lessened incidence of strobing created by digital lighting systems. Not only do plants benefit, but so does the grower as lamp life is increased, and the overall intensity of the lamp output is also increased. Nikola Tesla, regarded by many as one of the most brilliant electrical scientists/engineers to have walked the earth, seemed to have gravitated towards higher frequency electrical currents greater than the 10,000 hertz range as with digital ballasts versus the 50 to 60 hertz range used with core and coil/magnetic ballasts.

 

Because digital ballasts are using smart technologies to help generate optimal lighting frequencies rather than mechanical ones as with core and coil, they offer some savings in the amount of electricity consumed. However, they do an even better job of converting the amount of electricity consumed into optimal frequencies for maintaining an arc in the lamps used for lighting. For example, no device is 100 per cent efficient. Power Factor (PF) is a relative measurement of the efficiency of electrical devices, basically stating how much power is being lost and unavailable for “work” compared to the amount of power being consumed.

 

Most core and coil ballasts have a PF rating of about 0.85, meaning that 85 per cent of the electricity being consumed is being translated into use for “work,” in this instance maintaining the arc in the lamp. The 15 per cent that is lost emanates as heat, which is a form of waste, helping to explain why core and coil ballasts tend to run so hot.

 

High quality next generation digital ballasts have PF ratings of 99 per cent and higher. This means that the majority of electricity being consumed is being translated into usable electricity for lamps, due to the smart processing of the electricity by modern day circuits. Most growers who have adopted the digital age of lighting and made the switch find they are saving about five to 10 per cent on average in electrical usage, and in some instances much higher. Although growers get excited about less electrical draw, because it allows them to safely run more ballasts on the same circuit and because of the reduction in power costs, the real joy is in the increase in lumen output from their lamps.

 

Some brands and wattages of lamps are better suited to accepting the greater than 10,000 hertz frequencies delivered by digital lighting. In most cases lamp output is actually increased by around 10 per cent, which is quite significant. The amount of light energy delivered to crops has a strong correlation to the potential yield of indoor crops and the overall quality of the harvest; provided other environmental conditions are managed. Not only is the sheer intensity improved, but as stated previously, so is the quality of light due to a reduction in the incidence of strobing. Lamp manufacturers with their eyes on the future have begun to develop lamps that are specifically manufactured for use on the higher frequency operating digital ballasts. This offers to increase the output potential of digitally driven lighting systems even further.

 

Besides the improvements of how digital ballasts operate versus core and coil types, there are some capabilities and features you can find in next generation digital lighting systems that you just won’t find in common core and coil systems used for growing crops under artificial lighting.

 

First off, digital lighting systems don’t create a huge spike in your electrical draw on ignition. This spike can be especially problematic when starting up a number of ballasts at the same time. Start-up is when you are most likely to trip a breaker that would normally be okay while the lamps are operating. Digital ballasts do not create this spike, as they gently and quickly drive lamps to full brilliance, typically in less than one minute. This helps to eliminate power spikes, and allows growers to maximize the number of ballasts they can safely run on a given rated electrical circuit. These softer starts help to extend the life of the lamp, as well as helping to preserve the quality of light being emitted by the arc tube. Because digital ballasts are capable of driving your lamps brighter, you may still want to replace your lamps as often as with core and coil types. In a sense, you are replacing them due to how brightly they burned, rather than how inefficiently they were ignited.

 

The distance at which lamps can be ignited, and still achieve their maximum rated lumens, is also improved with high quality digital lighting systems. Lamps, including 600 watt models can be ignited at distances of 65 feet or even greater. Very few, if any, core and coil types have been able to achieve this, especially when using high quality horticultural lamps such as the one featured in this article.

 

The fact that digital ballasts will ignite either MH or HPS lamps is an excellent advantage. While conversion and retro-fit bulbs are available for allowing HPS lamps to be used with MH core and coil ballasts and MH lamps to be used with HPS core and coil ballasts, the bulbs are pricey and tend to sacrifice some lumen output for their cross-over capabilities. With digital ballasts, you can use a wider variety of lamps on the same unit.

 

In fact, certain models of next generation digital ballasts can run more than one type of lamp wattage from the same ballast, giving it a wattage switching capability. For example one of the digital ballasts featured in this article can switch from 400 watt HPS/MH capabilities to 600 watt HPS/MH capabilities.

 

All the grower needs to do is turn the power off, switch the lamps, flick the 400 watt/600 watt selector switch and then run a different wattage lamp. This is perfect, because growers can supply a vegetative photoperiod in a three foot by three foot area with a 400 watt MH lamp. When triggering the plants into flowering or up seven days after initiating the 12/12 photoperiod for short day plants, the 400 watt MH lamp can be replaced with a 600 watt HPS lamp. At the flick of a switch, optimal light levels and spectrums can be supplied for the flowering phase.

 

This is very convenient and produces excellent results. The grower does not need to move the plants, or change lighting systems from vegetative to flowering growth, making growing in deep raised beds even easier! Because the grower is switching lamps periodically, bulb life is extended, providing yet another benefit.

 

As mentioned previously, digital ballasts also run quieter and cooler. Some digital ballasts encase the circuits with a resin, and the heat generated by the unit is passively vented. These types of units run completely silent. Other innovative digital ballasts use fan-cooling to keep the ballasts’ temperatures even cooler. Cooler circuits run more efficiently, creating a greater potential for light output. In some digital ballast units, the ballast cooling fans are thermostatically controlled, and also integrate fail safe sensors and functions. For example if the internal ballast temperature rises to over 162°F, the cooling fans will speed up, and the condition is indicated to the grower with an LED flashing function on the ballast. If temperatures exceed 194°F, the condition is also indicated to the grower with a flashing LED display. Either condition should not occur if there is adequate ventilation for the digital ballasts; the smart technology is actually telling the grower they are doing something wrong. Core and coil ballasts will not do this, and always run much hotter than digital ballasts operated in the same type of environment.

 

There are many other advantages that digital ballasts can offer besides power savings, increased light output, improved quality of light, cooler operation and less noise. For example, most units are extremely lightweight versus traditional core and coil units, as well as being more compact. Potentially, the grower can house more ballasts in the same amount of space with a much easier and less weight to handle installation.

 

While core and coil ballasts are very reliable, in fact you could use one as a boat anchor, haul it up, dry and clean it and fire it up again (don’t try this at home), they cannot perform many of the smart functions and operations that digital and electronic ballast systems do for horticultural lighting. Just as there is a new breed of grower, there is also a new breed of lighting technologies that help to improve the growing process and give better results. There is an optimal lighting system for each individual application, so take some time and do the research to find the one that is right for you.

 

so now you know

[nitram]

HI HELI,

 

Another great find ........................ but your source is very good and reliable ..............I used to subscribe to Maximin yield magazine as the were 'collectors items' for the avid grower.

 

I have their 'online magazine' subscription which is reasonable @ $65.00. Always good quality photos and articles.

Subscription forms you can get on the web site. Bit if your the surfing type use their website.

 

Great find once more HELI ................. the organic one the other.

 

Now on with a comment on the Electrical ballasts (E-Ballast).

 

I have been doing my own bit of research as I am 2 - 3 weeks of buying one.

 

all what is in this article sums up very well what I have learned.

 

I don't see much critical input on what has been reported about the various e-ballasts varieties and defo no mention of a brand name. That's how balanced journalism works.

 

So, I will kick off this with my comments in the hope I get stimulating debate and more so 'real experienced' & 'very reliable' information from those amongst us with actual use they could share.

 

Firstly my 'enlightenment', or 'gestalt'. I was always aware of the existence of 'varieties' of e-ballasts. The principal design difference I was fixated on was with cooling. Their are 2 design differences, either cooling being active (using centrifugal fan I believe) or passive (no fan just resin coating & vents. It has only just clicked to me from reading this over that I had possibly mistaken the latest & greatest, or latest generation, ones as being those that are NOT air cooled by a fan (Active cooling).

 

I won't go on about generational confusion but make my point.

 

My granddaddy told me "If it moves it can break. If it's got bearings then it can wear out." He was prettuy much a pesimistic frustrated old, yet wise & experienced mechanic.

 

Having just recently looked at fans in great detail 'centrifugals fans' are 'bearing base architecture i think' - that why I didn't buy a centrifugal fan due to noise (stealth).

 

Regardless my point is that I am wondering if I would be correct to think that some e-ballast's that are air cooled do so using centrifugally fan based architecture? Now i am looking to cheat and not search out forms after form to find out as I know I can get my reliable 'experience' information from people who visit this page and use e-ballasts. Share !

 

Nitty.

[jimbojones5678]

Nice read, thanks

 

Jimbo