I posted in another thread that I will begin building my UV lightbox tonight using the free plans linked to from that thread.

I recieved a PM for a fellow APUG member that was suprised at the low cost for the ballast's that I purchased.

The plans call for (6) 120V-20Watt pre heat trigger start ballast, Advanced #RL-2SPS20-RP.

Home Depot did not have these exact ones but their cross referance chart said that a direct replacement would be the GE 08819, so that's what I purchased.

After my PM exchange last night I'm beginning to wonder if these will be OK as I found out that electronic ballasts are better and the ones I purchased that are magnetic. I’m good at wood working but know nothing about wiring up something like this.

Any suggestions or comments would be appriciated. I'd like to have this unit complete by tomorrow evening.

As always thanks in advance.

Jim

Better brains may know more than me on this, but I think magnetic ballasts are slower to start than electronic ones so the first few seconds exposure will be unpredictable. I don't know whether that really matters when the total exposure time is likely to be in the minutes. As you've bought them why not give them a try - you can always replace them if you don't like them. And assuming you're wearing some serious UV eye protection you could also take a peek at the tubes while they're starting to see how quickly and evenly they start...

Thanks for the response Ian. I thought that's what the difference was but not positive.

Jim

Jim, I bought Home Depot shop lights, mounted all the ballasts above the plywood that houses the lights underneath and wired them to each other (grounded each ballast to mounting screws). I'm sure they are magnetic and come on instantly.

Thanks for the info Matt.

I'm almost done putting everything together. All I have left to do is mount the bulb holders and wire those up. Should have it finished tomorrow.


~Jim

Jim, I bought Home Depot shop lights, mounted all the ballasts above the plywood that houses the lights underneath and wired them to each other (grounded each ballast to mounting screws). I'm sure they are magnetic and come on instantly.

MORE THAN YOU REALLY WANT TO KNOW ABOUT FLUORESCENT LIGHTING

The label on the ballast should give the information you need. Besides the voltage and amperage info it should say what lamps can be used and how many lamps per ballast. It also generally has a diagram showing how to connect the wiring.

Lamps are will be marked something such as F40/T12/BL and maybe a number referencing its length. F=fluorescent 40=40 watts T=the connector configuration - in this case bi-pin -- 2 pins on each end 12=the tube diameter in eights of an inch - 12=1-1/4 inches BL or some other designator is the color output. BL is UV BLB is black light UV.

Lamp output does increase as the lamp warms up. If you turn it on at least 5 minutes before you intend to use it, the light output should be stable.

Besides weight and cost, the main difference between the magnetic and electronic ballasts is energy consumption. Electronic ballasts use less power to produce a given light output. They do this by having an output that cycles at thousands of times per second instead of (in the US) 60 times per second. Fluorescent lights go out twice per cycle. At the higher frequency the lamp spends less time "off".

Anyone who has read this far should really see a doctor about that case of insomnia.


Dan

You're right, more info then the average person would want to know but good information.

Thanks for taking the time to explain it.

Jim

MORE THAN YOU REALLY WANT TO KNOW ABOUT FLUORESCENT LIGHTING

The label on the ballast should give the information you need. Besides the voltage and amperage info it should say what lamps can be used and how many lamps per ballast. It also generally has a diagram showing how to connect the wiring.

Lamps are will be marked something such as F40/T12/BL and maybe a number referencing its length. F=fluorescent 40=40 watts T=the connector configuration - in this case bi-pin -- 2 pins on each end 12=the tube diameter in eights of an inch - 12=1-1/4 inches BL or some other designator is the color output. BL is UV BLB is black light UV.

Lamp output does increase as the lamp warms up. If you turn it on at least 5 minutes before you intend to use it, the light output should be stable.

Besides weight and cost, the main difference between the magnetic and electronic ballasts is energy consumption. Electronic ballasts use less power to produce a given light output. They do this by having an output that cycles at thousands of times per second instead of (in the US) 60 times per second. Fluorescent lights go out twice per cycle. At the higher frequency the lamp spends less time "off".

Anyone who has read this far should really see a doctor about that case of insomnia.


Dan