JOHN @ URI

Don,

Could you please do some testing on the following?
Use 2 100w choke ballast to run a 79" lamp.
VS.
Use a 180w choke ballast to run a 79" lamp.

The 79" lamp is designed to be run at 180W.

I would like to know which is more efficiant and which would produce more output.

Is this something that you could do?
Please advise.

Don Smith

John:

Yes, we can do this test for you but I'll have to get a 180 watt ballast and some 79" sunlamps first (can you help?). Please call me (1-520-975-0180) to discuss this when you get a chance.

I'll post the results when the test are completed.

Don[ This Message was edited by: Don Smith on 2002-05-23 06:29 ]

JOHN @ URI

I'll try to call this afternoon.
Your on hollywood time...

JOHN @ URI

Don, I did the testing here on our test rack.
Here are my results:
I used a 79" Cosmolux VHR 180w lamp.
235 volts, new lamp w/ 5 min warm up.

With(1)160w Choke ballast: 5.0 meter = 27.4,
6.0 meter = 1.39, 7.0 meter 12.7
(did this for comparison 180w lamp w/160w ballast, lamp is under powered-14 min session)

With(2)100w Choke ballast: 5.0 meter = 32,
6.0 meter = 1.64, 7.0 meter = 16.9

With(1)180w choke ballast: 5.0 meter = 32.5,
6.0 meter = 1.61, 7.0 meter = 16.9

Both would be an 11 min session, Just like Sontegra got on their beds using the 180w choke ballast with the 79" VHR.

I then switched the lamps & got similar readings.

So much for the claims of true 200w systems using this 2 ballast combo.

Don, What do you think?

I'd like to get a suncapsule 200w ballast if bossible to test that with the 79" lamps.
[ This Message was edited by: JOHN @ URI on 2002-05-29 10:54 ]

solarmeter

John,

How many lamps in test rack? What distance from lamps were readings taken at?

FYI, your model 7.0 is set at 210 J/m^2 per MED. So applying the 1.34 factor (for FDA 156 J/m^2) the MED/hr goes from 16.9 to 22.6.

And Te = 240/22.6 = 10.6 min (round off to 11 min) just like you said. Good test.

Steve

JOHN @ URI

I held the meters on a stick about 3" from lamp, This was done consistantly.

Single lamp testing. Using Cosmopower Ballast.


I'm sure that I didn't do it the most scientific way But I could send them to Don.
I'm sure he'll find the same results.[ This Message was edited by: JOHN @ URI on 2002-05-29 11:22 ]

JOHN @ URI

Steve,
The 7.0 meter is awesome. What a great tool.

solarmeter

John,

I'm supprised you got such a high MED/hr from a single lamp at 3". Is it reflector or non? Did you already apply the 1.34 convert factor to get 16.9?

Or did you bump all values by a certain percent to represent an 'array' in a bed? Or maybe 180-200 watt lamps are just stronger than I imagined...

Steve

JOHN @ URI

Steve,
The lamp is a reflector lamp.

The numbers you see are the numbers that the meters said.

I did the formula to switch that 16.9 to the estimated 11 min to 4 meds.

Don Smith

Steve:

One of the "anomalies" is that the distance isn't as critical for your meters as it is for the spectroradiometers. I'm not sure why, but we've noticed this before.

However, we still place the "detector" of all of the devices at 10 cm from the bottom wall of the sunlamp in a test stand as per the 2/7/02 meeting.

John:

It was good talking to you this morning!

Your data doesn't surprise us. As mentioned, we powered a 600w HP sunlamp with a 500w and 2 100w ballasts and then with the 500w and the 100w and got the same readings (when the voltage was the same).

If, however, you vary the incoming voltage, you will get a significant difference in te (time to 4.0 MED) time readings. As a rule of thumb, +(-) 5 volts will change the te time by about one minute.

I started out enamored by the UVI meter but now I use the MED/hour meter almost exclusively. Moreover, I get a real "charge" out of those who post A & B meter readings thinking that they tell you much about the performance of the sunbed.

Don