New 100 Watt Lamps - Meter at 18. Is this normal?

[Brian Oshman]

TA beds with electronic ballasts (and the mag ballasts too) do not need boosters so your voltage for those beds are correct.

Lamps run best at a temp. of 108°F. That is the internal temp. of the lamp and you won't be able to measure that with an infrared thermometer. The acrylic surface should read 78-80°F after the bed is warmed up for a couple of minutes while running.

18-20 mw/cm² A+B on the 5.0 meter are normal for 100 watt base beds using non-reflector lamps.

The higher numbers you see commonly posted are for VHR and HP beds.

[solarmeter®]

Even if 18-20 sounds "low" to some folks.... it is still 3-4 times more than summer sun which is 4.7 - 5.7 depending on your latitude. Sun is also around 4 -5 MED/hr on a 7.0 meter.... or about an hour to 4 MEDs fyi.

[mstnt]

Thank you for the info. I now have one temperature that the lamps should operate at confirmed from two sources. Do the manufacturer's of the lamps spec that temp?

Also, appreciate the feedback that the readings I'm getting are normal.

[Jessie]

Anything over 20 for a base bed is never a good thing unless you want to keep them there.

[mstnt]

Well, that's one way to look at it.

[Drew]

I know on the Leg Tanner lamps...they started going down in output at 107 degrees and below 100 degrees.

Anyway...my 24 lamp puretans with mid day suns will do 18 mw's new. My Sundash Genesis with Beach Sun Reflectors will do 38mw's new. I run those at 12 mins since that is 4 meds at 12.

[mstnt]

Forgot to mention/update. A couple of weeks ago TA sent out fan delay relays which were set to come on about a minute and a half after the bed came on to give the lamps a chance to heat up. We changed them out but it didn't seem to make much of a difference. I tanned in one of the beds right after changing the relay. I stayed in the full 20 minutes. The bed never got very warm and I didn't see any color myself (I had only tanned twice the last six weeks prior). The meter readings stayed the same and now our customers are freaking out because the fans don't come on immediately. TA is sending out a technician today to check out our equipment. Anybody got any suggestions on what they should be checking for?

[mstnt]

PS. I just purchased a 6.0 and 7.0 from Steve @ Solarmeter.

[solarmeter®]

If he brings out his spectrometer, don't let him leave until he sums up the nm by nm irradiance as three bandwidths:

1. Total UV from 280-400nm (like a model 5.0 sees)
2. UVB from 280-320nm (like a model 6.0 sees)
3. Erythemally weighted UV from 280-400nm (like a model 7.0 sees and converts to MED/hr).

Then when you get your 6.0 and 7.0 meters you can compare.

For 3. above, the spectrometer scan might be from 250-400nm. If so that's OK because there is virtually no UVC from 250-280nm. The Ery weighted irradiance might be in W/m² or some similar units. That's OK too because I can convert that to MED/hr.

If the lamps are 5% UVB.... and the total UV is say 18.0 mW/cm²... then the UVB should be about 0.05 x 18.0 = 0.90 mW/cm². A "ratio" of UVB/UVA would be slightly higher "percent" but close.

The amount and percent of UVB is not as important as the MED/hr. Knowing that will help determine if the Te time to 4 MEDs is OK with the lamps/beds you have. Shortcut is Te = 240 / MED per hour.

And... needless to say... the hand held meter readings and the spectrometer readings should be taken at the same location. Usually center of bed pointing up near belly button position with canopy closed.

Readings from the bench are almost always less. That's OK too.

[Jones]

Steve you need to invent a remote so you can put the device in be, position it, shut the canopy, meter bed and lock the number in so when you open the canopy you have meter reading...it's very hard to close canopy and read the meter in smaller rooms!

[mstnt]

Steve. Cool. Thanks for the info. That sounds like I'll be comparing apples to apples at least.

[solarmeter®]

Shari.... yeah I've had a number of requests for that. Maybe someday. I'm trying to keep the meters cheap so most folks (except maybe Elite Mike lol) can afford them. No price increases for many years.

Some people in other industries (like screen printing UV machines) actually open up the meters, remove the sensor from it's plug-in connector, fashion a wire/cable connected to sensor pins, and plug the other end back into meter connector.

But the circuit board doesn't have a "hold" feature... so the remote reading just gets written down and saved.

[Jones]

I always wanted them in all equipment so tha we could read at anytime via our software. I like that amp and volt meter in beds for a constant look too!

[solarmeter®]

Trouble is... the sensor would have to be right where the person lies. Or - if it was way up close to the canopy it would just be measuring one lamp. I think some company tried that several years ago.

The other reason that wouldn't be very accurate is that a sensor constantly exposed to UV will solarize and lose sensitivity over time. Also dust and tanning lotion on a sensor will reduce the sensitivity.

Not saying it's impossible... just that for correct numbers readings should be taken at belly button position. And any kind of permanent sensor would obviously be in the way.

[solarmeter®]

For mstnt (what does mstnt mean btw?)... so what happened?

Or did he just confuse you?

[solarmeter®]

Well..... any results? Confusing or otherwise?

[kookyguy]

Hey mstnt, How is the HP doing?
Did you guys bring in a standup yet?

[dcjjp1]

I just finally used this 5.0 on my new Sundash lamps Beach Suns's with and it measured 28 on them with about 20 hours on the lamps. Is this normal, I thought it was kinda high from what I have read.

My Sunstorms are running about 56 (200 hours on lamps) I need to do the putting 2 new ones next to one another to see the difference.
and Sungate 70 at 44 hours on lamps????

[John]

mstnt,

Lamp wall temp should remain at or about 105º throughout the session.

If someone came in & changed your magnetic ballast for new electronic ballast & they didn't change/adjust cooling, sounds very fishy. The electronic ballast run much cooler than old Magnetic style ballast. They are more energy efficient and are much easier on the lamps.

My question would be: was the bed originally under cooled & when they put new electronic ballast in, is it where it is suppose to be now?

Or: Was the bed cooled right to begin with & now is it over cooled?

[John]

Jeff,

Every bed & enviroment is different. Those are some good numbers in any bed for a 6.5 100W standard.