26W lamp ballast(?) troubles - Page 1
Forum section: electronics / repair

author: ICSK
author_rank: Newbie
timestamp: February 12, 2015, 09:14:35 pm
content: Hello, I'm having trouble with my 26W lamp. Both bulbs will work fine at home but when I take it out in the field that's where the problems start. It'll light them both the first cycle but subsequent on/off cycles result in only one bulb lighting and the other flickering. I'm told that means that there isn't enough filament heat?Possible solution 1?Now, before I explain anymore I know the easy answer. My current setup uses a modified sine wave inverter and battery. I'm sure if I switched to pure sine wave it'd work fine. There are two problems though. Cost and size. The only one that I've found that takes up a small footprint is the Samlex 120W, which has mixed reviews on Amazon and is a bit expensive at $100. If anyone can recommend one that takes up a similar footprint or vouch for the reliability of the Samlex it'd be much appreciated.Possible solution 2?Here's a photo of the circuit. I marked the portion that I believe lights up the bulbs. What I want to know is if I can just increase the capacitance in C4/5 so that both bulbs will light up despite using a modified sine wave inverter. If so, by how much? They're currently .1uF 400V.http://www.amazon.com/gp/product/B004FELHUO/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1Here are the 2 bulbs I'm using. LEDs are not an option unfortunately. The technology isn't there for UVC.http://www.lighting.philips.com/main/prof/lamps/uv/germicidal/tuv-pl-s/927902804007_EU/productIf there's something else I'm not considering please chime in.Thanks for the help!

author: Seekonk
author_rank: Super Contributor
timestamp: February 13, 2015, 02:06:20 pm
content: What photo of the circuit? Is this for septic sanitation? I would suggest a 120 to 15-24V transformer used in boost mode on the inverter. That will boost the peak line voltage to a normal 160 instead of the 140 found in most inverters.

author: Kjelt
author_rank: Super Contributor
timestamp: February 13, 2015, 02:22:39 pm
content: QuoteWhat is the temperature "out in the field" ? I am thinking that this might be the culprit, CFL's are notorious when it is cold (<5oC).When they are on for a few minutes they will stay on usually so if you are powering it from a carbattery you might try igniting them in the warm car, let them come up to temperature and then take them outside.For cold temperature there are special CFL's with a capacitive lint going right aside the tube, they are AFAIK not available in this particular version howeverIndeed the best option in cold environment is to buy a LED based lamp on 12 or 24VDC directly from the car battery.

author: ICSK
author_rank: Newbie
timestamp: February 13, 2015, 08:22:15 pm
content: Quote from: Seekonk on February 13, 2015, 02:06:20 pmCircuit photosNo, this is for field collecting of fluorescent minerals. That's why I wanted emphasis on portability. Unfortunately I won't have access to AC power as well. My lamp is just a standard worklight with UV bulbs put in. Then it is powered by a 13.2V LiFePo battery + inverter.Here's some eye candy to illustrate what happens when you put things under UV lightQuote from: Kjelt on February 13, 2015, 02:22:39 pmIndeed that's a possibility I considered and I do go regularly collecting at night in temperatures as low as -1C. However, I'm able to recreate this effect at home, leading me to believe that it's a problem on the electric side.Quote from: Kjelt on February 13, 2015, 02:22:39 pmI wish!!! If 250-260nm LEDs were viable I'd have made one. I hate working with bulbs! Last I checked (October? November?) it was $250 USD for a 10 mw LED from CrystalIS, the current leader in the industry.

author: Seekonk
author_rank: Super Contributor
timestamp: February 13, 2015, 11:36:58 pm
content: Looked at the picture. Does the AC go into a full wave bridge rectifier? couldn't see from the picture. I bought a number of defective inverters and I just ran CFL lamps and DVD players directly from 140V DC when the H bridge was shot. A little more efficient. If comfortable with the electronics, I would just increase the B+ sense resistor value so the HV to the H bridge increases 10-15V. That would be the lightest solution. I see two caps on the lamp board, is that a voltage doubler (only two rectifier diodes)? That would restrict you to keeping it AC.

author: ICSK
author_rank: Newbie
timestamp: February 14, 2015, 12:56:36 am
content: Ah how I wish the problem was that it was just a defective inverter... I've gone through a half dozen of these from 4 different manufacturers.Here's another set of images. The rectifiers are shown in Q1/2. Unfortunately I'm new to this and can not tell if they are full wave.http://imgur.com/a/NZIlgI also do now know what a B+ sense resistor is. I took a look on Mouser and none of the parts look like these:http://www.mouser.com/Passive-Components/Resistors/Current-Sense-Resistors/_/N-7fjcf