fl inverter fyi

[deerslayer660]

   hi again all i just removed 10  8ft shop lights from a building thats being torn down 2 of witch i droped wile removing ceiling was real bad and they fell when i touched them came unpluged and hit the floor .So i thought these would be good to make a 12 vdc light for shop so

 took the best of the two with was probly still ok and removed the ballest next i unhooked the wires from tube ends than i wound two transformers  from the previous posts on this. I was going to just install the parts right on ends of the transformers but used perf board instead i used 2 ckts one for each tube and tried

useing light as heat sink used insulators on bolth transistors and this did  not work only one tube will light and some what dimmer than normal the tube that does not light will damage its transistor afetr killing a few transistor i thought that the transformer was bad and took another that i had made that i knew was good and installed it. again tube not lighting but at least i did not blow this transistor

so i checked my ckt again for mistakes and there were none! ready to pull my hair out as a last ditch effort i removed the transistor from light housing and installed it on a seperate heatsink applied power and bolth tubes on  bright so i used a peice

of 1x4 wood screwed to light than screwed heat sink to wood now insulated from light

oh yea all this is inside light ware ballest was . light draws 3.4 amps with 40 watt tubes. running 6 hrs now with no troubles i think i will try this one more time but i will only use 1 ckt and 2- 25 watt tubes in searies to try and get amps down to around 1.8 anyone tried this? i have plenty 40watt tubes now but no 25 watt i will have to buy these so anybody that thinks this wont work let me know befor i waste

my $   oh yea i am using tip3055 transistors with install kits to light housing and wires running to perf board    george

 have fun  george

 

[deerslayer660]

 I schould have said that i left one transistor using the light housing as heat sink and one insulated with the wood if using only one ckt the light housing schould be a fine heatsink  george

[PaulM2]

To run my dual 40w tube fixture it took about 8 amps with my 120vac inverter, so I'd say if you have full brightness at 3.5a you're doing good.

[RP]

The heatsink tab on a 3055 is electrically connected to the collector of the transistor.  Go to RadioShack and get an insulating kit for that style transistor (TO220?).  It'll consist of a paper thin electrical insulator that's a good thermal conductor and a little plastic shoulder washer and screw set that prevents the mounting screw from connecting to the tab.  With this you can mount it directly to the fixture.

Hope this helps

rp

[deerslayer660]

  yea i was useing insulator kits on bolth transistors as i thought that was the problem but it did not work till i used a different heat sink