Power supply

The absolute maximum, at least according to most user's manuals, is 19V.  That would be the RMS value.

Thanks for the info.  I think I'll just pick up a brick at one a local show this weekend.  I'd rather not chance the 21.5V levels.  

Btw, can you please reiterate the placement of the TVS's once again.  For the life of me, I lost the link to a thread I had a while back.  I'm using fast track.  Do I put one TVS at the power supply terminals and another one anywhere power drops attach to the track?

Thanks a bunch.  

Just put them right across the track feed.  In truth, the closer to the item being protected, the better the protection.  That being the case, I'd put them at the track across the power feed.

That is out of spec for this toroidal transformer...

http://datasheet.octopart.com/...tasheet-21265007.pdf

The data sheet says 8% no load to full load. How did you arrive at 21.5 volts?

Usually transformers are rated at a specified load.  I would put the rated load on the transformer and then measure.  Same thing for wall warts. 

For use with TMCC/Legacy, that's not actually a truly valid measurement.  You need a light load, but if you run a small TMCC powered locomotive or motorized unit over the section, it should still not be more than 19 VAC maximum.  If I were to apply the "rated load" standard to his transformer, it would doubtless seem suitable for TMCC, in truth it probably isn't.

Yes, good point. Seems like many power companies run on the high side. Sells more power?

There is a 50KW transformer out by the street that just supplies my house, and my power routinely runs on the high side.  It's actually running low right now, 124 VAC, but I've seen it at 129 VAC at times.  Since both sides of the 220 measure high, I'm assuming that it's really just running pretty high.  There is a substation less than a mile away, so my power doesn't have to come very far.

Yea regularly at my house in western NY state I get approximately 123V AC for power.   I was surprised in a somewhat disappointed way when I noticed that.  I moved about 30 miles a couple years ago from another location and never remember receiveing voltaged exceeding 120.   I loaded down the output of the transformer with about 3A using some power resistors and under load the output of the transformer will drop accordingly to about 18V AC.  Doesn't seem worth it to me to run a mini space heater, along with the trains, although we are supposed to get some snow this weekend.  

Regarding the 21.5V original reading, that was with a handheld DMM on a 200V scale.  since the measurement overranged at 20V, I had no choice but to bump the scale to 200V.  So 21.5V was measured on a 200V scale. Probably not all that accurate, but it is what it is.  Thanks everyone.

I thought some years ago it used to be 10%, but I've never seen over 126 or so at home.

The school used to run 208/120 (3 phase). That was a pain at times.

MoogGuy posted:

Yea regularly at my house in western NY state I get approximately 123V AC for power.   I was surprised in a somewhat disappointed way when I noticed that.  I moved about 30 miles a couple years ago from another location and never remember receiveing voltaged exceeding 120.   I loaded down the output of the transformer with about 3A using some power resistors and under load the output of the transformer will drop accordingly to about 18V AC.  Doesn't seem worth it to me to run a mini space heater, along with the trains, although we are supposed to get some snow this weekend.  

Regarding the 21.5V original reading, that was with a handheld DMM on a 200V scale.  since the measurement overranged at 20V, I had no choice but to bump the scale to 200V.  So 21.5V was measured on a 200V scale. Probably not all that accurate, but it is what it is.  Thanks everyone.

Since it's a sine wave, probably accurate. Can you pull a few turns off the toroid if the output is on top?

Maybe I should complain.  One issue we have here is standard incandescent bulbs have a much shorter life than most folks experience.  Seeing LED lighting come along has really saved me money in more ways than one.

So I take it that the LED lighting is not bothered by the over voltages like the old 120v incandescent bulbs? We switched to all LEDs except for a few CFL's left in the basement. Those are getting LEDs as they fail. LEDs have been in service here for a little over 3 years, no failures yet.  

Years ago we used 130v light bulbs which lasted a lot longer, but are hard to find now. I usually only see rough service bulbs in 130v these days, which cost quite a bit more and are also becoming a bit scarce.

I used 130V floodlights in my outdoor lights as they're pretty difficult to replace, being around 20 feet or more up!  If they ever get replaced again, they'll get LED replacements. 

gunrunnerjohn posted:

I used 130V floodlights in my outdoor lights as they're pretty difficult to replace, being around 20 feet or more up!  If they ever get replaced again, they'll get LED replacements. 

The LED 75 watt  floods/spots are available either 26 degree (Spot)  or 40 degree (Flood) 10 to 12 watts.  Note that exterior use should be damp location approved.  I also replaced the 100 watt Mercury lamp, dusk to dawn front yard post lamp  with a 100 watt equivalent LED.  Note that the Mercury lamp and associated equipment (Ballast) had to be removed before the LED lamp was installed, photo control remains.  

Specialty lamps 50 watt R20 that I use over the train layout are also available.  500 lumens 7 watts.   

Most of the incandescent upgrades, I'm seeing a 6 to 8 times savings. comparing watts.   The new lighting is better, more light,  than I had previously with the incandescents.  It was amazing how many lamps there are.  

The Home Depot lamp display continues to change with additional specialty lamps available.  

You may want to try some of the 40 watt equivalent lamps.  They seem to work fine for us.  As noted there is a difference related to dimmable.   Also there are warm and soft light colors.

I haven't figured the total cost, there were three or four purchases.   Estimate $7 per lamp X  50 lamps or more. 

I have yet to change any flourescents.  I will probably change the fixtures, or go with retro-fit kits that seem to available for some of the recessed fixtures.     

Yea cjack- output winding is on top. minus a few turns, output voltage is safely at 19V now. Input voltage is 121V AC today.  So at the moment i'm dialed in to 19V at the output in an unloaded state with likely what will be a near maximum input to the transformer given the service in my area.  The other day I did see 123V but that's as high as i've measured since I started checking.  

I could probably remove another 1/2 turn to get a tad below 19 just to be safe.  Looking good though.

Thanks. 

Great. 

There are no half turns. If the wire goes thru the center of the toroid, it's a turn. But one more removed  is probably good. Don't cut the wire, before you're satisfied with it.