I have an old Pulse Master 1 transformer by Model Rectifier Corp that I've had since the early 1980's. It still works and there are no frayed wires or anything, but my question is whether this will be OK to power the scenery lighting on my layout or am I at risk of blowing out the bulbs? The transformer has a separate set of terminals that are labeled "Accessories - AC" (these are separate from the terminals labeled "Track"). I presume I use the accessory terminals for the scenery lights. Do I need anything with the lights to regulate current (obviously I really don't know what I'm talking about), or can I just hook the wires from the lights up to a bus wire and plug it in? The electrical information is listed as:
Input: 120VAC 60HZ
Output: 15VDC 17VAC
Total Output: 7.5VA
Ultimately I will be using a separate power source for the track.
Thanks all
It really depends on what voltage your lights require as to whether or not you will blow them out. You did not state their voltage requirements, so there's not really any way of knowing. Another consideration is to make sure you don't overload the transformer with too much amp draw. So we can help better too, if you advise of the number and amperage of bulbs as well as how they are wired--parallel or series?
One thing you can do if you can't find out the voltage of the bulbs. Attach them to the variable or "track" terminals and very slowly and carefully move the throttle up. If the bulbs are pretty bright very early on, they are likely low voltage 1.5V, maybe 6. If you have to go all the way up to say 15V, then they are likely 12, 14 or 16V. Be careful doing this because you can blow them out.
Richard
Thanks Richard. To try a few things out I picked up a cheap set of Model Power economy lights, the package indicates "12-16V No. 492". I hooked them up to the transformer and the they are bright with the throttle on zero, and moving the throttle up does not change the brightness. (EDIT: I didn't read your post closely enough and I hooked them up to the accessories terminals - I can try it again...)
I will be wiring them in parallel (I think I have the term correct)....each light connected separately to a set of bus wires that is dedicated to scenery lights.
In the short term I plan to have 4-5 of these lights. Ultimately it will be somewhere around 20-25 lights.
The AC Accessory terminals have been on DC powerpacks for years, mainly for powering the oldstyle twin-solenoid switch machines. For layout lighting (structures, streetlights etc.) full AC power is going to be very bright and burn the lights out a lot quicker than using lower voltage DC. I use an old MRC power pack for my lights, and I usually find running the bulbs at around half power (6 volts or so) makes the streetlights etc. look more realistic and makes the bulbs last for a long time.
Looking at the specs, this unit will only deliver about half an amp. I use a lot of Miniatronics grain-of-wheat bulbs on my layout. I prefer the 16-volt ones, and I run them at 12 volts to extend bulb life and provide a nicer glow rather than a bright light. These bulbs draw about 30 milliamps each. If you were to run your supply right on the edge, which wouldn't be recommended, you'd only be able drive 16 of these bulbs. It sounds like a lot, but once you start with building lights and street lights, they add up quick. The last structure I built has 7 or 8 bulbs in just that one building, and it's not very large.
I'd recommend going out and getting a heftier power supply for your layout lighting. All Electronics has some 5-amp, 12-volt supplies for around $20. Get a fuse block and some 4-amp fuses for it, and it will serve you well. These low-cost supplies do not have circuit breakers, and they come with a one-time fuse to keep from burning down your house, but once that fuse goes the supply becomes a candidate for recycling.
It takes an iron man to play with a toy iron horse.
Radio Shack has 12 volt power transformers, in several amperages, which are useful for layout lights and switch machines. Also, you can pick up old power packs cheap at train shows.
Radio Shack also has a 25V pot (potentiometer) you can use to control / reduce the output of a power supply. They also sell knobs for it, and you can put it on your control panel or pick up a Radio Shack project box.