I didn't want to 'highjack' the thread on power supplies; but that dialog gave me an additional question. I run The Monks' Island Brewery/Railway with a DC handheld controller (Canadian made Jim). This controller, which is an excellent item, uses AC for power. As it now stands I used an MRC Tech II power supply (actually only the AC terminals on the MRC). This results in a rather large unit that takes up a lot of bench space for only its AC output terminals...'gotta be a better way.
I have checked all the 'wall warts' I can find and they all produce DC power only. Does anyone know of a fairly inexpensive AC-producing unit that is capable of outputting 12 - 18 volts AC; or am I stuck with using a complete model railroad power pack?
In keeping with the Forum's rules I will not mention the manufacturer of this throttle. Should you desire that information - contact me offline.
Cheers,
Ray
How about 16 vac 1.2 amps?
http://www.allelectronics.com/make-a-store/category/815/Wall-Transformers/1.html
Other possibilities. A search for wall transformer seems like a better search.
http://www.google.com/search?pz=1&cf=all&ned=us&hl=en&q=wall+transformer+16vac&btnmeta%3Dsearch%3Dsearch=Search+the+Web
Rich
Dear Ray,
http://www.bachmanntrains.com/home-usa/products.php?act=viewProd&productId=209
I have these wall-wart transformer and controller (power pack) combos new from set break-ups.
Contact me PM (click on my name - personal message) for more details.
There are two ways to get the wall-wart transformer's 16V AC, 1 Amp output:
1.) Non-protected directly from the transformer output plug, or
2.) Circuit-breaker protected (1 amp) through the two Push-Insert (wire)-Release terminals on the controller.
The only way I would use method 1 would be if I were certain there was circuit breaker (or some other form of current limiting) protection on the input of your throttle.
Again:
You must have/use some form of current limiting device...
The transformer itself does have an internal non-replaceable fuse, but if you blow it, you toss it in the recycling bin for its copper content....
Hope this helps.
Sincerely,
Joe Satnik
I sincerely appreciate the input to my thread's question. RichG, I checked out the websites you suggested and found at least a couple of wall transformers that would (on the surface) work for my application. What troubles me is the statement that warns about power fluctuations: [sic. 'output depends upon demand. At no to lower levels of demand voltage output is greater than specified (16 VAC with little or not load can approach 20 VAC); while higher demands lower the stated output (16 VAC can become as low as 10 VAC under certain conditions)']. According to the specification sheet, for the handheld throttle, voltages must remain in the 12 - 18 VAC range.
I would assume the same thing happens when connected to the AC terminals on my MRC Tech II power pack (ie voltage fluctuation vs demand). Fortunately I have an acquaintance with a retired aero-space electrical engineer and will run the problem past him. Before I do so (or order a wall transformer) I have to determine the power demands of my Bachmann MDT and Trackmobile.
Thanks again to all. Joe, I appreciate the offer of the controller/transformer sets...I have an excellent handheld throttle. Your caveat on making sure there is over current protection is a good one and will be followed.
Regards,
Ray
An AC wall wart will not have regulated voltage. It all depends on the amps the xfmr can supply before the voltage level begins to drop some.
A xfmr that supplies 200 ma and you draw 150 ma, the voltage will drop some. A xfmr that can supply 3 amps, the voltage will not drop much with with a 150ma load. Ohms law.
Some DC wall warts are not regulated. Some DC wall warts are regulated.
Rich
Ray,
How many amps max does your hand-held draw?
Voltage output @ Current draw measurements from Bachmann wall-wart transformer (nominally 16V AC @ 1 amp):
17.08 Volts RMS~ @ 0 Amps (open circuit)
16.3 Volts @ 0.466 Amps
15.8 Volts @ 0.684 Amps
15.3 Volts @ 1.093 Amps
Secondary winding resistance (DC) ~1.1 Ohms.
Internal impedance (estimated from first and last measurements above) ~ 1.6 Ohms.
Model:
l-------------------1.6 Ohms Imp.-------->
l
17.08 V RMS ~ Secondary Output
l
l----------------------------------------->
Hope this helps..
Sincerely,
Joe Satnik