Texas Zepher richhotrain: Texas Zepher: If one is going the DC route get the most pure filtered DC power supply availalble. TZ, when you say to get the most pure filtered DC power supply available, what exactly does that mean? If the MRC Railpower 1370 power pack such an animal? When AC current is converted to DC the most simple process (a bridge rectifier) just takes the normal sine wave and flips the negative half of the cycle to be positive. It basically makes a set of humps where the voltage goes from zero to the max voltage at 2x the frequency. In the USA all power is 60 cycles per second so a straight conversion results in the power going from zero to 12V 120 times a second. On the other hand a battery produces a true flat line voltage at 12Vs. A battery could be considered a pure filtered DC. One way to smooth out the voltage from a straight bridge rectifier is to put a capacitor on the DC output. As the capacitor charges and discharges it tends to fill the gap between the humps in the rectifed DC power. Unfortunately I do not know anything about the MRC Railpower 1370 other than it is has a full wave rectification. I did find this post from a few years back about the MRC 1370 --> http://cs.trains.com/trccs/forums/t/29520.aspx
richhotrain: Texas Zepher: If one is going the DC route get the most pure filtered DC power supply availalble. TZ, when you say to get the most pure filtered DC power supply available, what exactly does that mean? If the MRC Railpower 1370 power pack such an animal?
Texas Zepher: If one is going the DC route get the most pure filtered DC power supply availalble.
If one is going the DC route get the most pure filtered DC power supply availalble.
TZ, when you say to get the most pure filtered DC power supply available, what exactly does that mean? If the MRC Railpower 1370 power pack such an animal?
Unfortunately I do not know anything about the MRC Railpower 1370 other than it is has a full wave rectification. I did find this post from a few years back about the MRC 1370 --> http://cs.trains.com/trccs/forums/t/29520.aspx
Thanks, TZ.
Alton Junction
richhotrain Texas Zepher: If one is going the DC route get the most pure filtered DC power supply availalble. TZ, when you say to get the most pure filtered DC power supply available, what exactly does that mean? If the MRC Railpower 1370 power pack such an animal?
will give it a look thanks
It may very well be fried, but before you throw it out look at it carefully. Some wall warts have a fuse in the plug. If not, some plugs can be disassembled. It may have just burned a wire.
Dave
Lackawanna Route of the Phoebe Snow
i do have an old walwart charger from something, it says it puts out 12v@800ma OK?
i had a 1500ma RS walwart but when hooking up one of the leads to a junction block i shorted it out and was told the walwart wasn't any good anymore, no reset button and no automatic reset i believe i fried it, so i was told by a RS employee
A Tortoise at full stall only draws 18ma. 18ma times 16 Tortoise motors equals 288ma. 500ma is more than enough. I have a 15VAC wall wart with 850ma capacity(Old cordless tool charger). I use a pair of diodes to make a split power supply like the example in the Tortoise instructions. I get about 9VDC half wave for my Tortoises to power my 30 Tortoise motors - more than enough power.
Jim
Modeling BNSF and Milwaukee Road in SW Wisconsin
Given that a tortoise uses 30ma at 12 Volts. A 12 volt supply would need 16 X 30=480ma Max so a 500ma will be sufficient.
Alan Jones in Sunny Queensland (Oz)
what size walwart for 16 tortoises' 500ma 800ma 1500 ma thanks
Since the Tortoise motors stall at the end of travel, if the DC isn;t filtered they will tend to amplify any AC 'buzz' that comes through. Two ways to reduce this are to lower the voltage (they don;t really need a full 12 volts to oeprate well - 9V works good, or 12V with some series LEDs for indicators) or to filter and smooth out the DC power to it truly is smooth (as close to a battery as you can make it). The Railpower power pac is not filtered DC. Very few DC power packs filter the output, because the slight variation int he unfiltered DC helps start and runt he loco's motor at a slower speed. Taken to a more extreme level are the power packs which deliberately add in an AC pulse component for pulse power. Super sophisticated pwoer packs DO use filtered DC and then inject a variable AC pulse for starting.
ANyway, with respect to a Tortoise, the quietest operation would be from a well-filtered power supply, but a more simple one isn't going to hurt them. Try running a Tortoise on a 9V battery - pretty quiet despite the dozen gears in the internal gear train.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
Texas Zepher If one is going the DC route get the most pure filtered DC power supply availalble.
I use MRC Railpower 1370 power packs as the source for all of my Tortoises. I have four of them evenly distributed throughout the layout to power 60 Tortoises.
Rich
KHM60 can you power a tortise with an AC and if using DC does the switch have to have a center off position
can you power a tortise with an AC and if using DC does the switch have to have a center off position
In fact, in over 25 years of using stall motors for turnouts I have come to prefer the AC power method. Why? Because if one wants to control a turnout from several different locations it only takes one wire from each of the locations directly to the turnout. This might not sound like much but consider the situation where one has a massive yard with multiple control panels for it. Each panel can control the turnouts indpendently. One does not have to run two wires for each turnout between each panel. I tried that once - not fun. The panels do not have to be the same type. I have mixed panels with traditional SPDT with single button route diode matrix type. Way cool.
Someone will be sure to point out that the tortiose is supposed to have constant power, but this has not been a problem. When I first installed a trial system using this manner of control not one operator noticed it. There were zero instances of point creep. I might even be leary of putting constant power on them, because as someone else already pointed out it would be half wave power. That could cause heating issues. If one is going the DC route get the most pure filtered DC power supply availalble.
LOL That's what I thought.
But, I had a part time job flying line patrol for Niagara Mohawk Power company years ago. I have actually seen 100 KV lines.
Phoebe Vet Are you positive that you don't mean 100 KW ?
Are you positive that you don't mean 100 KW ?
Right. THAT is what I mean.
The Route of the Broadway Lion The Largest Subway Layout in North Dakota.
Here there be cats. LIONS with CAMERAS
Phoebe Vet 100KV generator ? Do you power it with a hydro dam or a coal plant?
100KV generator ? Do you power it with a hydro dam or a coal plant?
Actually, it is Diesel powered. Our primary boiler is coal fired, our old #1 boiler does not pass inspection any more, and I am not sure we will put any money into it. We just installed a new gas fired back-up or summer boiler. It has more rated HP than the coal boiler, but burning coal saves us about $200/day on our heating bills.
Once upon a time (think 1910-1920) we *were* the power company for the city of Richardton.
In the 20s MDU came in with real, genuine AC power, but we kept our DC running into the 1960s, albeit we also used AC from MDU.
I was looking at the breakers up on the power pole on the street. 100Amps each... But then that is on the 4000 volt side of the transformer ☺
Presently our normal power loadings are about 20-25 KW; but on Sunday when the church is all lit up loadings go up to about 45-50 KW.
ROAR
LION powers his with AC current which passes through TWO transformers to drop the voltage to 12 vac, and then passes through TWO rectifiers, so that I have THREE wires out. One wire is (+)12vdc; the second wire is (-)12vdc, across these two conductors is 24vdc. The third conductor is ground, and that is HEAVILY grounded to the building ground system. (ask me to show you THAT sometime!--This ground conductor follows around the entire layout.
In my switch control machine there is both +12vdc (Green) and -12vdc (Red) Single pole double throw (micro) switches select one or the other with the output on the switch common.
This output controls panel indicators, the switch machine, any wayside signals connected to the switch machine, and any extra relays for routing track power or local signal logic as may be required at that location. ONLY ONE WIRE connects the control to the controlled.
In case of power failure we have a 100KV generator on a five second standby.
And you thought *I* could make a simple railroad! HA!
rrinker ANd here we go confusing people about electricity again, no, he does not need a DC power supply he can use his AC supply and a couple of diodes. No center off, that is correct. --Randy
ANd here we go confusing people about electricity again, no, he does not need a DC power supply he can use his AC supply and a couple of diodes.
No center off, that is correct.
Randy,
What I am saying is that, for the OP's purposes, it is best to advise him that a DC power supply is the answer for him.
I don't know the OP, but I would bet that he doesn't even know what steering diodes are. I was merely trying to simplify things for him.
Geesh, for such a simple initial question, this thread has really gotten contentious.
Yep, when all is said and done, what the OP needs to know is that he needs a DC power supply and that a Center Off switch is not necessary.
It's still an AC pwoer supply powering the 'system' when using the steering diode method.
Never a bunch of people more caught up in semantics than model railroaders. OK, what EXACT technical details, the Tortoise motor uses DC only. But you can control them from an AC power supply using steering diodes. All the non-DCC controlled ones on my friend's layout operate this way with a 12V AC power bus around the perimeter of his layout.
" Since the system is supplying only half-wave DC, the voltage of the transformer should be 14 - 16 volts to compensate."
I rest my case.
"Misleading"? Surprised folks want to argue a simple point. The Original Poster asked about AC as if he had an AC power supply available and hoped to use it. The Circuitron documentation offers a way to use AC.
I merely pointed that out.
Layout Design GalleryLayout Design Special Interest Group
KHM60 what is a wall wart
what is a wall wart
Circuitron offers its own wal wart to power the Tortoise. Scroll down to the bottom of the page on the link:
http://www.circuitron.com/index_files/Tortoise.htm
Phoebe Vet cuyama: KHM60: can you power a tortise with an AC Yes. You must add diodes with AC. That is misleading. What you have actually said is you can use AC if you use a diode bridge to change it to DC. The tortoise operates on DC only.
cuyama: KHM60: can you power a tortise with an AC Yes. You must add diodes with AC.
KHM60: can you power a tortise with an AC
Yes. You must add diodes with AC.
That is misleading. What you have actually said is you can use AC if you use a diode bridge to change it to DC.
The tortoise operates on DC only.
We may be arguing semantics. Here is what Circuitron, the manufacturer, has to say:
3. AC WITH STEERING DIODES: This system utilizes a standard AC Transformer in conjunction with two diodes to provide half-wave rectified DC to the switch machines. One side of the transformer output feeds a layout bus wire as in (2) above. The other lead from the transformer is connected to two diodes, each of which then powers a panel bus which is connected to the SPDT switches. Note the polarity of the diodes. Only one wire runs from each panel switch to the respective TORTOISE. Since the system is supplying only half-wave DC, the voltage of the transformer should be 14 - 16 volts to compensate.
cuyama KHM60: can you power a tortise with an AC Yes. You must add diodes with AC.
Wall Wart = Plug pack = power transformer with mains pins so it plugs into a mains outlet at the wall. kinda sticks to the wall = wall wart . alogical huh!
A wall wart is that ubiquitous little device that plugs in the wall to power everything from TVs, to computers, to appliances. You can find one to me your specific requirements and trim the end of the wires to connect to your device.