Now I have found a 7.5 V 1.5 amp transformer.
From my earlier post/question on the topic I know that the 12 v and even the 6 V transformers I have will work ok...but those were both around 200 mA.
Ques: is 7 V 1.5 amp too much amperage to attach to the tortoise?
Thanks.
Not at all. Again - the amp rating of a transformer or power supply is NOT how much power it will PUSH into a deivce - it is the limit on how much can be PULLED from the power supply. 1.5 amps should be good for about 80 Tortoises.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
Yep, Randy is right.
Elmer.
The above is my opinion, from an active and experienced Model Railroader in N scale and HO since 1961.
(Modeling Freelance, Eastern US, HO scale, in 1962, with NCE DCC for locomotive control and a stand alone LocoNet for block detection and signals.) http://waynes-trains.com/ at home, and N scale at the Club.
Keep in mind, though, that if it's not a regulated power supply, the voltage will be higher the more lightly it's loaded.
In other words, if it's an unregulated supply rated for 7v AT 1.5 amps, but you only load it with only a few milliamps from a tortoise or three, it might be put out 10 - 12 volts or more.
Which is all still fine, since Tortoises are rated for 12V.
rrinker Not at all. Again - the amp rating of a transformer or power supply is NOT how much power it will PUSH into a deivce - it is the limit on how much can be PULLED from the power supply. 1.5 amps should be good for about 80 Tortoises. --Randy
Thanks for the new knowledge....amps being pulled I mean.
So, even if the transformer is unregulated and attached to one tortoise, the tortoise will only pull the right amount max 12 V from the extra voltage available from an otherwise7V device.
Well, Volts ARE 'pushed'. If the supply is delivering 14 volts then the Tortoise is goign to see 14 volts.
I seriously doubt a 7V power supply, even unregulated, is going to produce 14v with a light load. It will certainly be higher than 7V. The difference with a regulated power supply is that typically a device known as a voltage regulator (quite original name, huh?) controls the output voltage and dissipates any extra, generalyl as heat, so even with a very light load connected, 7 volts comes out. Up to the limit of the regualtor - many common ones provide a sort of self protection, they shut down when they get too hot from too much load.
For things like fancy electronics - like your computer - proper voltage levels are critical. For things like the Tortoise, it's not really necessary to spend more for a regulated power supply. Theyhave a wide range of operating voltage so as long as the power suppyl does not exceed the maximum voltage and doesn't drop below a reasonable minimum (I'd say around 5-6 volts, much lower and it might not have enough force to hold the throwbar in position when stalled), it will work just fine.
rrinker I seriously doubt a 7V power supply, even unregulated, is going to produce 14v with a light load. It will certainly be higher than 7V.
I agree. But if I'm not mistaken, the OP's other thread on the subject indicated he might have wanted to use a lower-voltage supply to slow the Tortii down. If that's the case, he probably won't see much of a slowdown unless he loads up this supply with a whole bunch of them!
This is where one of those cheap meters would come in very handy - Take a no-load voltage reading of the supply and you know exactly what you're working with.
Thanks guys. It's humbling to see all the ink spilled/keys punched merely because I am rooting through a drawer full of old power supplies rather than drive down to the city to buy exactly the right one (which would be a 9V if I do),
So I do have my choice of a few old ones ranging from 5.5, 6, 7, 12 V. 180mA to 1.5 A.
Thanks for helping me along. Now you have me curious enough to get one of those cheap meters to test an unloaded power supply, just to see what is coming out.
The 7 V 1.5A one is from a wireless router. It may be regulated huh? Seems to be a very big unit (physically).
Why not wire things up so it's easy to change supplies, and just test out your various possibilities. I don't think any of them will burn anything out, and you might find that you already have just what you need.
Jeff But it's a dry heat!
Cisco KidThe 7 V 1.5A one is from a wireless router. It may be regulated huh? Seems to be a very big unit (physically).
If it's from a router it may be a switching power supply, which by default would be regulated.