Re: Locomotive current demands
- On Fri, 31 Dec 1999 22:52:42 EST, you wrote:
>From: BJKRONEN@...Bill and group:
>Jeffrey and Bim:[snip]
>>Jeffrey: I suppose I'm not quite clear on what we're checking here though.
>Who's next at the keyboard on this topic?Me! But I'm not at all sure, that my question is relevant in the
- What about the inner resistance of the ammeter?
Is it a specific relationship between inner resistance of loco and
ammeter that will produce produce the readings mentioned? And does the
loco resistance vary with rotational speed - so that you will get
varying milli-amp readings depending on the point where wheel-spin
sets in (wheels and tracks not beeing 100% clean and friction/weight
I guess everyone will see immediately, that I do not know a lot about
these things! But....?
BTW: the lights on my locos only turns on at a voltage where the
current consumption makes the loco rather hot?? (Marklin locos)
regards Ole Rosted, Denmark
- To Bill B and the list.
I don't remember seeing anything on whether or not the track should be
level, and would it be possible to use wheel slip at a specific angle?
I have my test track with a hinge on one end and a jack screw on the
other so I can see how a loco will do on a grade.
Have you or anybody tried using the "cheap" digital multimeters from
Radio Shack etc as the source of current reading?
Is there any place (database) that we could put our data into, and all
get at? Somebody that has a web site to act as a server, but I don't
know about having external data input to a database on the net. Don't
want to burden the web site owner with having to manually input
> I don't remember seeing anything on whether or not the track should beWe just kept it simple. Flat and level for the wheel slip current test. I'd
> level, and would it be possible to use wheel slip at a specific angle?
suggest computing grades may be more than some folks want to get involved
> Have you or anybody tried using the "cheap" digital multimeters fromYup, and its a problem. Digital meters sample the current a few times a
> Radio Shack , etc., as the source of current reading?
second and display the results. More you pay, more samples per second.
Problem is, there are a lot of variables and the digital meters tend to not
have a consistent reading, rather the numbers on the meter just bounce around
like you were playing roulette.
But good old analog meters tend not to do that, and the needle stabilizes on
a fixed point on the scale, so you can read it.
> Is there any place (database) that we could put our data into, and allWhat about the archives of the OneList itself? There are a number of folders
> get at?
*** Jeffrey MacHan: How does that work, list owner? ****
- Sorry if dredging up ancient history offends anyone ...
--- In email@example.com, Dec 31, 1999, 9:52 pm,
> Jeffrey and Bim:
> >Jeffrey: I suppose I'm not quite clear on what we're checking here
> There are two nightmares you can have with any model train in any scale:
> 1. Burn out the motor (with too high a voltage, or some types of
> 2. Have a dysfunctional mechanism that gives you frustrating
> overloads the motor until it burns out, or tears up the gears.late.
> The question at hand addresses the detection of # 2 before it is too
A goal to which I aspire most vigorously!
> > Bim: What do you use to measure current???expressed in
> Most folks know that a volt meter measures electrical pressure
> volts. In order to make that measurement one puts the meter inPARALLEL with
> the power pack, the rails or the loco.the power
> In order to measure current, one has to put a meter in SERIES with
> pack. Since the polarity of the power back can be reversed, a "zerocenter"
> meter is appropriate. That means a meter that at rest, will haveits pointer
> in the middle of the scale, and not off to the left side like mostmeters. A
> meter with 1amp-zero-1amp offers a usable reading, but can survive adead
> short across the rails. Remember, any current (including a short)will pass
> through the meter on the way to the rails in a series connection.Again, because
> Likewise, a "zero center" voltmeter is quite appropriate too.
> the power pack can reverse the polarity to the rails.together a
> If interest develops, any one of several of us on the list can put
> list of parts from common (cheap) resources that folks can buy anduse, with
> little or no electrical knowledge. A number of how-to books alreadyhave
> this information.What I would like to do is set up dual meters (Volts & Amps) for each
> But let's see if anyone agrees with the "normal" readings and the "test
> procedure" before we advance to that step.
> Who's next at the keyboard on this topic?
> Bill Kronenberger
of my power packs, or integrate the meters into a Z Bend Track control
connecter. Where would I get the information as to parts & assembly
for this project?
John L. Battey in Roanoke, TX