Multimeter won't read Lionel 80W transformer correctly

Could be because of the type of AC sine wave the Lionel transformer is producing. Is your Williams transformer an older full wave type, and is your K-Line volt meter car a needle type or digital read out?

I suspect the waveform of the transformer is fooling the meter, some meters only read AC accurately if it's a pure sine wave.

These results somewhat defy figuring out an answer.

The digital meter reads one of two ways, true RMS which would mean that your Lionel CW80 (?) is low on max output or not a true RMS meter which would mean that it reads 0.7 times peak of the waveform. In that case I would expect it to read near 18 vrms if the transformer is putting out what it should. So again, it would seem that the CW80 is low on full output.

The voltmeter car probably reads average volts so the faceplate on the meter is scaled  up by about 10 percent to indicate RMS voltage. This is not consistent with the digital meter at all.

I'm trying to think of a way you can look at the CW80 output without an oscilloscope to determine if it is working properly. One way would be to obtain two identical bulbs and compare the brightness of them, one connected to the CW80 at max output which is supposed to be around 12 rms volts by the meter and one connected to an 12 volt DC source which you can confirm with your meter which seems to read DC (the AA cell) voltage accurately. If the bulb connected to the CW80 is much brighter, then the meter is at fault. If they are about the same, then the meter is fine and the CW80 is at fault.

The K-Line voltmeter car is an analog meter. the Williams transformer is the AtlasO supplied transformer (newer.) What type of sine wave it produces, I do not know.

Thanks for the information guys!

What kind of meter do you have?  A cheap Harbor Freight one will read this way.  All my CW-80's read between 12 and 14 volt with my HF meter.  I think it's as John says, the funky wave of the transformer is fooling the meter.

I just checked my $10 clamp-on HF meter and my Fluke true-RMS meter on the CW-80.  The Fluke reads 17.8 volts, the HF reads 15 volts.

Try a dc reading. You should get zero, or just maybe a micro volt reading.

Any dc would indicate a rectifying issue or possibly a poor connection/cold solder joint

I think I figured out the solution! Watt am I talking about???

I had a couple early cheaper digitals that read voltage slightly off compared to a high end fluke. I noted the .75v and 1.2v per 50v ac difference was consistent, and proceeded to use them for years with that in mind. DC was fine

 Try making a "new" set of leads from some old wire just to see if there is a difference.

Ive been fooled with by my leads, even new.

I like making my own .  I have 6 wrapped around my meter at all times.

 A variety of lead types will make things easy.

There are times alligator clamps on leads, and clamp probes Ie"component legs grabbers" will save you frustration and time.

Lead probes can be sharpened and/or guarded with shrink tube to prevent shorting in tight areas.

I have one pair with sewing needles for the probes.

I can poke a wire to read off it easily, with little need for concern about exposing enough wire to need to tape after.  

I also thought the CW-80 only read a proper voltage when loaded.  So until powering a load such as several light bulbs to generate a current flow, the No load Voltage reading would be low.   G

With a true-RMS meter, the voltage of my CW-80 is 16.60 with no load, and 17.60 with a light load, my set of TMCC test boards drawing about .2 amps.  The line voltage here is around 125 VAC.

Gentlemen,

   You guys who like CW80 transformers are going to beat me up again, but what does it tell you about this transformer when a Multi-meter does not even measure it correctly.

Give away your introductory Transformer to a kid starting into our hobby, let him run small bumper Cars with it, and purchase at least a Z-1000 or bigger transformer to power your layout.

PCRR/Dave

Dave,

I couldn't agree with you more. I cannot understand why some insist on keeping and using starter transformers. At least the OP only uses his to power accessories.

Here it comes Dave.

The Z1000 with it's controller would suffer the EXACT same measurement difficulty, as it's also a chopped wave transformer.  I have both, they both measure similarly.

You haven't had the true starter set transformer experience until you try the 30VA PowerMax transformer.

The CW is a very versatile 5 amp power supply all in one convenient package.

I have a Z1000 and prefer the all in one package and feel of the CW-80.  Plus it runs my old MTH PS-1 locomotives better than the Z1000 does, IMHO.

Compare the output readings of a cheap DVM with the panel meter readings

of the ZW L transformer at all voltage levels. The ZW L panel meters give a true

RMS reading even though the output is a clipped sine wave at low voltages.

Rob,

You're correct. My first starter sets came with a Lionel Type V and early Lionel T Type w/Rheostat.

Stewart, there was an excellent article in the August/September 2013 OGR magazine authored by George Brown titled "Chopped AC" It was very well written and illustrated and I pretend to understand it. As I deal in "pure" 3 phase sine waves I have kept it handy as a troubleshooting reference. Truth be told, I only pretend to understand AC as a whole and know just enough to separate me from a light bulb salesman...

 The newest I have is the brick & grey dial from older starter sets. Its OK not great. Turn the dial too quick on a loaded pw Hudson or dual pulmor GG1 and it might faint. But if you act right, it works ok.

  I keep it around because its fast drop out feature ("breaker") has helped me find intermediate shorts in track easily!

  I power my #175 rocket pad with it now. Its next to the 175 controller because its the only thing Lionel made that you can put the grey dial next to and have it look like it might belong there.

 Full throttle being a good match for good match for my PW steam loaded, I've actually stepped back down to 1-100w marx, 1- 75w 1032, and 2-90w 1033s for the most part on my 4.5x9.

 With the right trains on the right transformer/track, I can flick the Lionel throttles to full and have them all run from prototypically fast, to moving at a good click above that but "safely".

 Lets see you do that with 100w or more.

 Bump a slow trains throttle? No big deal, its just an early arrival now, not a rollover.

 Still have to watch out for the Marx transformer. But those take a decent amount of pressure to turn too.

And marx and can motor engines! They're faster