Using a multimeter I only measure ~16V at full throttle. I thought it is supposed to be ~18V ? Is it defective or is there a setting that should be changed?
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Whats the input voltage?
It's the meter.
https://ogrforum.com/...ransformer-correctly
@ADCX Rob posted:It's the meter.
https://ogrforum.com/...ransformer-correctly
The GW 180 has a 180w brick as its powersource. These are pure sine wave transformers on their own
Does the electronics for the variable power via the throttle handle change it to chopped?
@RickO posted:The GW 180 has a 180w brick as its powersource. These are pure sine wave transformers on their own
The CW80 has a 7-8 amp brick/transformer as its powersource built into the case. These are pure sine wave transformers on their own(and, incidentally, very useful for other projects when the CW80 electronics give out).
@RickO posted:Does the electronics for the variable power via the throttle handle change it to chopped?
Yes.
Thanks for the lesson Rob!
If I understand correctly, it is to be expected that a digital multimeter will read ~16V when measuring a Lionel GW-180 at maximum output (~18V) because of the characteristics of the sine wave output?
Remember that chopping is used to reduce voltage from the maximum put out by the brick. When the throttle is at 100% there should be no chopping.
Yes, most digital multimeters have a problem with chopped sine waves. You need one that measures AC using "True RMS" in order to get an accurate reading for any chopped waveform.
However, if your throttle is at 100% there won't be any chopping, the waveform will be a pure sine wave, and a cheapo digital multimeter should read the voltage correctly.
Perhaps when the throttle is set to 100% (physically) it's not really at 100% (electrically) and some chop is getting through?
Alternatively it might be the brick. Unplug the brick from the controller and measure AC at its output plug. Again, this will be a pure sine wave because the controller is not in the circuit at this point, so a low cost multimeter should read the voltage correctly.
(Also remember that you may not be able to do so with a recent vintage brick, i.e. made in the last couple of years, because the new ones have a safety interlock in the connector that cuts power from the brick when it's unplugged.)
Mike
I had the same problem with the BW transformer that came with a Santa Fe set back about 20 years ago. Thought I was losing voltage, but learned (was told) the apparent drop was due to my dime store multi-meter not recognizing the chopped sine wave.
