Hello, I bought a used CW80 and decided to test it. With a 12 volt bulb for a load I get 15.5 volts at full throttle. On a 12x16 fastrack oval with an engine running wide open I get about 13.6 volts. The bottom of the transformer says 18 volts output. The accessory side shows 7 ish volts
Am I missing something?
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Yep, you're missing the fact that most inexpensive meters can't accurately measure the voltage from a chopped wave transformer. The CW-80 is also a special case, it's output waveform is one of the ugliest ones I've ever seen!
There's a cw 80 voltage conversion chart for "regular meters" on this old thread. According to this chart your getting 18v:
check to see if your meter says "RMS" anywhere on the case. most inexpensive meters do not read 'R'oot 'M'ean 'S'quare (RMS) voltage - those that can read it are proud of it and print it on the meter case or maybe hiding in the model number.
It's been my experience that many meters that claim to measure RMS voltage don't really do it accurately.
How True is your True RMS Voltage?
I use my 'scope to measure True RMS if I really want to know the value. The 'scope samples hundreds of samples on a single waveform and computes the True-RMS value.
Thanks all. Explains why my other transformers show 18+V.
@gunrunnerjohn posted:
Nice. Was like going through old 'lab notes' from trade school 
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