Alternator Ac Ripple Testing On An Alternator

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Welcome to another Diesel Training Tech Tip where we dive deep into the world of diesel technology! Is your alternator giving you an electrical headache and your not sure what to do? Today’s tech tip will transform the way you use a scope to do a ripple test on an alternator. Michael Eilbracht from Diesel Training breaks down this simple but effective techniques. The small Ripple of hitting that subscribe button will make a big wave!

[@fernelyspacheco8776]

Exelente explicación saludos desde Colombia 🚜en el camino del conocimiento, gracias a diesel laptops y todo su grupo de trabajo con el sueño de poder adquirir sus productos y todo ese valioso conocimiento para aplicarlo y compartirlo 🙏🤝

[@hddm3]

Nice. Always making it easier for us Mike. Thanks

[@wentzelnel7723]

Good as always

[@MechanicTechnicianRepair]

Experience diagnosis master mi respect para ustes master

[@Steve.191]

Great video thank you 👍

[@DavidGutierrez-zi4dy]

THANKS!!!

[@paulw2791]

Thanks Busjockey!

[@kevinedward1234]

Mike, great video and info!!

[@user-zr5qi8hi8m]

Love it great content guys

[@jethro983]

Pulsating DC voltage.

[@bartscave]

What is a general rule for ripple limits?

[@mjediagnostics9510]

Usually no more than .5 volt peak to peak. That's industry standard. However there are variables. I recommend getting known good readings for every model and saving it.

[@jethro983]

You mention that it is AC ripple. I don't think so. It should be DC ripple.

[@DieselLaptops]

Good afternoon! We did mean to say AC ripple. Remember, alternators create AC voltage internally, then that voltage passes through a rectifier bridge to filter the AC voltage into DC. So by performing an AC ripple test, you are verifying that component is functioning properly and not getting AC voltage on a DC system. Thanks!

[@jethro983]

As you note, the rectifier converts the Alternating Current (AC) to Direct Current (DC). If ripple is being measured on the downstream side of the rectifier (say at the battery, and if the rectifier is doing its job, seems that the ripple would be DC. DC rising and falling by a few millivolts. Ripple when seen on an oscilloscope. I am guessing that the term AC ripple test was coined by someone that did not understand rectifiers very well.@@DieselLaptops

[@DieselLaptops]

That is exactly what we are testing. This test helps verify the rectifier bridge DOES NOT have a failure allowing AC voltage to pass through into a DC system(diode failure). A scope or multimeter will show you if you have excessive AC voltage on this system(AC ripple). You will get a very small amount of AC even on a good system just due to the filtering effects of a rectifier, but if it exceeds the spec of half of a volt AC(diode failure), you could have some electrical issues in your system as the control modules work off of DC. Thank you and hope this helps!@@jethro983