Advice on a DVA Peak Voltage Meter

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  • seakaye12
    seakaye12
    US Member - 2 Years
    Replies: 395
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    #182997

    I am looking for advice in preparation to purchase of a good DVA (Peak Voltage) meter….so I am able to properly test stators and switchboxes and the like. I currently have a Harbor Freight P98674 DVM. Perhaps I can add a DVA adapter to this or maybe I need to get a different meter with the feature built in. I would appreciate knowing what you use….and/or what you would recommend.

    Thanks, Chuck

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    frankr
    frankr
    US Member - 1 Year
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    #183003

    Being old school, I never owned one back in the days when I was twirling wrenches for a living—-nor did any one else. But in more modern days things are better now. Anyhoo, I still don’t own a “real” one, but I did cobble up an adapter. The actual parts cost less than a buck, plus however fancy you want to get as far as a case, test leads, etc. The circuit floats all over the Internet. Here is one version. I will say that people go nuts over the capacitor, tending to use one that is way too big. The one I used is only 0.2 ufd and it works for me.

    • This reply was modified 1 week, 2 days ago by Mumbles Mumbles.
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    Mumbles
    Mumbles
    Canada Member - 2 Years
    Replies: 4185
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    #183043

    I recently purchased this DVA adapter to use with one of my multimeters and I believe it max’s out at 400 volts which is enough for any CD ignition components I ever work on. I still haven’t used it so I can’t really say much about it except it was a cheaper way to go instead of buying a peak reading voltmeter.

    https://www.amazon.ca/gp/product/B0093U3TFG/ref=ppx_yo_dt_b_asin_title_o05_s00?ie=UTF8&psc=1

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    frankr
    frankr
    US Member - 1 Year
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    #183045

    My only question is since it plugs into the “COM” and “DCV” jacks on your multimeter, is there a standard spacing between the jacks?

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    crosbyman
    Canada Member - 1 Year
    Replies: 1228
    Topics: 161
    #183049

    just a question …

    if PEAK Voltage is = AC + xx % can’t we just assume that any AC reading + xx% is good enough to estimate the peak value ?

    frankr
    frankr
    US Member - 1 Year
    Replies: 4390
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    #183053

    One would think so, but it isn’t that simple. Depending on what you are testing, it may not be an AC sine wave (trigger sensors). Or you may be testing DC pulses (power pack output) etc, etc, etc

    labrador-guy
    labrador-guy
    US Member - 2 Years
    Replies: 206
    Topics: 28
    #183058

    I am also old school too! I don’t understand why you are looking at peek voltage. On small engines the faster it spins the higher the voltage. At one time high speed motors with lights would spin so fast that all lights hooked to it would burn out. Modern regulators cured that.
    So keep your peek voltage high enough to make spark, that should work!

    dale

    seakaye12
    seakaye12
    US Member - 2 Years
    Replies: 395
    Topics: 104
    #183064

    Being old school, I never owned one back in the days when I was twirling wrenches for a living—-nor did any one else. But in more modern days things are better now. Anyhoo, I still don’t own a “real” one, but I did cobble up an adapter. The actual parts cost less than a buck, plus however fancy you want to get as far as a case, test leads, etc. The circuit floats all over the Internet. Here is one version. I will say that people go nuts over the capacitor, tending to use one that is way too big. The one I used is only 0.2 ufd and it works for me.

    Frank I made one too; I even think it works but I don’t really have all that much confidence in it so I thought it might be time to buy a commercially made one that people can vouch for.
    And; yes….I hope the spacing is standard. I doubt it is though….one of the vendors for these seems to offer a special version for Fluke meters….and I bet that is because the spacing on theirs is different from what else is commonly used. They probably do that on purpose LOL…..
    Chuck

    • This reply was modified 1 week, 2 days ago by seakaye12 seakaye12.
    seakaye12
    seakaye12
    US Member - 2 Years
    Replies: 395
    Topics: 104
    #183065

    I am also old school too! I don’t understand why you are looking at peek voltage. On small engines the faster it spins the higher the voltage. At one time high speed motors with lights would spin so fast that all lights hooked to it would burn out. Modern regulators cured that.

    So keep your peek voltage high enough to make spark, that should work!dale

    Dale I think you are essentially correct but it is a diagnostic thing. If you don’t have spark you need to track back through the maze of $350.00 switchboxes and triggers and stators in an effort to identify positively which part is causing the problem. Otherwise you end up throwing expensive parts at it
    Chuck

    Mumbles
    Mumbles
    Canada Member - 2 Years
    Replies: 4185
    Topics: 424
    #183066

    The Direct Voltage Adapter is used in conjunction with a multimeter for testing CD (Capacitor Discharge) ignition components, not points style magnetos as found in older motors. Specific values for stator and charge coil output are given in shop manuals along with values for testing ignition and trigger coils etc at both static and cranking/idling speeds. Testing CD ignition components individually helps to narrow down which component is at fault and eliminates the guesswork. I can already see the DVA coming in handy on the Merc/Mariner CD ignitions with the troublesome switch boxes.

    seakaye12
    seakaye12
    US Member - 2 Years
    Replies: 395
    Topics: 104
    #183068

    Here’s another one I stumbled on last night. These people sell ignition components for motorcycles…..and they sell a meter/DVA Adapter for $58.00. Anyone here familiar with them?

    https://www.rmstator.com/en_ww/products/kit-digital-multimeter-voltage-peak-reading-dva-adapter-rm22980

    One thing I notice with these “cheap” adapters….is that the meter does not “remember” the peak reading. You have to be looking at the meter during cranking and observe the highest value….because it immediately begins to drop when cranking ends and the capacitor inside the adapter begins its discharge. I wonder if the “real” DVA meters like a Fluke with the MIN/MAX switch is different in that respect? Maybe it holds the high reading for viewing “after the event?

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    outbdnut2
    US Member - 2 Years
    Replies: 1139
    Topics: 57
    #183071

    If the input impedance of the voltmeter you use is too low, it will drain off the capacitor before the digital display can settle out with a reading. I have a cheapie peak reading adapter that I bought, and a high impedance meter, but the peak reading still goes away pretty fast. Ideally, you need a peak reading circuit coupled to a sample and hold circuit; or , better yet, a storage oscilloscope which can grab as little as one pulse and keep it on the screen, allowing you to see both the peak voltage and the waveform shape. Storage scopes are not cheap, starting at around $250.00. I just did an online search and came up with this adapter which converts your laptop or other PC to a storage oscilloscope for $58.00 – I’m thinking about buying one, but then, being a retired electrical engineer, I have other uses for it as well.
    Dave
    https://www.amazon.com/Hantek-HT6022BE20Mhz-Digital-Oscilloscope-Bandwidth/dp/B009H4AYII/ref=sr_1_14?crid=HSPPVCN180TF&keywords=storage+oscilloscope&qid=1568215262&s=gateway&sprefix=%22storage+oscilloscope%2Caps%2C217&sr=8-14

    frankr
    frankr
    US Member - 1 Year
    Replies: 4390
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    #183076

    delete

    • This reply was modified 1 week, 2 days ago by frankr frankr.
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