Need help on how to test large inductor

Collapse
X
 
  • Time
  • Show
Clear All
new posts
  • macattack600
    Senior Member
    • Aug 2011
    • 97
    • USA

    #1

    Need help on how to test large inductor

    I am working on a Crest Ultrasonic cleaner , through the inside it leaked liquid on the corner PCB on just one almost C battery sized inductor with steel core. I've replaced diodes and transistors and the board powers the machine correctly but the bad inductor will burn if I run it more than 30 seconds. There are four inductors which feed each to one of the 4 transducers wired in series.

    It seems that the inductor is prob a 20awg with what I would say at least 250+ turns with a metal core. (Looks like a speaker crossover inductor).

    Could I test this to get a close enough value with something like this ?
    https://www.amazon.com/Sinometer-VC6...ords=lcr+meter
    or would I need something else , this meter starts at 2mH I think this would be ok given I unwound the bad inductor and got at least 250turns but the wire broke up and I could'nt properly measure more.

    There is no schematic per pcb part number on the internet there is no
    markings on the inductors . The company that manufactured this has no schematic due to being older model .
    Last edited by macattack600; 11-09-2016, 07:41 PM.
  • Longbow
    Badcaps Veteran
    • Jun 2011
    • 623
    • USA

    #2
    Re: Need help on how to test large inductor

    A few more bits of information could get you going on this project. Photos?
    You can probably find schematics of similar cleaners that will be close enough to yours.
    Are all the inductors driven by the same source, or by different sources? Inductance values on these things will likely be in the multiple Henrys, not critical and rewinding is a good possibility. What kind of transducers are used on this cleaner?

    Check the frequency of operation first - that should be very easy. Remove the faulty inductor and compare the value with another good one. Or: make a guess at the frequency of operation - maybe 50KHz? Using formula for resonance, place a reasonable cap in series with the coil and manually sweep the network using an audio oscillator. (Most go up to 2 MHz) whilst watching for a resonant voltage peak.

    Publish results.
    Is it plugged in?

    Comment

    • stj
      Great Sage 齊天大聖
      • Dec 2009
      • 30931
      • Albion

      #3
      Re: Need help on how to test large inductor

      if it's not open circuit, it does not smell burned, and the core is intact - it's probably fine.

      it's only a coil of wire afterall.

      Comment

      • keeney123
        Lauren
        • Sep 2014
        • 2536
        • United States

        #4
        Re: Need help on how to test large inductor

        Originally posted by macattack600
        I am working on a Crest Ultrasonic cleaner , through the inside it leaked liquid on the corner PCB on just one almost C battery sized inductor with steel core. I've replaced diodes and transistors and the board powers the machine correctly but the bad inductor will burn if I run it more than 30 seconds. There are four inductors which feed each to one of the 4 transducers wired in series.

        It seems that the inductor is prob a 20awg with what I would say at least 250+ turns with a metal core. (Looks like a speaker crossover inductor).

        Could I test this to get a close enough value with something like this ?
        https://www.amazon.com/Sinometer-VC6...ords=lcr+meter
        or would I need something else , this meter starts at 2mH I think this would be ok given I unwound the bad inductor and got at least 250turns but the wire broke up and I could'nt properly measure more.

        There is no schematic per pcb part number on the internet there is no
        markings on the inductors . The company that manufactured this has no schematic due to being older model .
        So what type of transducers is it using? Perhaps some of the coil windings have shorted or are shorting. The insulation could of been compromised if you are using more than water in the cleaner and that got on the coil.
        Last edited by keeney123; 11-17-2016, 04:24 PM.

        Comment

        • Longbow
          Badcaps Veteran
          • Jun 2011
          • 623
          • USA

          #5
          Re: Need help on how to test large inductor

          Originally posted by stj
          if it's not open circuit, it does not smell burned, and the core is intact - it's probably fine. it's only a coil of wire afterall.
          Famous last words.
          Is it plugged in?

          Comment

          • R_J
            Badcaps Legend
            • Jun 2012
            • 9515
            • Canada

            #6
            Re: Need help on how to test large inductor

            Its a good idea to check the transducers, are those the piezo ceramic type? check them for cracks, if they are not cracked they should be ok, many times people drop parts into the tank and that can fracture the transducers.
            Attached Files

            Comment

            • kc8adu
              Super Moderator
              • Nov 2003
              • 8832
              • U.S.A!

              #7
              Re: Need help on how to test large inductor

              since you have already unwound it time to measure the diameter of the wire,get a roll of magnet wire,and start winding.measure the length of the sections as you unwind and break them.within a few feet is good enough.since it is crumbling as you unwind its probably toast pardon the pun.

              Comment

              Related Topics

              Collapse

              • chth96
                How Can I test PWM DM0365R?
                by chth96
                Hello
                I have power adaptor(220V/input, 12V 1.2A/output) which has symptom of fluctuating output DC voltage between 11.5V-12.2V.
                So I opened its plastic case and when switched it on, I heard constant tik tik sound from inside its PCB.
                I measured DC voltage between negative and positive pin of the largest capacitor(400v 10uf) and it was measured contant 300V.
                I also measured ESR value of all capacitors and I noticed that one of capacitor(KMG 16v 470uf), which located in the secondary side, have high ESR value(10 ohm),So I replaced it with same specification NXH capacitor....
                06-18-2025, 04:14 PM
              • momaka
                Corsair CX750M [Model 75-002019] - burned output toroid inductor
                by momaka
                Looks like I may need a little help from the PSU experts (or anyone really! ) I have a Corsair CX750M (Model 75-002019) that I picked up for free about 4 years ago. This is the PSU:



                So here’s what’s strange about this one: it appears to work normally (normal output voltages) and any PC is stable with it. However, after a while (typically 10-20 minutes, but time can vary depending on the load), there is a sweetish smell of burned magnet wire insulation emanating from the PSU. Upon opening the PSU after this happened (many times), I was able to confirm...
                09-19-2021, 08:44 PM
              • khelane
                test active pfc power with lamp test
                by khelane
                Hello
                I have a big problem and that is that in some cases when repairing active pfc power supplies I cannot work with a test lamp. I can only get help with 5 volts standby and for starting and starting I have to work without a lamp and this way there is a possibility of parts exploding and other parts being added.
                Sometimes with a multimeter test the problems can be reduced to some extent, but I had several cases that had to be tested on and online and recently two varistors exploded. They had terrible resistance because the power supplies were over 800 watts.
                Is there a way...
                06-03-2025, 01:00 AM
              • chronic519
                Mats / mods: detected and repaired GPU fault. Cant seem to test after!
                by chronic519
                Hello.

                GPU came in, green lines. Spent lots of time using to get the Mats / mods drive working (found on youtube).
                Found issue with a RAM block
                Replaced, green lines gone.
                Trying to test again, assuming getting the false positive. Originally had over 1K on a single bank. Now getting tosses low between banks.
                Used a good card to test and same results low errors 32+.

                I am just search for some form of command to do a full test on the GPU.
                I just ran the mats command with my good GPU and passed after roughly 40 min.
                The repaired one, ran...
                05-20-2025, 07:56 PM
              • Bartoloni
                Lenovo S145 -15iwl vcore inductor warm.. looking with oscilloscope there is a spike.
                by Bartoloni
                Hi, i have a Lenovo S145 that after 20 seconds shutdown and restart (it's working correctly on thse 20 seconds)
                everything seems ok, but on Vcore inductor ( this is an i3 with just 1 switching power supply for CPU)

                there is an output to teh CPU with a spike.. seems that inductor can't handle the input...
                replaced the capacitor (330) and the inductor (R15) without any change
                any idea? very thank you!

                input of the inductor seems as usual... only strange thing is that the upper/lower voltages seems to be 21V (main power line is 19.3) ... but not sure this...
                12-09-2024, 12:42 PM
              • Loading...
              • No more items.
              Working...