Don't Stress Your Multi-Meter's MOVs!!!

แชร์
ฝัง
  • เผยแพร่เมื่อ 15 ม.ค. 2025

ความคิดเห็น • 30

  • @oliverisailovic
    @oliverisailovic 15 วันที่ผ่านมา +1

    Happy New Year dude!

    • @joesmith-je3tq
      @joesmith-je3tq  13 วันที่ผ่านมา

      Happy new year to you as well.

  • @UK8CFT
    @UK8CFT 8 วันที่ผ่านมา

    Thank you for your reviews! I bought myself a fluke 17b max as I was very impressed with the test of the f17b+ switch, which withstood 50k rpm and a relatively high transient voltage. Best wishes!!

  • @FISHERMAN33RUS
    @FISHERMAN33RUS 18 วันที่ผ่านมา +5

    Several flukes (which specific model i can't say for shure) was burned by electricians at different places during underground railway voltage measurements, it is nominal DC +825V. Only after they burned few, they realized that commutation process rize this voltage up to 2-3 kV which ordinary multimeter could not withstand.

    • @SeanBZA
      @SeanBZA 18 วันที่ผ่านมา +3

      I saw one where the arctrician tried to measure the primary side of a 11kV transformer. Only parts of the meter that were salvagable were the display, and the 2 fuses. The rest was not, and the PCB was almost totally free of traces from the display down to the jacks, the only copper there being that on solder pads, the rest being a film on the inside of the case.

  • @mp1454
    @mp1454 18 วันที่ผ่านมา +2

    😮😊 hvala veliki Kralju 👑🥰

  • @Luzt.
    @Luzt. 18 วันที่ผ่านมา +2

    Sir, you are creating a new science - meterology. Thank you for educating us, ordinary folks.

  • @wktodd
    @wktodd 18 วันที่ผ่านมา +1

    Mov has an Alien defence mechanism - " you don't dare kill it !"

  • @KD0CAC
    @KD0CAC 18 วันที่ผ่านมา +2

    Joe , you should build a " collector " for the magic smoke - I hear there is a lot of value in the smoke ;)
    Ever since learning about using a " chicken stick " I always thought that a sudden shorting of a capacitor --- might damage a cap ?
    Other channels have been mentioning draining caps with multi meters --- I was suspect of that also .
    Thanks again , been watching for some yrs. now

    • @joesmith-je3tq
      @joesmith-je3tq  18 วันที่ผ่านมา

      It depends on the capacitor. Some are designed for pulse discharge circuits. This is why I am using film capacitors.

    • @SeanBZA
      @SeanBZA 18 วันที่ผ่านมา

      Only unless you can get Lucas branded smoke collection jars, and condense it for long term storage. Otherwise it does not work well.....

  • @MaxPivovarov
    @MaxPivovarov 18 วันที่ผ่านมา +2

    I believe the resistance is caused by arc sputtering of metal onto the surface of the MOV.

    • @joesmith-je3tq
      @joesmith-je3tq  18 วันที่ผ่านมา +1

      I am not sure and would need to research it.

  • @SeanBZA
    @SeanBZA 18 วันที่ผ่านมา +2

    Suprised the MOV's did not go short circuit, though I suspect given more time they would have done so. Had some 1970's era NOS GE MOV's where the one decided that it would go short while in storage, growing a bulge in the one side, though I suspect it was defective from manufacture, as the bulge did not break the coating. Use them a lot as surge arrestors, and when they fail the big ones will trip the breaker, the small ones will simply just detonate into pieces, and have the arc trip the breaker, though it will be open circuit afterwards.

    • @joesmith-je3tq
      @joesmith-je3tq  18 วันที่ผ่านมา +1

      We stopped using them in automotive because of the fire hazard.

  • @tedivester4947
    @tedivester4947 18 วันที่ผ่านมา +1

    It's sad to watch. We need a Society for the preservation and protection of our MOV's. Poor things!

    • @joesmith-je3tq
      @joesmith-je3tq  15 วันที่ผ่านมา

      Poor meters in general.

  • @sepertude
    @sepertude 16 วันที่ผ่านมา

    Joe please finnaly test high end Hioki meters

    • @joesmith-je3tq
      @joesmith-je3tq  15 วันที่ผ่านมา

      I had asked viewers at one time to vote for what they wanted to see. Their was little interest in Hioki. This lack of interest is why I never ran another one.

  • @OZ1LQO
    @OZ1LQO 18 วันที่ผ่านมา

    What is the voltage rating of the Probemaster test leads you're using?

    • @joesmith-je3tq
      @joesmith-je3tq  18 วันที่ผ่านมา +1

      CAT III 1000V, CAT IV 600V, 10A This is the 8000 series I am using.

  • @waynegram8907
    @waynegram8907 16 วันที่ผ่านมา

    What is the "normal" max voltage DVM meters MOV can take? Why don't DVM use NTC MOVs?

    • @joesmith-je3tq
      @joesmith-je3tq  15 วันที่ผ่านมา

      I have never heard of an NTC MOV. Please provide a link for the devices you are referring to.

    • @waynegram8907
      @waynegram8907 15 วันที่ผ่านมา

      @joesmith-je3tq NTC thermistor which is in the family of a MOV, NTC thermistor are used for in-rush current while MOVs are used for voltage spikes and surges. My question is why are MOVs only PTC and not NTC?

    • @joesmith-je3tq
      @joesmith-je3tq  8 วันที่ผ่านมา

      @@waynegram8907 You want to replace the MOVs with an NTC, or the PTCs? Can you explain how that makes any sense to you? Also, I have never heard of an NTC being a family of the MOV. Could you provide any materials where this is mentioned?

  • @Homer19521
    @Homer19521 18 วันที่ผ่านมา +3

    Better to stress the DMM's MOV's than your body due to a high energy EMF. I always assumed that Dave was suggesting this procedure as a way to increase your safety as opposed to always doing it this way. And as you have proven time & time again, most DMM's can be repaired. A dead repair person cannot be. Still, I always appreciate your due diligence and willingness to test to failure, if need be. 👍

    • @joesmith-je3tq
      @joesmith-je3tq  18 วันที่ผ่านมา +1

      Looks like 40 were damaged beyond repair, 15 were damaged and repaired, and 10 survived without damage. As I started looking at higher class meters, chances they could be repaired improved.

  • @Mr.Leeroy
    @Mr.Leeroy 15 วันที่ผ่านมา

    10:41

  • @semiRockethr
    @semiRockethr 18 วันที่ผ่านมา +2

    Hey what is a MOV never seen it my multimeters, must have advanced versions! No MOV no problems! :D