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

[@oliverisailovic]

Happy New Year dude!

[@FISHERMAN33RUS]

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]

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]

😮😊 hvala veliki Kralju 👑🥰

[@KD0CAC]

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]

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

[@SeanBZA]

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

[@Luzt.]

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

[@SeanBZA]

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]

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

[@MaxPivovarov]

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

[@joesmith-je3tq]

I am not sure and would need to research it.

[@wktodd]

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

[@tedivester4947]

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

[@joesmith-je3tq]

Poor meters in general.

[@OZ1LQO]

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

[@joesmith-je3tq]

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

[@waynegram8907]

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

[@joesmith-je3tq]

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

[@waynegram8907]

@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?

[@sepertude]

Joe please finnaly test high end Hioki meters

[@joesmith-je3tq]

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.

[@semiRockethr]

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

[@Homer19521]

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]

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.