What is a Metal-Oxide Varistor and how it protects a drive | Galco Industrial Electronics

Metal oxide varistors, also known as MOVs are one of the most common types of varistors. They are voltage dependent, nonlinear devices that provide transient suppression. MOVs are composed primarily of zinc oxide with small additions of other metal oxides. The structure of the body consists of a matrix of conductive zinc oxide grains separated by grain boundaries. These boundaries are responsible for blocking conduction at low voltages and are the source of the nonlinear electrical conduction at higher voltages. The use of a metallic oxide within their construction means that MOV’s are extremely effective in absorbing short term voltage transients and have higher energy handling capabilities. As with the normal varistor, the metal oxide varistor starts conduction at a specific voltage and stops conduction when the voltage falls below a threshold voltage.
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With respect to the usage, installation or assembly of any products described in this video, Galco Industrial Electronics, Inc., a Michigan corporation, encourages you to follow the requirements and/or guidelines of: i) the Occupational Safety and Health Act of 1970, Public Law 91-596, as amended, and all laws, rules and regulations implemented in relation thereto; ii) the National Electric Code®; and iii) NFPA 70E®. Any installation, assembly or work described in this video should be performed by a qualified licensed electrician.
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#Galco #MOV #Varistor

[@mongothemaniac5848]

You forgot to mention how Varistors are used to blow a fuse when they fail which is really the purpose of them most of the time. They are put across line in switching power supplies (Live to Neutral) and become a short circuit when rated voltage is exceeded in most cases which results in blowing the mains fuse thus protecting the power supply.

[@electronicsworkshop7131]

kzbin.info/www/bejne/mHnChaiVed58eJY see the detail here

[@baderalqahtani5159]

What if it's a circuit breaker ? It would trip the breaker due to conducting high amps. However, they do it unintentionally, cuz their purpose is to protect the load (PSU) by burning ( becoming like a conventional train 😆)

[@larrybud]

That's a great explanation. I was wondering why resistance would go down when V goes up! Am I right to understand this is needed because a high voltage/low current may not blow the fuse, but would essentially blow the varistor, which then causes a short and a blown fuse. Is that the order of operations?

[@jimmydandy9364]

You should never rely on surge protection in even the good PSUs, they are garbage. Always use a good dedicated surge protector externally, that you plug your computer to. Good surge protectors will have their MOVs fused, so that when the MOV wears out and as it heats up more and more, eventually it will blow the fuse and it will "cut" the surge protection component from the bar, so your surge protector continues to operate as a power bar. That's why you see the "protection" LED go out when you no longer have a functioning MOV, as it heated to a point it blew the fuse inside the bar. The MOV in a PSU, even the best PSUs, do not have an indicator light telling you that surge protection is live. so this gives potential for the MOV to melt, go up in flames and cause a fire, the same as with old cheaper surge protectors that did not have a fuse. I've had an old surge bar go in a ball of fire when the MOVs were cooked and finished. All the surge protectors I use now are fused, when the MOV is cooked and finished, the contact is broken (fuse goes off) and the power bar can continue, without the risk of a fire, but with no protection. Your 15A breaker will not trip unless the wire gets hot enough so that the end that is plugged to the breaker side is hot enough to trip the switch - this is why it is very important for MOVs to be fused. I was very disappointed to see that in computer PSUs it isn't the case, no wonder you see stories of people's PSU going up in smoke / fire. which is why I never rely on a PSUs surge protection, EVER, I always use an external quality surge protector that will take the hit first, before the PSU. Surge protection in PSUs is weak, it's nowhere even close as good surge protection bars. The bars I use have a total protection of 4000 joules, fused. A MOV can be your best friend and your worst enemy too. My very old surge protection that threw a large ball of fire and sparks at me is a lesson well learned, lucky for me that fire did not touch something and no fire occurred, but inside a PSU with all the components in there, if that were to happen it would be a whole different story - it would be a fireworks show ! Don't be fooled by all the good reviews of PSUs online, a lot of companies now are finding clever ways to cheap out and cut corner - they may still use quality components in their high end products, but will most certainly always cheap out somewhere - I've seen myself some good PSUs with good components but some bad implementations, that, in the right conditions, could be fire hazards. MOVs wear out with time, and the surge it protects against is cumulative, each time it deals with one, it becomes weaker and protects less, and heats MORE, without an indicator light, there is no way for you to know the surge protection status of your PSU, that in itself is VERY BAD !!!!

[@BarefootBeekeeper]

Her voice could slice concrete.

[@highwaystar4518]

lmao

[@racenuke]

Finally an American explaining electronic equipment. Thank you!

[@ryantoomey611]

The magic smoke makes the MOV work. Once the magic smoke is let out the MOV no longer works.

[@samjohn1754]

sounds legit ... totally

[@victorjbarker]

Wow never heard that in electronics before... smh

[@murrfeeling]

Who are you, who are so wise in the ways of science?

[@jamesharris5198]

Thanks, this actually happened on a project and now we can monitor for the source of the surge and remediate it.

[@Daa253]

A guy who owns a small rental shop in my town gave me a power gate control board and he said the varistors kept blowing up. I'm fixing it for him! $200 board!

[@stizandelasage]

now I know how to use it thank you this component is not in my book

[@AlloyedFrequencies]

Thank you so much for explaining

[@remyarcala6182]

Great information thanks!

[@indigoskywalker]

its like listening to an american reporter on us news lol

[@n8loux]

i was thinking the same. almost had to find a different video, but i powered through because the information was good otherwise lol

[@eis27182818]

@@n8loux Haha holy crap yes, the cadence and pronunciation and everything.

[@victorjbarker]

Don't forget all the mannerisms, facial expressions and nods...

[@ZMKmagic]

that may be the case because she's reading off the wikipedia article for varistors xP

[@Mr.Leeroy]

I was reading out loud in the same manner back in school when I had zero understanding what am I pronoucing, lol

[@tehniathali2285]

I am college student (Commerce) and had experienced burning of new Dell Laptop Charger-Adapter. I can't carry the heavy UPS with Laptop! Here are my queries:- - Q1) Is Spike Buster also called Surge Protector? If not, can't we have both in one Plug? - Q2) For protecting Laptops, the maximum AC Voltage is 240V because the Charger-Adapters are rated from AC 110-240V. So which MOV should I buy for protecting the Charger-Adapter? - Q3) I am confused! Should I consider 220V or 230V or 240V for the safety of the Adapter? Accordingly, what would be the MOV designation? - Q4) Alternatively, why not use step-down transformer to limit the AC Voltage to 150 or 200? Because one has to replace the burnt-out MOV in your idea! - Q5) Next Alternative is to make auto-Spike Buster with setting of 200 V AC! In the market, this is available for R1400/-. But it is set at 240 V. It auto-disconnects at a 240 V and auto-reconnects after the voltage reduces without the effort of replacing the burnt-out MOV? Can we make it at home with the max Voltage set at 200V? --

[@agstechnicalsupport]

Good summary for Metal Oxide Varistors, thank you !

[@GalcoIndustrial]

Welcome, glad you liked it

[@kaletsugas]

How do you choose a MOV value for your needs? Ex. I'd like to add it in my diy SMPS.

[@Leafy597]

The turbo-encabulator has now reached a high level of development, it’s being successfully used in the operation of novertrunnions.

[@michaelbeckerman7532]

I was thinking the exact same thing! She really should make a turbo-encabulator video herself as she has the PERFECT voice and presentation style for it. Too good!

[@Leafy597]

@@michaelbeckerman7532 Yes!

[@jenickjohnson4361]

I got a varistor coded 10s471k burnt and I want to change it so i bought a varistor which the shop keeper say it varies from 471k to 1000k. can i use it?

[@rupeshshukla1388]

Ofcourse...

[@mrmaherani7077]

How beautiful her voice is.

[@TonyHenrique]

Nice video

[@GalcoIndustrial]

Thank you

[@aungkyawsoe6897]

Thank you!

[@maxwang2537]

Good video, thanks. One question-once a mov is blown up, does it remain shorted or open, usually? Probably no, I’m thinking if a fuse in combination would protect the system after the mov’s blowing up. This is possible only if the mov could short the fuse (then blows it up) when it’s sacrificing itself).

[@shelbysgarage5828]

The mov is actually meant to blow the fuse, so (closed)?

[@rupeshshukla1388]

It behive a short & fuse will open & protect our supply or circuit..

[@levyphiri5275]

@@shelbysgarage5828 ur the man, was also wondering if if it remains closed or open because my power supply keeps blowing the fuse when i replace it, learnt something from you.

[@shelbysgarage5828]

@@levyphiri5275 hey so it could technically blow either way. And just by not allowing the proper voltages threw things won't work. Or work properly. The fact that your fuse keeps blowing to me suggest something else down stream is your issue. Let's just say your board is trash if you can't fix it.... So put a solid jumper across the blwon fuse and try to find where the power goes before it blows lol

[@shelbysgarage5828]

@@levyphiri5275 don't put full power onto your board just enough to see where power gets stopped. Odds have it that will be where you find your issue

[@electrosound4595]

i want help... i have 500 watt load and want to protect by surge voltage. which MOV or any circuit protect my load by burning. pls help.

[@florind.5711]

20n431k for 230V AC fuse 3.15A slow blow= trage= T3.15

[@philippinetech1699]

How to check a good varistor using multimeter

[@GauravGupta-pb8mk]

Thank you

[@rotcataergeht]

I took keurig k500 coffee machine to Thailand n plugin in, forgetting its 220v over here. I Hope i didn't break its motor.

[@shawn576]

I'm so high that I thought the video was going to introduce Katie as the name of the varistor in some animated thing.

[@CHzwaves]

Thanks Buddy 😎

[@kalimuthukalimuthu3814]

10d201 panasonic variester equalent parts

[@benjaminbadrakh1644]

Hey that fluke meter there has a few MOVs in it.

[@MrGoodKingBad]

thanx K.T,

[@wcnur]

Uff it's hard to stay focused with varistor :D

[@componentexplosion]

wow super burning 3:00

[@snkrinnovation9791]

Does it divert current to ground or the excess energy goes out by thermal radiation?

[@GalcoIndustrial]

An MOV just conducts between its 2 terminals. So if 1 end was connected to ground then it would conduct to ground. Think of this device as a kind of automatic variable resistor that can go from MEGG ohms to zero at a specific voltage. Or simular to back to back zener diode with a really high zener voltage, 200 to 1000 volt range. MOV's conduct very hard once they avalanche into conduction. This is why they also have a Joule rating. Joules are the amount of energy the MOV can tolerate before failure.

[@sudhirpatil3434]

nice= very nice information

[@TechReveals]

loved it

[@michelberard7496]

Where can I buy some of these to protect my small solar panel system?

[@shelbysgarage5828]

EBay sells them

[@pjeaton58]

What about TRANZORB diodes ??

[@brennanac1]

How do you know the size I have one that burned out that is green it is on a AC ice machine the numbers are burned off thank you

[@GalcoIndustrial]

First thing you have to know is the line voltage the machine runs on and were these devices across that line or the motor terminals? The next thing we need to know is the physical size of it, is there anything left to look at?

[@brennanac1]

Thank you for getting back with me it's a hundred twenty volt AC I have to measure it thanks again

[@hellhound-si5oz]

How to accidentally did that with a generator but the generator 208 and fed it to a 120-volt power strip by accident didn't realize it had a surge protector in it it released the smoke

[@KameswarKolluri]

suppose we remove the varistor temporarily will the circuit work as before?

[@Agent24Electronics]

Yes but it will have no protection, so only do so for testing.

[@danishimran3462]

Working but at risk

[@samjohn1754]

You can literally see the 'MOV Expert's' eyes move.. reading from the teleprompter 🤣🤣

[@steamcastle]

most people who are prepared write script helps them not make mistakes.

[@ShrirajHegde]

Reading teleprompter isn't a shameful thing, it's being well-prepared

[@victorjbarker]

Experts and Engineers can read monitors aa well... Don't be so narrow minded...

[@EnsignJC]

I don't get it. When the voltage is below the breakdown voltage, the varistor doesn't conduct. And when the voltage is over the breakdown voltage, the varistor burns, creating an open circuit, which doesn't conduct. Why not just have an open circuit in the first place since it doesn't conduct, why have the varistor that never conducts?

[@WUHAHAYOUSUCK]

it's meant to protect a transient high voltage, in another word, a voltage spike, in most cases the high voltage will be too short to cause any burn on the MOV, it will just dissipate as heat. in the video it only burnt because it was a long lasting high voltage.

[@dandoyle9881]

When the voltage exceeds a certain amount the varistor conducts, thus reducing the voltage. It only burns when the total watts conducted exceeds the rated wattage of the varistor. Once it burns, that ends the regulating function. Now you need a new one.

[@rezarthabili3353]

Can varistors be called ceramic capacitors? (or thats what they are ), I'm not very accustomed with electronics but i like them.

[@GalcoIndustrial]

No they are not capacitors. However they do look like ceramic disc type capacitors don't they. Varistors are a type of voltage spike clipping device. A capacitor is simply an AC voltage reactive device. I might suggest you look them up in a book from your local library, eh.

[@rezarthabili3353]

@@GalcoIndustrial Thank you, yeah i definitely need to gather more information.

[@danishimran3462]

Not a ceramic capesiter.ceramic capesiter has value written on it .

[@Electricalsupervisor]

is there other shapes than the disc shape?

[@GalcoIndustrial]

Yes they come in many sizes and a few different package styles.

[@GalcoIndustrial]

Here we showed the Radial lead type, they also come in Axial lead, panel mount and surface mount type packages. Then they have a "Joules" rating, this is how much energy they can quench/absorb without self distructing. They act as an electrical spike clipper, as soon as a voltage spikes up to the MOV conduction value it instantly turns on and effectively shorts out to clip that spike to the MOV rated conduction value. COOL?

[@zjvuiunkgzkgvb]

very nice video with definitions copied from wikipedia :D

[@Jimmeh_B]

electronics with fran !

[@mathaithomas3642]

I have a question: is it necessary to have a good earthing for MOV to function properly?

[@GalcoIndustrial]

It is always a good idea to have good earth ground connections for safety. However it will not necessarily make an MOV function differently. All an MOV can do is to react to the difference in potential across its leads. If 1 side is connected to ground and that causes more or less voltage across its leads then it may react differently than if it was not. Remember an MOV simply clips voltage spikes to keep the potential/voltage clamped to some maximum level depending on the rating of the MOV you are using.

[@joeshmoe5935]

Do varistors have a specific direction for current flow? I.E. input leg and out put leg. I am working with VAC here. I don't need no comments about " If you have to ask......"

[@MrSleepProductionsInc]

No polarity, put them in any which way.

[@joeshmoe5935]

@@MrSleepProductionsInc thanks for be so straight forward and honest/direct.

[@johnmp1470]

if you have to ask you really shouldn't be working with vac.

[@mambrake]

Why put such a beautiful creature of God to explain. All I could do is look into her hypnotizing eyes.

[@dutcher517]

You are a fucking creep.

[@xntumrfo9ivrnwf]

Agree - and lol at the soyboy below calling you a creep.

[@poymenov]

Gj

[@DupczacyBawol]

current flow in only 1 direction, huh? LOL.

[@ryantoomey611]

It acts like a diode. Listen at 1:17

[@rich1051414]

​@@ryantoomey611 Or like a zener, since it's reverse voltage characteristics is what is usually exploited to suppress high voltage transience. It does seem odd to me to word it like that though. Seems like 'current flows in no direction(speaking in ideals here)... unless it's voltage is too high' is more accurate to me.

[@superpooper_2030]

Indiot, is mov connected only via live or neutral line?

[@brocksamson8634]

Yo Katie can I take you out to dinner?

[@TonyoTorres]

I just felt in love :-) her smile, the cute way her nose pull oxygen aaaaaaaahhh :-) etc

[@slybunda]

whats more impressive is how she is talking though her nose

[@mohammedyusuff8081]

😅😅

[@funsubrehman668]

you are brilliant sweet girl

[@0dium.]

yeah , she reads the teleprompter quite gracefully ...

[@xntumrfo9ivrnwf]

@@0dium. Yeah, I think the chances of her being an "MOV expert" are about as high as her voice.

[@dinhscot]

Smart Chick is hot, I think I'm in love

[@mrfrog8502]

What a load of bull.... 1:10 MOV doesn't have diode junction inside and it doesn't conduct in only one way. Maybe somebody should fact check not just publish a pretty video with an actor 'MOV expert' reading of the teleprompter and wearing a lab coat.

[@mahela1993]

Seems like more of a infomercial than a tutorial. KZbin DIYers explain things better.