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Re: AC Voltage
Here part cost $0.15 each? Shipping? is around $6.00 so buy more than one for next time. The good news about part is only voltage you look at for most electronics.??
If you use whole like use for solar systems that is real big one with price to match.? https://www.jameco.com/z/V130LA5-James-Electronics-Varistor-205V-2500A-Surge-Through-Hole-10mm-Disc_667041.html?CID=MERCH |
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Re: AC Voltage
The Varistor use today every where today beyond the mini lathes and DRO'S.? They are not plug in like fuse.?
It is found on the other side of fuse or breaker. You have disconnecte to test the part.? If still good the VOM will read very high ohms.? If bad zero ohms.? It is only a safety part and does nothing till you have voltage spike.? Some will just cut the part out remember if do this you power strip with a Varistor built in.? If you do welding you can trip this Varistor.? |
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Re: AC Voltage
¿ªÔÆÌåÓý
AC is an important subject, and I thank for all input.
Please keep on teaching us:?
Most of us know that the Earth cable (GND)? is important.
However, many (include me) dont have it in the workshop. (it will be fixed soon)
What is the main function of this cable that we connect to a cupper pipe (not steel) or into a cupper plate in the garden?
Is it that wild electricity shall blows the Fuse before it blows me?
Make a better stable AC ?
To be a reference point for what MOV etc. is doing ?
/johannes
From: [email protected] <[email protected]> on behalf of BuffaloJohn <johndurbetaki@...>
Sent: Saturday, May 18, 2024 9:27 AM To: [email protected] <[email protected]> Subject: Re: [7x12MiniLathe] AC Voltage ?
Buried power distribution helps to reduce the chance that a lightning strike will travel into the building. However, not all power distribution is buried, it is above ground some distance away from where it goes underground and
that is where transient can be injected. To protect against this, the power company has lightning arrestors that they install to protect their equipment (transformers, etc.). This reduces the transient that enter a building, but does not eliminate them.
As for the 40 year old TVS, you think
it is still good, but how do you really know? Have you examined the MOVs? We have seen open circuit MOVs as failures and as such, the light that says it is still working gives a false indication. If you look at the circuit of a three pin MOV, you can see how
failure as an open will allow the third leg to let the indicator still light. The specs you list are the TVS specs, not the specs of the devices plugged into the building power distribution circuit.
On Sat, May 18, 2024 at 7:40?AM Pierre-Raymond Rondelle via
<pierreraymondrondelle=[email protected]> wrote:
-- Buffalo John |
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Re: AC Voltage
Buried power distribution helps to reduce the chance that a lightning strike will travel into the building. However, not all power distribution is buried, it is above ground some distance away from where it goes underground and that is where transient can be injected. To protect against this, the power company has lightning arrestors that they install to protect their equipment (transformers, etc.). This reduces the transient that enter a building, but does not eliminate them. As for the 40 year old TVS, you think it is still good, but how do you really know? Have you examined the MOVs? We have seen open circuit MOVs as failures and as such, the light that says it is still working gives a false indication. If you look at the circuit of a three pin MOV, you can see how failure as an open will allow the third leg to let the indicator still light. The specs you list are the TVS specs, not the specs of the devices plugged into the building power distribution circuit. On Sat, May 18, 2024 at 7:40?AM Pierre-Raymond Rondelle via <pierreraymondrondelle=[email protected]> wrote:
--
Buffalo John |
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Re: AC Voltage
¿ªÔÆÌåÓý1- MOV failure mode is short circuit, not open circuit. Never put such a device on the fridge or a freezer line ! 2- Use exclusively MOVs on AC lines Of course, the earthing circuit is of a prime importance: the the surge path must have a very low stray inductance and its resistance be compliant to the standards. As a matter of example: At home, located in a quite high keraunic area, all the grid distribution cables are buried and it's a favorable situation. I have a 40y-old 220Vac protection still alive, with 3 varistors (phase-neutral, phase-earth and neutral-hearth) 400V clamping voltage @ 1mA, with a limitation of 700V for a 10Amp shock, 1200V for a 2500A shock, 1400V for 5kA or 1500V for 10kA. Response time is better than 50ns. The device has it's own earth 1m below with a straight cable, the protection is placed at the head of the distribution cabinet located 5m after the company's counter. my earth ground network resistance is well below 50 Ohms when the soil is dry. Since it's been installed, the standard voltage has been establish to 230V and I didn't see any difference. I never had any issue for 40 years. It's not the same in my neighborhood !! Then at the computer level, just because I'm paranoiac (!), i have the same scheme but with 275 V service varistors I replaced the original 250Vac by Chinese components because they were too close to the peak value of the grid voltage. The earth path is shorter than 1 meter. Read this: and for those who can read French Language. This book is very rich hence highly recommended, written both in worker language ans engineer's one ; worth to be translated with Googletrans. On 17.05.24 23:43, BuffaloJohn via
groups.io wrote:
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Re: AC Voltage
¿ªÔÆÌåÓýwe had them across the line outputs I believe on all of our computer filters . Power cord , breaker, filter MOV or maybe it was on the filter inputs . that was 30 something years back . animal On 5/17/24 9:23 PM, davesmith1800
wrote:
On Fri, May 17, 2024 at 07:32 PM, mike allen wrote: |
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Re: AC Voltage
Metal-Oxide Varistor or (MOV). ?This typical found on board of motor controller of your mini lathe or other electronics like DRO'S?
Even TVS?
?
DaveOn Fri, May 17, 2024 at 07:32 PM, mike allen wrote:
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Re: AC Voltage
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Not the electronic thyristor? |
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Re: AC Voltage
¿ªÔÆÌåÓýthat bag of 100 probably came over a ocean to get to ya . Shit that I need to be able to count on I prefer that it ca,e from the island of USA . I don't think that ya can honestly test a system which ya replaced a thyristor without a Hi-pot machine ? Or maybe ya can .? ??? That pumped storage hydro sounds like a pretty darn? good setup ! Thanks for the link . ??? animal On 5/17/24 2:01 PM, davesmith1800
wrote:
I look it up just like a power strip. One time use like a fuse.? |
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Re: AC Voltage
¿ªÔÆÌåÓýReminds me of a great Casey Stengel-ism ¡°No one goes there any more, it¡¯s too crowded¡±I was actually just reading an Washington Post article about how the California grid operators have the problem that they¡¯re getting too much power back from all the household solar that¡¯s installed. Free gift link?? There¡¯s a bunch of different technologies coming online to capture and store that excess energy, but they haven¡¯t caught up yet. Stuff like Iron-Air batteries??, and pumped storage hydro? Those iron air batteries are described as ¡¯the size of a washer-dryer ¡® combo; I wonder how much power they hold? That¡¯s a size that could conceivably work, space-wise to take a home off the grid, coupled with panels on the roof. ?
--?
Bruce Johnson The less a man knows about how sausages and laws are made, the easier it is to steal his vote and give him botulism. |
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Re: AC Voltage
Chris Albertson
¿ªÔÆÌåÓý
?Ther are no new homes for under $1M, and very hard to find for under $1.5M. ?But still they sell very fast as there are an unlimited number of buyers who can afford it or more. ?Near me by the beach, 3X to 5X higher. ?? Then that $10K upfront investment saves you $100 per month on the electric bill, that is a fast payback and then for the next 15 years you make $100/month profit. ? Most people will opt for a larger system and spend closer to 20K so most of their electric bill is covered. About what is covered? ?A surge protector is wired in PARALLEL to all house wires. ?It is not wired in series. ? So YES, it DOES protect against internally generated surges. ?In fact, placing a 200A protection in your panel box would offer some protection to neighbors who share the same utility pole transformer. ?(limited by resistance in the wires). The device clamps the rails in the box to some maximum voltage. ?It would 100% certain stop the surge from jumping across branch circuits
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Re: AC Voltage
Yes, like I wrote earlier, that is a MOV - Metal Oxide Varistor and they have either two or three leads. The ones with three leads can be used to indicate when the MOV has blown. The ones with two leads are a crapshoot if they are still good, depends how they failed. Most surge suppressors use MOVs. The biggest problem with MOVs is that the clamping voltage is really high. A MOV with an AC working voltage of 130VAC has a clamping voltage of over 350V, so you can still blow the electronics out. On Fri, May 17, 2024 at 2:21?PM davesmith1800 via <davesmith1=[email protected]> wrote: Found the name varistor. --
Buffalo John |
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Re: AC Voltage
Found the name varistor.
I was little I hope mini lathe has one or just power strip in is easier to replace. A varistor (a.k.a. voltage-dependent resistor (VDR)) is a surge protecting electronic component with an electrical resistance that varies with the applied voltage.[2] It has a nonlinear, non-ohmic current¨Cvoltage characteristic that is similar to that of a diode. Unlike a diode however, it has the same characteristic for both directions of traversing current. Traditionally, varistors were indeed constructed by connecting two rectifiers, such as the copper-oxide or germanium-oxide rectifier in antiparallel configuration. At low voltage the varistor has a high electrical resistance which decreases as the voltage is raised. Modern varistors are primarily based on sintered ceramic metal-oxide materials which exhibit directional behavior only on a microscopic scale. This type is commonly known as the metal-oxide varistor (MOV). ?
?
Metal-oxide varistor manufactured by Siemens & Halske AG. |
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Re: AC Voltage
Looks like plugs in every time to place it by a electrician.?
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20 years ago that cost $160.00 and hard wire.? At less price is coming down.? More pain? It does not protect against welders only what come from power pole.? I will stick power strip for my mini lathe.? The new home cost of solar adds $10,000 per news Dave? On Fri, May 17, 2024 at 11:41 AM, Chris Albertson wrote:
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Re: AC Voltage
That Square D unit is a MOV device and whether it is single use or so is dependant on the surge it handled. There is a lamp on the from which will indicate it must be replaced as the MOVs are shot. I spent a lot of time working on surge protection in a prior life and _all_ MOV (Metal Oxide Varistor) devices will have a lifetime based on the number of surges it has handled. The more and the higher the surges, the shorter the life. We ended up using a different device: They are not cheap, but we were installing them in places where we had lots of lightning and we had cameras up on metal poles. Just the voltage gradient of the storm cloud was enough to blow up equipment and a strike was enhanced because we had metal poles 30ft into the air. MOV suppressors lasted only partially through a storm and then you had to buy a new one and sometimes replace the gear on the pole. The Brick Wall units lasted for years and we didn't ever have a failure from them. HOWEVER, it you want to protect your lathe or mill or any other shop equipment, a power strip with MOVs will usually and reliably do the job. And, I like that it has a dedicated switch which makes me have an extra step to make sure I have started up safely. On Fri, May 17, 2024 at 11:41?AM Chris Albertson via <albertson.chris=[email protected]> wrote:
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animal
On 5/16/24 9:41 PM, Chris Albertson wrote:
The ¡°best¡±?? The latest electric code (here in the US, the NEC) has taken all the fun out of this.? All new service entrance panels are required to have ¡°Whole House¡± surge protection.? This only applies to newly installed panels in new construction or retrofit.? But if you are going to worry about protecting stuff, you might as well just do it once
These devices are easy to install into an old panel and because they are required, they are available ¡°everywhere¡±. ? ?Just put one of these in and be done with it and it will cover your TV, computer, power tools, car charger, and whatever.
There are two basic kinds, one snaps in like a larger size 220 volt circuit breaker and the other screws into a knockout.
OK, but you really wanted a AC-DC-AC system.? You might be in luck because that is how all brushless motors work. ? There is one of those inside the lathe already if you have a brushless motor
But if I am not mistaken, I think all mini lathes use PWM to control the motor.? If so, then you already have a kind of AC-DC-AC system in from of the lathe's motor.
On May 16, 2024, at 8:19?PM, Johannes via <johannes@...> wrote:
What is the best AC protector/stabilator for a 7x14 lathe?There are many types: one for your computer, one for your fridge.Full AC-DC-AC is maybe a littlebit luxury?
/johannes