Temperature stratification, similar to
Oil & Vinegar salad dressing, as seen in a glass bottle.
The ceiling fan simply "Shakes the
Bottle", and keeps shaking all day while it is on.
On 5/20/2024 11:28 AM, davesmith1800
wrote:
toggle quoted message
Show quoted text
Trying this on hot summer day?
Before turning on your ceiling fan and? using your mini lathe.?
Check your cell temperature and room temperature at the mini lathe
even try floor.??
Big surprise?
Dave?
|
On 5/20/2024 11:28 AM, davesmith1800
wrote:
toggle quoted message
Show quoted text
Trying this on hot summer day?
Before turning on your ceiling fan and? using your mini lathe.?
Check your cell temperature and room temperature at the mini lathe
even try floor.??
Big surprise?
Dave?
|
Trying this on hot summer day?
Before turning on your ceiling fan and? using your mini lathe.? Check your cell temperature and room temperature at the mini lathe even try floor.??
Big surprise?
Dave?
|
The varistor is good to know about it some many things today?
It dates back to 1927 but did see any electronics till 1970's now it almost everything including the mini lathe controller boad.
.
Dave?
toggle quoted message
Show quoted text
On Sun, May 19, 2024 at 11:50 AM, Johannes wrote:
Thanks Buffalo John
for your good lesson, I learned news and refresh old knowledge that was lost.
?
With few words: Ground cable is important, and it have to be good.
/johannes
?
?
?
?
See my answers below in red:
?
When in doubt, keep it simple, make sure your protection devices have all the proper connections to work, make sure your building wiring is strong enough to support your application (wiring size, breaker type and size, panel wiring, panel balance, etc. etc. etc.), and when in doubt - ask.
On Sat, May 18, 2024 at 9:56?AM Johannes wrote:
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)
Yes, getting a working ground is an important thing to fix.
?
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?
Attaching to interior piping of a building was used in the past because that copper pipe ran outside into the actual ground. However, it is not a good way to make a ground connection because there are many ways it can be ineffective or dangerous.And - you might not have a copper pipe going outside anymore. My son had his house repiped and the copper going outside was replaced with PEX.
?
What you need is to have the ground circuit actually connected to an EARTH return - which means a "ground" rod driven into the ground, near the electrical panel, with a heavy gauge wire connecting the rod to the panel. Grounds within the building also need to be wired and not assumed to be connected by conduit.
Is it that wild electricity shall blows the Fuse before it blows me?
Wild electricity is an interesting way to look at it!?
?
The purpose of the ground in these machine tools applications is to divert a live circuit to a safer place - ground. For example, suppose your motor overheats and the insulation is damaged. It is possible that the damaged insulation lets the live power to the motor flow to the case of the motor. If someone were to touch the live circuit by touching the motor housing or something that is bolted to the motor and then also touch something that has a actual ground connection, it is possible for current to flow between one touch to the other. If it is mains power, it can be lots of voltage and lots of current. While the fuse might blow when you become the bridge between hot and ground, more likely is that you would get a shock and worse - and the fuse wouldn't blow.
?
A GFCI (Ground Fault Circuit Interrupter) breaker would have a better chance of stopping you from becoming the fusible link than a fuse.
?
An AFCI (Arc Fault Circuit Interrupter) breaker will also be useful when dealing with leakages as it can detect leakage from more than just ground.
Make a better stable AC ?
Grounds don't make the AC more stable, they just make a return path for errant current. The quality of the AC coming in is governed by the power transformer that connects to the power company, the wiring along the way, balancing of the loads, etc. While phases are referenced to ground, locally it might be different and this topic is a bit more than I want to tackle here.?
?
We had a case where a link in a meter corroded (really old meter, really old house (knob and tube in places still live), and something took out the circuit in such a way that the 240 coming in to the old house didn't have a neutral reference that was solid One side had 40v and the other 200v. That was a power company call but a bunch of equipment was destroyed by the overvoltage situation (including a couple of MOV surge protectors).
To be a reference point for what MOV etc. is doing ?
Many MOV circuits are using the ground as the place to dump the transients. In practice, this can have unintended consequences if the ground return isn't really good. Power strips with cords and MOVs work only if the ground in the building wiring is solid and not tied to neutral anywhere but where it is supposed to be. If the return path of the transient is weak, the the electricity will find a better path and that might be more problematic.?
?
Rule to follow - no extension cords on surge protecting power strips.?
?
Why? Because now you are hoping the ground connection on the power strip with a surge protector has a good ground connection and it it doesn't as it adds impedance to the circuit and that can make things worse (pulses decrease, but pulse width lengthens).
?
Ground is a reference point. We call it ground because that is what was used and is still used for many applications. In power circuits, it is useful to think of have a hot line, a return line, and a ground line. Inside electronic systems we also think of things the same way, though we might refer to the ground of the system to actually be the return and an actual ground connection is used a different way.
-- Buffalo John
|
Thanks Buffalo John
for your good lesson, I learned news and refresh old knowledge that was lost.
With few words: Ground cable is important, and it have to be good.
/johannes
toggle quoted message
Show quoted text
See my answers below in red:
When in doubt, keep it simple, make sure your protection devices have all the proper connections to work, make sure your building wiring is strong enough to support your application (wiring size, breaker type and size, panel wiring,
panel balance, etc. etc. etc.), and when in doubt - ask.
On Sat, May 18, 2024 at 9:56?AM Johannes wrote:
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)
Yes, getting a working ground is an important thing to fix.
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?
Attaching to interior piping of a building was used in the past because that copper pipe ran outside into the actual ground. However, it is not a good way to make a ground connection because there are many ways it can be ineffective
or dangerous.And - you might not have a copper pipe going outside anymore. My son had his house repiped and the copper going outside was replaced with PEX.
What you need is to have the ground circuit actually connected to an EARTH return - which means a "ground" rod driven into the ground, near the electrical panel, with a heavy gauge wire connecting the rod to the panel. Grounds within
the building also need to be wired and not assumed to be connected by conduit.
Is it that wild electricity shall blows the Fuse before it blows me?
Wild electricity is an interesting way to look at it!?
The purpose of the ground in these machine tools applications is to divert a live circuit to a safer place - ground. For example, suppose your motor overheats and the insulation is damaged. It is possible that the damaged insulation
lets the live power to the motor flow to the case of the motor. If someone were to touch the live circuit by touching the motor housing or something that is bolted to the motor and then also touch something that has a actual ground connection, it is possible
for current to flow between one touch to the other. If it is mains power, it can be lots of voltage and lots of current. While the fuse might blow when you become the bridge between hot and ground, more likely is that you would get a shock and worse - and
the fuse wouldn't blow.
A GFCI (Ground Fault Circuit Interrupter) breaker would have a better chance of stopping you from becoming the fusible link than a fuse.
An AFCI (Arc Fault Circuit Interrupter) breaker will also be useful when dealing with leakages as it can detect leakage from more than just ground.
Make a better stable AC ?
Grounds don't make the AC more stable, they just make a return path for errant current. The quality of the AC coming in is governed by the power transformer that connects to the power company, the wiring along the way, balancing of
the loads, etc. While phases are referenced to ground, locally it might be different and this topic is a bit more than I want to tackle here.?
We had a case where a link in a meter corroded (really old meter, really old house (knob and tube in places still live), and something took out the circuit in such a way that the 240 coming in to the old house didn't have a neutral
reference that was solid One side had 40v and the other 200v. That was a power company call but a bunch of equipment was destroyed by the overvoltage situation (including a couple of MOV surge protectors).
To be a reference point for what MOV etc. is doing ?
Many MOV circuits are using the ground as the place to dump the transients. In practice, this can have unintended consequences if the ground return isn't really good. Power strips with cords and MOVs work only if the ground in the
building wiring is solid and not tied to neutral anywhere but where it is supposed to be. If the return path of the transient is weak, the the electricity will find a better path and that might be more problematic.?
Rule to follow - no extension cords on surge protecting power strips.?
Why? Because now you are hoping the ground connection on the power strip with a surge protector has a good ground connection and it it doesn't as it adds impedance to the circuit and that can make things worse (pulses decrease, but
pulse width lengthens).
Ground is a reference point. We call it ground because that is what was used
and is still used for many applications. In power circuits, it is useful to think of have a hot line, a return line, and a ground line. Inside electronic systems we also think of things the same way,
though we might refer to the ground of the system to actually be the return and an actual ground connection is used a different way.
--
Buffalo John
|
I agree power strip with surge protection inside is best way go and turn off power before you leave your hobby shop.?
I to have lights on strip and all power tools it also to stop fire.?
Just think of leave with solder iron. But light on solder in strip and turn off lights no power to iron. It keeps the lathe safe from power spikes.
Maybe it should in title the Plus of Power Strip for mini lathes
I was writing about because I do want any to have to buy a $150.00 and up power board for a mini lathe.?
|
I agree?
It is part of a mini lathe
But it is also part of lot of electronics.?
I said in beginning? I found a power strip is best way to go for mini lathes and all other electronics.
Some do wonder why.?
Unless have very old mini lathe using a AC motors you will have those problem?
Just a part of today's life.?
Dave?
toggle quoted message
Show quoted text
On Sun, May 19, 2024 at 09:23 AM, Miket_NYC wrote:
You guys are all very knowledgeable, but aren't we getting a bit far afield from minilathes? As for me, I have my machines and lights in my basement shop plugged into a power strip above my workbench and I shut it off when I'm done for the day.?
On Sat, May 18, 2024, 11:57 PM davesmith1800 via <davesmith1= [email protected]> wrote: I do live in California so know all probles .
I also look into solar. The only way pay if you install your self and it used off grid.?
Dave?
On Fri, May 17, 2024 at 03:14 PM, Chris Albertson wrote:
Looks like plugs in every time to place it by a electrician.?
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
?
?
Pocket-change in California. ? Broker commision is $50K and taxes are $30K per year. ? ?
?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
Dave? On Fri, May 17, 2024 at 11:41 AM, Chris Albertson wrote:
Are those whole house units still only one use ?
?
One use? ? You mean like a fuse? ? No.? They come with some kind of warranty but likely last forever. ? Link below is to a brand sold at Home Depot.? It is the plug-in kind and only works with their brand. ? ?Every brand has these and installation is trivial if you have space in the panel.? Oh, notice the “replace” light. ? I guess it is concievable it might go on after just one direct hit by lightening but more likey it will live in the panel for 30 or 50 years.
?
The OTHER thing that is now required is “combined GFCI arc-fault breakers". ? People hate them because of nuisance trips.? They cost $100 each and you might need a couple dozen of them. if you are putting in a pen panel.? They add $1,000 to a typical job. ? But there is no possible way to ever have an electrical fire or electrocution.? So they are worth the added $1K.
?
As long as we are at it.? In Calif. all new contruction must have solar panels on the roof.
?
?
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.
?
?
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
?
?
|
You guys are all very knowledgeable, but aren't we getting a bit far afield from minilathes? As for me, I have my machines and lights in my basement shop plugged into a power strip above my workbench and I shut it off when I'm done for the day.?
On Sat, May 18, 2024, 11:57 PM davesmith1800 via <davesmith1= [email protected]> wrote: I do live in California so know all probles .
I also look into solar. The only way pay if you install your self and it used off grid.?
Dave?
On Fri, May 17, 2024 at 03:14 PM, Chris Albertson wrote:
Looks like plugs in every time to place it by a electrician.?
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
?
?
Pocket-change in California. ? Broker commision is $50K and taxes are $30K per year. ? ?
?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
Dave? On Fri, May 17, 2024 at 11:41 AM, Chris Albertson wrote:
Are those whole house units still only one use ?
?
One use? ? You mean like a fuse? ? No.? They come with some kind of warranty but likely last forever. ? Link below is to a brand sold at Home Depot.? It is the plug-in kind and only works with their brand. ? ?Every brand has these and installation is trivial if you have space in the panel.? Oh, notice the “replace” light. ? I guess it is concievable it might go on after just one direct hit by lightening but more likey it will live in the panel for 30 or 50 years.
?
The OTHER thing that is now required is “combined GFCI arc-fault breakers". ? People hate them because of nuisance trips.? They cost $100 each and you might need a couple dozen of them. if you are putting in a pen panel.? They add $1,000 to a typical job. ? But there is no possible way to ever have an electrical fire or electrocution.? So they are worth the added $1K.
?
As long as we are at it.? In Calif. all new contruction must have solar panels on the roof.
?
?
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.
?
?
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
?
?
|
Re: AC & Surge protectors
Here is a schematic use on mini lathes and most electronics . The biggest problem is it on board and remove.? If was by fuse it would real simple to change out.  Dave??
On Sat, May 18, 2024 at 08:16 PM, mike allen wrote:
Thanks John
animal
On 5/18/24 6:57 PM, BuffaloJohn wrote:
It's not the design, it is the device. A transient pulse needs to be dissipated. To do that, the MOV becomes a short and then when the voltage decreases, it can become a high resistance path again. However, when the conduction time is beyond a certain amount of energy, heating occurs and the crystalline structure of the MOV can crack, melt, etc. and the device has protected it's last time.
?
I dug up an old circuit of a surge suppressor we fielded:
This has both three and two lead MOVs. It also has redundancy since there are slight variations in performance of MOVs. Also, all the combinations of transient possibilities are protected.
?
This one is designed to let the MOV shorting out cause the isolation relay to disengage.
On Sat, May 18, 2024 at 5:09?PM davesmith1800 via <davesmith1= [email protected]> wrote: In technical terms the Varistor shorts out? (when a voltage spikes happen) flipping the breaker or burning out the fuse.?
So if not designed right you easly have fire because it gets very hot.?
Dave?
On Sat, May 18, 2024 at 04:58 PM, mike allen wrote:
Surge protectors aren't all equal . They said on the news just now the
fire was started at one of the surge protectors for a 3D printer I believe .
--
Buffalo John
|
I do live in California so know all probles .
I also look into solar. The only way pay if you install your self and it used off grid.?
Dave?
toggle quoted message
Show quoted text
On Fri, May 17, 2024 at 03:14 PM, Chris Albertson wrote:
On May 17, 2024, at 1:41?PM, davesmith1800 via groups.io <davesmith1@...> wrote:
Looks like plugs in every time to place it by a electrician.?
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
?
?
Pocket-change in California. ? Broker commision is $50K and taxes are $30K per year. ? ?
?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
Dave? On Fri, May 17, 2024 at 11:41 AM, Chris Albertson wrote:
On May 16, 2024, at 9:49?PM, mike allen via groups.io <animal@...> wrote:
Are those whole house units still only one use ?
?
One use? ? You mean like a fuse? ? No. ?They come with some kind of warranty but likely last forever. ? Link below is to a brand sold at Home Depot. ?It is the plug-in kind and only works with their brand. ? ?Every brand has these and installation is trivial if you have space in the panel. ?Oh, notice the “replace” light. ? I guess it is concievable it might go on after just one direct hit by lightening but more likey it will live in the panel for 30 or 50 years.
?
The OTHER thing that is now required is “combined GFCI arc-fault breakers". ? People hate them because of nuisance trips. ?They cost $100 each and you might need a couple dozen of them. if you are putting in a pen panel. ?They add $1,000 to a typical job. ? But there is no possible way to ever have an electrical fire or electrocution. ?So they are worth the added $1K.
?
As long as we are at it. ?In Calif. all new contruction must have solar panels on the roof.
?
?
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 groups.io <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
?
?
|
Re: AC & Surge protectors
Thanks John
animal
On 5/18/24 6:57 PM, BuffaloJohn wrote:
toggle quoted message
Show quoted text
It's not the design, it is the device. A transient pulse
needs to be dissipated. To do that, the MOV becomes a short
and then when the voltage decreases, it can become a high
resistance path again. However, when the conduction time is
beyond a certain amount of energy, heating occurs and the
crystalline structure of the MOV can crack, melt, etc. and the
device has protected it's last time.
I dug up an old circuit of a surge suppressor we fielded:
This has both three and two lead MOVs. It also has
redundancy since there are slight variations in performance of
MOVs. Also, all the combinations of transient possibilities
are protected.
This one is designed to let the MOV shorting out cause the
isolation relay to disengage.
On Sat, May 18, 2024 at
5:09?PM davesmith1800 via <davesmith1= [email protected]>
wrote:
In
technical terms the Varistor shorts out? (when a voltage
spikes happen) flipping the breaker or burning out the fuse.?
So if not designed right you easly have fire because it gets
very hot.?
Dave?
On Sat, May 18, 2024 at 04:58 PM, mike allen wrote:
Surge protectors aren't all equal . They said on
the news just now the
fire was started at one of the surge protectors for a 3D
printer I believe .
--
Buffalo John
|
Re: AC & Surge protectors
It's not the design, it is the device. A transient pulse needs to be dissipated. To do that, the MOV becomes a short and then when the voltage decreases, it can become a high resistance path again. However, when the conduction time is beyond a certain amount of energy, heating occurs and the crystalline structure of the MOV can crack, melt, etc. and the device has protected it's last time.
I dug up an old circuit of a surge suppressor we fielded: This has both three and two lead MOVs. It also has redundancy since there are slight variations in performance of MOVs. Also, all the combinations of transient possibilities are protected.
This one is designed to let the MOV shorting out cause the isolation relay to disengage.
On Sat, May 18, 2024 at 5:09?PM davesmith1800 via <davesmith1= [email protected]> wrote: In technical terms the Varistor shorts out? (when a voltage spikes happen) flipping the breaker or burning out the fuse.?
So if not designed right you easly have fire because it gets very hot.?
Dave?
On Sat, May 18, 2024 at 04:58 PM, mike allen wrote:
Surge protectors aren't all equal . They said on the news just now the
fire was started at one of the surge protectors for a 3D printer I believe .
--
Buffalo John
|
Re: AC & Surge protectors
In technical terms the Varistor shorts out? (when a voltage spikes happen) flipping the breaker or burning out the fuse.?
So if not designed right you easly have fire because it gets very hot.?
Dave?
toggle quoted message
Show quoted text
On Sat, May 18, 2024 at 04:58 PM, mike allen wrote:
Surge protectors aren't all equal . They said on the news just now the
fire was started at one of the surge protectors for a 3D printer I believe .
|
Surge protectors aren't all equal . They said on the news just now the
fire was started at one of the surge protectors for a 3D printer I believe .
|
I? read? discussion? for? week
I am electronician??
this is? familar? for? me
you? have? the right? solution
but? you? can? find? this? kind of? device? in? any? vintage? ?monitor? or? video? selector?
any? ''? sert? plus? a rien? ''? have? one? of? these? device? near? the en tray plug
easy to? identify?
a? slot? on? top?
free? no? money
it? is? the? first? part? I? recycling
jack 47? 71
|
See my answers below in red:
When in doubt, keep it simple, make sure your protection devices have all the proper connections to work, make sure your building wiring is strong enough to support your application (wiring size, breaker type and size, panel wiring, panel balance, etc. etc. etc.), and when in doubt - ask.
On Sat, May 18, 2024 at 9:56?AM Johannes wrote:
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)
Yes, getting a working ground is an important thing to fix.
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?
Attaching to interior piping of a building was used in the past because that copper pipe ran outside into the actual ground. However, it is not a good way to make a ground connection because there are many ways it can be ineffective or dangerous.And - you might not have a copper pipe going outside anymore. My son had his house repiped and the copper going outside was replaced with PEX.
What you need is to have the ground circuit actually connected to an EARTH return - which means a "ground" rod driven into the ground, near the electrical panel, with a heavy gauge wire connecting the rod to the panel. Grounds within the building also need to be wired and not assumed to be connected by conduit.
Is it that wild electricity shall blows the Fuse before it blows me?
Wild electricity is an interesting way to look at it!?
The purpose of the ground in these machine tools applications is to divert a live circuit to a safer place - ground. For example, suppose your motor overheats and the insulation is damaged. It is possible that the damaged insulation lets the live power to the motor flow to the case of the motor. If someone were to touch the live circuit by touching the motor housing or something that is bolted to the motor and then also touch something that has a actual ground connection, it is possible for current to flow between one touch to the other. If it is mains power, it can be lots of voltage and lots of current. While the fuse might blow when you become the bridge between hot and ground, more likely is that you would get a shock and worse - and the fuse wouldn't blow.
A GFCI (Ground Fault Circuit Interrupter) breaker would have a better chance of stopping you from becoming the fusible link than a fuse.
An AFCI (Arc Fault Circuit Interrupter) breaker will also be useful when dealing with leakages as it can detect leakage from more than just ground.
Make a better stable AC ?
Grounds don't make the AC more stable, they just make a return path for errant current. The quality of the AC coming in is governed by the power transformer that connects to the power company, the wiring along the way, balancing of the loads, etc. While phases are referenced to ground, locally it might be different and this topic is a bit more than I want to tackle here.?
We had a case where a link in a meter corroded (really old meter, really old house (knob and tube in places still live), and something took out the circuit in such a way that the 240 coming in to the old house didn't have a neutral reference that was solid One side had 40v and the other 200v. That was a power company call but a bunch of equipment was destroyed by the overvoltage situation (including a couple of MOV surge protectors).
To be a reference point for what MOV etc. is doing ?
Many MOV circuits are using the ground as the place to dump the transients. In practice, this can have unintended consequences if the ground return isn't really good. Power strips with cords and MOVs work only if the ground in the building wiring is solid and not tied to neutral anywhere but where it is supposed to be. If the return path of the transient is weak, the the electricity will find a better path and that might be more problematic.?
Rule to follow - no extension cords on surge protecting power strips.?
Why? Because now you are hoping the ground connection on the power strip with a surge protector has a good ground connection and it it doesn't as it adds impedance to the circuit and that can make things worse (pulses decrease, but pulse width lengthens).
Ground is a reference point. We call it ground because that is what was used
and is still used
for many applications. In power circuits, it is useful to think of have a hot line, a return line, and a ground line. Inside electronic systems we also think of things the same way, though we might refer to the ground of the system to actually be the return and an actual ground connection is used a different way.
-- Buffalo John
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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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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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I first found part on a Bridgeport mill DRO.
The DRO die and found this part.?
The DRO was new in 1980
A pain to replace.?
Today I would just cut part onto and use power strip.?
It still in my mini lathe so two backups.
Dave?
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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
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- MOV failures are usually short circuit, but it depends on how much energy was diverted. If a lightning strike occurs, it is possible for there to be multiple short duration pulses with short repetition times that the MOV will overheat and
crack. In these cases, the MOV is often an open circuit. We have witnessed many failures of MOVs where the MOV split and pieces of the MOV were separated in the equipment housing. Fortunately, none of our MOV failures caught fire, but I have seen examples
where there was heat damage to adjacent components.
- YES, MOVs are used on AC lines. To use them in a DC circuit for anything
- Clamping Voltage is a BIG problem. The claim that devices are designed for 1500V peak voltage when plugged into the grid is completely wrong. There are design specs for 1500V ISOLATION between legs, but that is not the same as handling a 1500V transient.
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:
1- 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
3- Clamping voltage is not a big problem: Electronic devices plugged to the grid are designed for withstanding at least 1500V peak. For indirect shocks on AC lines, typical surge waveform is very short: 8?s rise time & 20?S overall duration and, in home distribution
circuits, it rarely exceeds this value. There are other schemes, depending on the nature of the shock (direct or indirect) and the nature of the upstream protection.
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 wrote:
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.
--
Buffalo John
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davesmith1800
Johannes
BuffaloJohn