I've got a few cheap micromark surge protectors, and noticed they have a clamping voltage of 650V.
Anyone know where I can get a much lower one? I've heard of protectors as low as 270V, but I can't find any to buy.

--
You know you've spent too much time on the computer when you spill milk and the first thing you think is, 'Edit, Undo.'

On Mon, 24 Feb 2014 13:48:25 -0000, "Uncle Peter" wrote:

I've got a few cheap micromark surge protectors, and noticed they have a clamping voltage of 650V.
Anyone know where I can get a much lower one? I've heard of protectors as low as 270V, but I can't find any to buy.


For 230V RMS?

650 is the peal to peak equivalent, but I think it's just the peak
voltage that's relevant here, so anything less than 325v is no good,
and you are going to need some margin above that.

Don't know what micromark offer, but if it's just a few twopenny MOVs
I shouldn't bother.

On Mon, 24 Feb 2014 14:15:06 -0000, Graham. wrote:

On Mon, 24 Feb 2014 13:48:25 -0000, "Uncle Peter" wrote:

I've got a few cheap micromark surge protectors, and noticed they have a clamping voltage of 650V.
Anyone know where I can get a much lower one? I've heard of protectors as low as 270V, but I can't find any to buy.

For 230V RMS?

Yes.

650 is the peal to peak equivalent, but I think it's just the peak
voltage that's relevant here, so anything less than 325v is no good,
and you are going to need some margin above that.

Don't know what micromark offer, but if it's just a few twopenny MOVs
I shouldn't bother.

This: http://petersphotos.com/temp/surge.jpg

It's to protect computers. Looking at other surge protectors up to 100 quid (this one was 4 quid), nothing is lower than 650V. And some of the 100 quid ones are 750V!

Am I right in thinking 650V is rubbish? I mean the surge could double the peak supply voltage without the protector doing anything, and if the surge was more, it would clamp it down to double, which is enough to **** up a computer. Mind you if it's just the power supply caps that go bang, I suppose it doesn't matter. Does a PC power supply stop surges getting past it?

Or.... does 650V mean peak to peak as opposed to zero to peak?

--
Nagry: the state of emotion a woman is in when yelling at her husband

Uncle Peter presented the following explanation :
On Mon, 24 Feb 2014 14:15:06 -0000, Graham. wrote:

On Mon, 24 Feb 2014 13:48:25 -0000, "Uncle Peter" wrote:

I've got a few cheap micromark surge protectors, and noticed they have a
clamping voltage of 650V.
Anyone know where I can get a much lower one? I've heard of protectors as
low as 270V, but I can't find any to buy.

For 230V RMS?

Yes.

650 is the peal to peak equivalent, but I think it's just the peak
voltage that's relevant here, so anything less than 325v is no good,
and you are going to need some margin above that.

Don't know what micromark offer, but if it's just a few twopenny MOVs
I shouldn't bother.

This: http://petersphotos.com/temp/surge.jpg

It's to protect computers. Looking at other surge protectors up to 100 quid
(this one was 4 quid), nothing is lower than 650V. And some of the 100 quid
ones are 750V!

Am I right in thinking 650V is rubbish? I mean the surge could double the
peak supply voltage without the protector doing anything, and if the surge
was more, it would clamp it down to double, which is enough to **** up a
computer. Mind you if it's just the power supply caps that go bang, I
suppose it doesn't matter. Does a PC power supply stop surges getting past
it?

Absolutely not! I've just done a partial rebuild of a gaming machine
for someone that has cost United Utilities (their electricity supplier)
over £1,500 after it was hit by a voltage surge - same house also had
two TVs and a microwave oven blow up too. And about twelve other houses
were affected so not a happy time for UU.

Or.... does 650V mean peak to peak as opposed to zero to peak?

In article ,
Steve writes:
Uncle Peter presented the following explanation :
On Mon, 24 Feb 2014 14:15:06 -0000, Graham. wrote:

On Mon, 24 Feb 2014 13:48:25 -0000, "Uncle Peter" wrote:

I've got a few cheap micromark surge protectors, and noticed they have a
clamping voltage of 650V.
Anyone know where I can get a much lower one? I've heard of protectors as
low as 270V, but I can't find any to buy.

For 230V RMS?

Yes.

650 is the peal to peak equivalent, but I think it's just the peak
voltage that's relevant here, so anything less than 325v is no good,
and you are going to need some margin above that.

Don't know what micromark offer, but if it's just a few twopenny MOVs
I shouldn't bother.

This: http://petersphotos.com/temp/surge.jpg

It's to protect computers. Looking at other surge protectors up to 100 quid
(this one was 4 quid), nothing is lower than 650V. And some of the 100 quid
ones are 750V!

Am I right in thinking 650V is rubbish? I mean the surge could double the
peak supply voltage without the protector doing anything, and if the surge
was more, it would clamp it down to double, which is enough to **** up a
computer. Mind you if it's just the power supply caps that go bang, I
suppose it doesn't matter. Does a PC power supply stop surges getting past
it?

Absolutely not! I've just done a partial rebuild of a gaming machine
for someone that has cost United Utilities (their electricity supplier)
over £1,500 after it was hit by a voltage surge - same house also had
two TVs and a microwave oven blow up too. And about twelve other houses
were affected so not a happy time for UU.

This sounds like a loss of neutral fault, and a MOV is useless for
protecting against such a sustained fault - it will just burst into
flames if the fault goes over the clamping voltage (and they have
been known to start fires).

Consequently, the MOV must have a clamping voltage above the 3-phase
peak of 570V. Secondly, each time it takes a significant spike, its
clamping voltage drops a bit, and it must still remain over 570V after
this.

The device is used up a bit by each spike (unless the spike is tiny).

Finally, a MOV (or any surge supression) just across live and neutral
is remarkably ineffective for protecting against lightning, where the
spike tends to be between different services, such as the phone line
and mains, or mains and ground, etc. and not between live and neutral.
It won't generally protect against broken neutral (which sees the mains
voltage rise to up to 400V). Just what is it you are trying to protect
against?

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

Uncle Peter wrote:
On Mon, 24 Feb 2014 14:15:06 -0000, Graham. wrote:

On Mon, 24 Feb 2014 13:48:25 -0000, "Uncle Peter" wrote:

I've got a few cheap micromark surge protectors, and noticed they
have a clamping voltage of 650V.
Anyone know where I can get a much lower one? I've heard of
protectors as low as 270V, but I can't find any to buy.

For 230V RMS?

Yes.

650 is the peal to peak equivalent, but I think it's just the peak
voltage that's relevant here, so anything less than 325v is no good,
and you are going to need some margin above that.

Don't know what micromark offer, but if it's just a few twopenny MOVs
I shouldn't bother.

This: http://petersphotos.com/temp/surge.jpg

It's to protect computers. Looking at other surge protectors up to 100
quid (this one was 4 quid), nothing is lower than 650V. And some of the
100 quid ones are 750V!

Am I right in thinking 650V is rubbish? I mean the surge could double
the peak supply voltage without the protector doing anything, and if the
surge was more, it would clamp it down to double, which is enough to
**** up a computer. Mind you if it's just the power supply caps that go
bang, I suppose it doesn't matter. Does a PC power supply stop surges
getting past it?

Or.... does 650V mean peak to peak as opposed to zero to peak?


Computers are designed to withstand about 2.5KV spikes and survive
minor lightning strikes. A 650V surge protector is quite adeaquate, but
might not last long as my local supply frquently gets 1500V fast
transients (microseconds), zero to peak. The surge protector is
bidirectional, ie it doesn't care which way round the volts are. The
current flowing is purely determined by the source impedance, which for
lightning strikes is close to zero if local. For interference spikes,
surge protectors work OK, but if your supply is cables in the air, then
they may well fail quite soon. My worst experiences have been "brown
outs", where the supply suddenly reverses phase or skips cycles, which
causes transformer saturation and doubles the peak supply volts(up to
700V zero to peak) for a cycle, which then takes a few cycles to settle
down. This also buggers up switched mode PSUs, which don't like having
their dc supply briefly doubled. If this happens, no surge protector
will operate correctly and survive. IME, unless you have a transformer
fed supply with a good UPS you are going to lose a few PSUs with the
current state of our electricity supply. I lost a couple last year. Just
be thankful you are not in the US, where lightning strikes are common
and the supply is frequently crap as well.

On Mon, 24 Feb 2014 15:24:57 -0000, Andrew Gabriel wrote:

In article ,
Steve writes:
Uncle Peter presented the following explanation :
On Mon, 24 Feb 2014 14:15:06 -0000, Graham. wrote:

On Mon, 24 Feb 2014 13:48:25 -0000, "Uncle Peter" wrote:

I've got a few cheap micromark surge protectors, and noticed they have a
clamping voltage of 650V.
Anyone know where I can get a much lower one? I've heard of protectors as
low as 270V, but I can't find any to buy.

For 230V RMS?

Yes.

650 is the peal to peak equivalent, but I think it's just the peak
voltage that's relevant here, so anything less than 325v is no good,
and you are going to need some margin above that.

Don't know what micromark offer, but if it's just a few twopenny MOVs
I shouldn't bother.

This: http://petersphotos.com/temp/surge.jpg

It's to protect computers. Looking at other surge protectors up to 100 quid
(this one was 4 quid), nothing is lower than 650V. And some of the 100 quid
ones are 750V!

Am I right in thinking 650V is rubbish? I mean the surge could double the
peak supply voltage without the protector doing anything, and if the surge
was more, it would clamp it down to double, which is enough to **** up a
computer. Mind you if it's just the power supply caps that go bang, I
suppose it doesn't matter. Does a PC power supply stop surges getting past
it?

Absolutely not! I've just done a partial rebuild of a gaming machine
for someone that has cost United Utilities (their electricity supplier)
over £1,500 after it was hit by a voltage surge - same house also had
two TVs and a microwave oven blow up too. And about twelve other houses
were affected so not a happy time for UU.

This sounds like a loss of neutral fault, and a MOV is useless for
protecting against such a sustained fault - it will just burst into
flames if the fault goes over the clamping voltage (and they have
been known to start fires).

I've seen that. At my 2nd last place of work, an electrician mixed up the wiring as they had some old colours and some new, causing L1 and L2 to be connected to a ring of 13A sockets instead of L1 and neutral. A surge protected plug on a digital projector melted, and the bulk capacitors in all 20 computers in the room burst (they had no surge protectors), giving off some stinky smoke. All this tripped the circuit breaker for the room, which presumably stopped any further damage or a fire. After I replaced all the capacitors, the computers were fine.

Consequently, the MOV must have a clamping voltage above the 3-phase
peak of 570V.

Why? If I get a momentary spike or surge between single phase peak and three phase peak, I want it removed. Also one above the 3-phase peak I want clamped down to the 1-phase peak, not the 3-phase peak!

Secondly, each time it takes a significant spike, its
clamping voltage drops a bit, and it must still remain over 570V after
this.

The device is used up a bit by each spike (unless the spike is tiny).

Finally, a MOV (or any surge supression) just across live and neutral
is remarkably ineffective for protecting against lightning, where the
spike tends to be between different services, such as the phone line
and mains, or mains and ground, etc. and not between live and neutral.

This one claims to be across any pair of pins. I thought they all were.

It won't generally protect against broken neutral (which sees the mains
voltage rise to up to 400V).

Why does it rise? If there was no neutral, and the load on all three phases was equal, nobody would notice. You'd get a rise (or fall) if your phase was not the same as the other two.

Just what is it you are trying to protect against?

A spike or surge. I don't want it just trimmed to 650V! The spike is still there!!

--
I'm not so think as you drunk I am...

On Mon, 24 Feb 2014 14:57:45 -0000, Steve wrote:

Uncle Peter presented the following explanation :
On Mon, 24 Feb 2014 14:15:06 -0000, Graham. wrote:

On Mon, 24 Feb 2014 13:48:25 -0000, "Uncle Peter" wrote:

I've got a few cheap micromark surge protectors, and noticed they have a
clamping voltage of 650V.
Anyone know where I can get a much lower one? I've heard of protectors as
low as 270V, but I can't find any to buy.

For 230V RMS?

Yes.

650 is the peal to peak equivalent, but I think it's just the peak
voltage that's relevant here, so anything less than 325v is no good,
and you are going to need some margin above that.

Don't know what micromark offer, but if it's just a few twopenny MOVs
I shouldn't bother.

This: http://petersphotos.com/temp/surge.jpg

It's to protect computers. Looking at other surge protectors up to 100 quid
(this one was 4 quid), nothing is lower than 650V. And some of the 100 quid
ones are 750V!

Am I right in thinking 650V is rubbish? I mean the surge could double the
peak supply voltage without the protector doing anything, and if the surge
was more, it would clamp it down to double, which is enough to **** up a
computer. Mind you if it's just the power supply caps that go bang, I
suppose it doesn't matter. Does a PC power supply stop surges getting past
it?

Absolutely not! I've just done a partial rebuild of a gaming machine
for someone that has cost United Utilities (their electricity supplier)
over £1,500 after it was hit by a voltage surge - same house also had
two TVs and a microwave oven blow up too. And about twelve other houses
were affected so not a happy time for UU.

Maybe it depends how long the surge was. See my other post (reply to a reply to yours) where a room full of computers was fine when connected to two phases by mistake. Just the bulk capacitors in the PSUs blew. I've also accidentally connected a printer and a computer to 240V instead of 110V when the switch was incorrectly set at the back. Also I've seen about 10 computers with the switch set wrongly on purpose by kids. Just a bang and a new capacitor required. I would have expected the fuse or breaker to blow before the voltage got through to the equipment in your case though - the bulk capacitors go short circuit?

--
The world's largest fruit are giant pumpkins. The world record is 1061lbs (481.3 kg).

On Mon, 24 Feb 2014 15:58:18 -0000, Capitol wrote:

Uncle Peter wrote:
On Mon, 24 Feb 2014 14:15:06 -0000, Graham. wrote:

On Mon, 24 Feb 2014 13:48:25 -0000, "Uncle Peter" wrote:

I've got a few cheap micromark surge protectors, and noticed they
have a clamping voltage of 650V.
Anyone know where I can get a much lower one? I've heard of
protectors as low as 270V, but I can't find any to buy.

For 230V RMS?

Yes.

650 is the peal to peak equivalent, but I think it's just the peak
voltage that's relevant here, so anything less than 325v is no good,
and you are going to need some margin above that.

Don't know what micromark offer, but if it's just a few twopenny MOVs
I shouldn't bother.

This: http://petersphotos.com/temp/surge.jpg

It's to protect computers. Looking at other surge protectors up to 100
quid (this one was 4 quid), nothing is lower than 650V. And some of the
100 quid ones are 750V!

Am I right in thinking 650V is rubbish? I mean the surge could double
the peak supply voltage without the protector doing anything, and if the
surge was more, it would clamp it down to double, which is enough to
**** up a computer. Mind you if it's just the power supply caps that go
bang, I suppose it doesn't matter. Does a PC power supply stop surges
getting past it?

Or.... does 650V mean peak to peak as opposed to zero to peak?

Computers are designed to withstand about 2.5KV spikes and survive
minor lightning strikes. A 650V surge protector is quite adeaquate, but
might not last long as my local supply frquently gets 1500V fast
transients (microseconds), zero to peak. The surge protector is
bidirectional, ie it doesn't care which way round the volts are. The
current flowing is purely determined by the source impedance, which for
lightning strikes is close to zero if local. For interference spikes,
surge protectors work OK, but if your supply is cables in the air, then
they may well fail quite soon.

They're cheap, I don't care, and they have an LED to indicate they're still running.

My worst experiences have been "brown
outs", where the supply suddenly reverses phase or skips cycles, which
causes transformer saturation and doubles the peak supply volts(up to
700V zero to peak) for a cycle, which then takes a few cycles to settle
down. This also buggers up switched mode PSUs, which don't like having
their dc supply briefly doubled. If this happens, no surge protector
will operate correctly and survive.

Explain how the phase can get reversed?

And why not have a surge protector that absorbs anything over 340V? Yes it wouldn't protect an extended double voltage, but it would remove more of the spikes.

IME, unless you have a transformer
fed supply with a good UPS you are going to lose a few PSUs with the
current state of our electricity supply. I lost a couple last year. Just
be thankful you are not in the US, where lightning strikes are common
and the supply is frequently crap as well.

I've got a good UPS on the only computer with data on it, but that was mainly to stop it going off if there was a short powercut for a second or two, which I get a lot of in bad weather. I've never known a power supply break here.

--
Father walks into his son's room and starts talking.
"Son, masturbating will cause you to go blind."
"But dad, I'm over here!"

On Mon, 24 Feb 2014 14:15:06 +0000, Graham. wrote:

650 is the peal to peak equivalent, but I think it's just the peak
voltage that's relevant here, so anything less than 325v is no good,
and you are going to need some margin above that.

Aye mains voltage spec is 230 V -6% +10% or 216 to 253 V. The peak
for 253 is 358 V.

--
Cheers
Dave.

Dave Liquorice was thinking very hard :
Aye mains voltage spec is 230 V -6% +10% or 216 to 253 V. The peak
for 253 is 358 V.

All they are intended to do is temporarily short out a brief surge,
maybe even long enough to pop the fuse, after which they (the MOV) need
to be replaced. In many cases, without having the means to none
destructively test them, you will not even know the MOV has failed.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

On 24/02/2014 13:48, Uncle Peter wrote:
I've got a few cheap micromark surge protectors, and noticed they have a
clamping voltage of 650V.
Anyone know where I can get a much lower one? I've heard of protectors
as low as 270V, but I can't find any to buy.

I feel you are on a loser here. Most power supplies can withstand modest
surges in their own right.

Surge protectors offer minimal protection, though I guess any is better
than none.

The voltages you quote are way of the mark. 650V is chosen for perfectly
good reasons.

If you want true protections then you should be looking at an Online UPS.

http://en.wikipedia.org/wiki/Uninter...ble-conversion


At least if that goes down, your equipment will still be working, and
furthermore will offer protection against power outages.

On Mon, 24 Feb 2014 16:59:24 -0000, Fredxxx wrote:

On 24/02/2014 13:48, Uncle Peter wrote:
I've got a few cheap micromark surge protectors, and noticed they have a
clamping voltage of 650V.
Anyone know where I can get a much lower one? I've heard of protectors
as low as 270V, but I can't find any to buy.

I feel you are on a loser here. Most power supplies can withstand modest
surges in their own right.

Surge protectors offer minimal protection, though I guess any is better
than none.

The voltages you quote are way of the mark. 650V is chosen for perfectly
good reasons.

What are the reasons? I can't find any details about clamping voltage online, just a brief description of what it is.

--
Cetus: What were you doing in the flooded sections of the city?
O'Neill: The backstroke
Talus: What are you planning?
O'Neill: I was planning to retire.

Uncle Peter wrote:
On Mon, 24 Feb 2014 16:59:24 -0000, Fredxxx wrote:

On 24/02/2014 13:48, Uncle Peter wrote:
I've got a few cheap micromark surge protectors, and noticed they have a
clamping voltage of 650V.
Anyone know where I can get a much lower one? I've heard of protectors
as low as 270V, but I can't find any to buy.

I feel you are on a loser here. Most power supplies can withstand modest
surges in their own right.

Surge protectors offer minimal protection, though I guess any is better
than none.

The voltages you quote are way of the mark. 650V is chosen for perfectly
good reasons.

What are the reasons? I can't find any details about clamping voltage
online, just a brief description of what it is.


Because under fault conditions the mains peak can reach 700V. This is
very rare, so 650V is a reasonable compromise. I suggest you look up
varistor characteristics for more information.

In article ,
"Uncle Peter" writes:
Just what is it you are trying to protect against?

A spike or surge. I don't want it just trimmed to 650V! The spike is s=
till there!!

Then you need an online UPS.
Not cheap, but this isn't a level of protection most things need.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

On Mon, 24 Feb 2014 17:23:54 -0000, Andrew Gabriel wrote:

In article ,
"Uncle Peter" writes:
Just what is it you are trying to protect against?

A spike or surge. I don't want it just trimmed to 650V! The spike is s=
till there!!

Then you need an online UPS.
Not cheap, but this isn't a level of protection most things need.

I would have thought doubling the voltage was bad for a lot of things.

--
Is it just a coincidence that Christianity and insanity end with the same letters?

On Mon, 24 Feb 2014 17:18:51 -0000, Capitol wrote:

Uncle Peter wrote:
On Mon, 24 Feb 2014 16:59:24 -0000, Fredxxx wrote:

On 24/02/2014 13:48, Uncle Peter wrote:
I've got a few cheap micromark surge protectors, and noticed they have a
clamping voltage of 650V.
Anyone know where I can get a much lower one? I've heard of protectors
as low as 270V, but I can't find any to buy.

I feel you are on a loser here. Most power supplies can withstand modest
surges in their own right.

Surge protectors offer minimal protection, though I guess any is better
than none.

The voltages you quote are way of the mark. 650V is chosen for perfectly
good reasons.

What are the reasons? I can't find any details about clamping voltage
online, just a brief description of what it is.

Because under fault conditions the mains peak can reach 700V. This is
very rare, so 650V is a reasonable compromise. I suggest you look up
varistor characteristics for more information.

Exactly, "fault conditions". Surely the point of a surge protector is to remove faults? Maybe it won't last long, but even if it sacrifices itself, and trips the breaker, you've save the more expensive equipment. What I seem to have here should be called a spike protector.

--
Peter is listening to "Who's the best - DJ Mad Dog feat. Tommyknocker"

On 24/02/2014 17:33, Uncle Peter wrote:
On Mon, 24 Feb 2014 17:18:51 -0000, Capitol wrote:

Uncle Peter wrote:
On Mon, 24 Feb 2014 16:59:24 -0000, Fredxxx wrote:

On 24/02/2014 13:48, Uncle Peter wrote:
I've got a few cheap micromark surge protectors, and noticed they
have a
clamping voltage of 650V.
Anyone know where I can get a much lower one? I've heard of protectors
as low as 270V, but I can't find any to buy.

I feel you are on a loser here. Most power supplies can withstand
modest
surges in their own right.

Surge protectors offer minimal protection, though I guess any is better
than none.

The voltages you quote are way of the mark. 650V is chosen for
perfectly
good reasons.

What are the reasons? I can't find any details about clamping voltage
online, just a brief description of what it is.

Because under fault conditions the mains peak can reach 700V. This is
very rare, so 650V is a reasonable compromise. I suggest you look up
varistor characteristics for more information.

Exactly, "fault conditions". Surely the point of a surge protector is
to remove faults? Maybe it won't last long, but even if it sacrifices
itself, and trips the breaker, you've save the more expensive
equipment. What I seem to have here should be called a spike protector.

Mains impedance is very low with a short circuit current measured in kA,
so a MOV has to dissipate a lot of energy if it should start to conduct.

How big an MOV do you want to use, or how many?

Unless you have a crowbar type of protection no breaker is ever going to
open under a fault condition before it's all too late.

A surge protector does not remove faults. It merely reduces the symptoms
of a fault. A bit like closing a stable door whilst the horse is escaping.

On Mon, 24 Feb 2014 17:43:21 -0000, Fredxxx wrote:

On 24/02/2014 17:33, Uncle Peter wrote:
On Mon, 24 Feb 2014 17:18:51 -0000, Capitol wrote:

Uncle Peter wrote:
On Mon, 24 Feb 2014 16:59:24 -0000, Fredxxx wrote:

On 24/02/2014 13:48, Uncle Peter wrote:


I feel you are on a loser here. Most power supplies can withstand
modest
surges in their own right.

Surge protectors offer minimal protection, though I guess any is better
than none.

The voltages you quote are way of the mark. 650V is chosen for
perfectly
good reasons.

What are the reasons? I can't find any details about clamping voltage
online, just a brief description of what it is.

Because under fault conditions the mains peak can reach 700V. This is
very rare, so 650V is a reasonable compromise. I suggest you look up
varistor characteristics for more information.

Exactly, "fault conditions". Surely the point of a surge protector is
to remove faults? Maybe it won't last long, but even if it sacrifices
itself, and trips the breaker, you've save the more expensive
equipment. What I seem to have here should be called a spike protector.

Mains impedance is very low with a short circuit current measured in kA,
so a MOV has to dissipate a lot of energy if it should start to conduct.

How big an MOV do you want to use, or how many?

Unless you have a crowbar type of protection no breaker is ever going to
open under a fault condition before it's all too late.

Oh, I assumed that the surge protector could handle a huge current for long enough for the breaker to open.
http://petersphotos.com/temp/surge.jpg
It says 9000A, 240J. Could that trip a breaker?

A surge protector does not remove faults. It merely reduces the symptoms
of a fault. A bit like closing a stable door whilst the horse is escaping.

Can you get a crowbar surge protector that would blow the 13A plug fuse or the 30A breaker?

--
A boomerang that doesn't come back is a stick.

Capitol submitted this idea :
Uncle Peter wrote:
On Mon, 24 Feb 2014 16:59:24 -0000, Fredxxx wrote:

On 24/02/2014 13:48, Uncle Peter wrote:
I've got a few cheap micromark surge protectors, and noticed they have a
clamping voltage of 650V.
Anyone know where I can get a much lower one? I've heard of protectors
as low as 270V, but I can't find any to buy.

I feel you are on a loser here. Most power supplies can withstand modest
surges in their own right.

Surge protectors offer minimal protection, though I guess any is better
than none.

The voltages you quote are way of the mark. 650V is chosen for perfectly
good reasons.

What are the reasons? I can't find any details about clamping voltage
online, just a brief description of what it is.


Because under fault conditions the mains peak can reach 700V. This is very
rare, so 650V is a reasonable compromise. I suggest you look up varistor
characteristics for more information.

That is a much better description of what they can effectively deal
short spikes with very little current behind the spikes.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

On Mon, 24 Feb 2014 18:09:48 -0000, Harry Bloomfield wrote:

Capitol submitted this idea :
Uncle Peter wrote:
On Mon, 24 Feb 2014 16:59:24 -0000, Fredxxx wrote:

On 24/02/2014 13:48, Uncle Peter wrote:
I've got a few cheap micromark surge protectors, and noticed they have a
clamping voltage of 650V.
Anyone know where I can get a much lower one? I've heard of protectors
as low as 270V, but I can't find any to buy.

I feel you are on a loser here. Most power supplies can withstand modest
surges in their own right.

Surge protectors offer minimal protection, though I guess any is better
than none.

The voltages you quote are way of the mark. 650V is chosen for perfectly
good reasons.

What are the reasons? I can't find any details about clamping voltage
online, just a brief description of what it is.


Because under fault conditions the mains peak can reach 700V. This is very
rare, so 650V is a reasonable compromise. I suggest you look up varistor
characteristics for more information.

That is a much better description of what they can effectively deal
short spikes with very little current behind the spikes.

But the short spikes will only be reduced to 650V will they not? I'd much rather they were reduced to 340V and lose a surge protector now and again.

--
In the beginning the Universe was created. This has made a lot of people very angry and been widely regarded as a bad move.

On Mon, 24 Feb 2014 18:09:48 -0000, Harry Bloomfield wrote:

Capitol submitted this idea :
Uncle Peter wrote:
On Mon, 24 Feb 2014 16:59:24 -0000, Fredxxx wrote:

On 24/02/2014 13:48, Uncle Peter wrote:
I've got a few cheap micromark surge protectors, and noticed they have a
clamping voltage of 650V.
Anyone know where I can get a much lower one? I've heard of protectors
as low as 270V, but I can't find any to buy.

I feel you are on a loser here. Most power supplies can withstand modest
surges in their own right.

Surge protectors offer minimal protection, though I guess any is better
than none.

The voltages you quote are way of the mark. 650V is chosen for perfectly
good reasons.

What are the reasons? I can't find any details about clamping voltage
online, just a brief description of what it is.


Because under fault conditions the mains peak can reach 700V. This is very
rare, so 650V is a reasonable compromise. I suggest you look up varistor
characteristics for more information.

That is a much better description of what they can effectively deal
short spikes with very little current behind the spikes.

http://en.wikipedia.org/wiki/Surge_p...amping_voltage
"The theoretical lowest possible let-through voltage for 120 V power lines was 180 V. New technology, high quality surge suppressors can now clamp voltage at 130 V."

--
In the beginning the Universe was created. This has made a lot of people very angry and been widely regarded as a bad move.

In article ,
"Uncle Peter" writes:
On Mon, 24 Feb 2014 17:23:54 -0000, Andrew Gabriel wrote:

In article ,
"Uncle Peter" writes:
Just what is it you are trying to protect against?

A spike or surge. I don't want it just trimmed to 650V! The spike is s=
till there!!

Then you need an online UPS.
Not cheap, but this isn't a level of protection most things need.

I would have thought doubling the voltage was bad for a lot of things.

Not a short spike. It won't get past the SMPSU storage capacitor.
(Power factor correction circuit might be slightly more vulnerable.)

A MOV won't handle anything longer than a short spike, without risk
of failing in an unsafe mode.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

On Mon, 24 Feb 2014 18:54:43 -0000, Andrew Gabriel wrote:

In article ,
"Uncle Peter" writes:
On Mon, 24 Feb 2014 17:23:54 -0000, Andrew Gabriel wrote:

In article ,
"Uncle Peter" writes:
Just what is it you are trying to protect against?

A spike or surge. I don't want it just trimmed to 650V! The spike is s=
till there!!

Then you need an online UPS.
Not cheap, but this isn't a level of protection most things need.

I would have thought doubling the voltage was bad for a lot of things.

Not a short spike. It won't get past the SMPSU storage capacitor.
(Power factor correction circuit might be slightly more vulnerable.)

Ok, I'll assume I've protected the computers well enough then. I've got a spike arrestor on the phoneline too.

A MOV won't handle anything longer than a short spike, without risk
of failing in an unsafe mode.

Oh. I assumed if it shorted it'd blow a fuse or breaker before it melted. I mean if you short a wire in a mains plug, the fuse blows before any hint of a fire.

--
Bad or missing mouse. Spank the cat [Y/N]?

Uncle Peter wrote:
On Mon, 24 Feb 2014 17:43:21 -0000, Fredxxx wrote:

On 24/02/2014 17:33, Uncle Peter wrote:
On Mon, 24 Feb 2014 17:18:51 -0000, Capitol wrote:

Uncle Peter wrote:
On Mon, 24 Feb 2014 16:59:24 -0000, Fredxxx wrote:

On 24/02/2014 13:48, Uncle Peter wrote:


I feel you are on a loser here. Most power supplies can withstand
modest
surges in their own right.

Surge protectors offer minimal protection, though I guess any is
better
than none.

The voltages you quote are way of the mark. 650V is chosen for
perfectly
good reasons.

What are the reasons? I can't find any details about clamping voltage
online, just a brief description of what it is.

Because under fault conditions the mains peak can reach 700V. This is
very rare, so 650V is a reasonable compromise. I suggest you look up
varistor characteristics for more information.

Exactly, "fault conditions". Surely the point of a surge protector is
to remove faults? Maybe it won't last long, but even if it sacrifices
itself, and trips the breaker, you've save the more expensive
equipment. What I seem to have here should be called a spike protector.

Mains impedance is very low with a short circuit current measured in kA,
so a MOV has to dissipate a lot of energy if it should start to conduct.

How big an MOV do you want to use, or how many?

Unless you have a crowbar type of protection no breaker is ever going to
open under a fault condition before it's all too late.

Oh, I assumed that the surge protector could handle a huge current for
long enough for the breaker to open.
http://petersphotos.com/temp/surge.jpg
It says 9000A, 240J. Could that trip a breaker?

A surge protector does not remove faults. It merely reduces the symptoms
of a fault. A bit like closing a stable door whilst the horse is
escaping.

Can you get a crowbar surge protector that would blow the 13A plug fuse
or the 30A breaker?


Yes, but it may well be too slow to protect the circuitry. Protection
is a risk reduction process, not a risk removal process.

On Mon, 24 Feb 2014 19:02:22 -0000, Capitol wrote:

Uncle Peter wrote:
On Mon, 24 Feb 2014 17:43:21 -0000, Fredxxx wrote:

On 24/02/2014 17:33, Uncle Peter wrote:
On Mon, 24 Feb 2014 17:18:51 -0000, Capitol wrote:

Uncle Peter wrote:




Because under fault conditions the mains peak can reach 700V. This is
very rare, so 650V is a reasonable compromise. I suggest you look up
varistor characteristics for more information.

Exactly, "fault conditions". Surely the point of a surge protector is
to remove faults? Maybe it won't last long, but even if it sacrifices
itself, and trips the breaker, you've save the more expensive
equipment. What I seem to have here should be called a spike protector.

Mains impedance is very low with a short circuit current measured in kA,
so a MOV has to dissipate a lot of energy if it should start to conduct.

How big an MOV do you want to use, or how many?

Unless you have a crowbar type of protection no breaker is ever going to
open under a fault condition before it's all too late.

Oh, I assumed that the surge protector could handle a huge current for
long enough for the breaker to open.
http://petersphotos.com/temp/surge.jpg
It says 9000A, 240J. Could that trip a breaker?

A surge protector does not remove faults. It merely reduces the symptoms
of a fault. A bit like closing a stable door whilst the horse is
escaping.

Can you get a crowbar surge protector that would blow the 13A plug fuse
or the 30A breaker?


Yes, but it may well be too slow to protect the circuitry. Protection
is a risk reduction process, not a risk removal process.

I guess it would need to be use in conjunction with other devices. What about a crowbar along with a MOV set to 350V?

--
Japanese scientists have created a camera with a shutter speed so fast, they can now photograph a woman with her mouth shut.

Uncle Peter wrote:
On Mon, 24 Feb 2014 18:09:48 -0000, Harry Bloomfield
wrote:

Capitol submitted this idea :
Uncle Peter wrote:
On Mon, 24 Feb 2014 16:59:24 -0000, Fredxxx wrote:

On 24/02/2014 13:48, Uncle Peter wrote:
I've got a few cheap micromark surge protectors, and noticed they
have a
clamping voltage of 650V.
Anyone know where I can get a much lower one? I've heard of
protectors
as low as 270V, but I can't find any to buy.

I feel you are on a loser here. Most power supplies can withstand
modest
surges in their own right.

Surge protectors offer minimal protection, though I guess any is
better
than none.

The voltages you quote are way of the mark. 650V is chosen for
perfectly
good reasons.

What are the reasons? I can't find any details about clamping voltage
online, just a brief description of what it is.


Because under fault conditions the mains peak can reach 700V. This is
very
rare, so 650V is a reasonable compromise. I suggest you look up varistor
characteristics for more information.

That is a much better description of what they can effectively deal
short spikes with very little current behind the spikes.

http://en.wikipedia.org/wiki/Surge_p...amping_voltage
"The theoretical lowest possible let-through voltage for 120 V power
lines was 180 V. New technology, high quality surge suppressors can now
clamp voltage at 130 V."


If the source impedance is low enough. Also, for many units 130V is the
level at which clamping starts, the let through voltage can be much
higher if it is a varistor system. Large Zener diodes have a lower
series resistance, but the clamping current can destroy the device if
large enough. Also, Zener diodes do not like RF energy, so lightning
strikes can destroy them at quite low levels of energy (punch through
occurs).

Capitol wrote:
Uncle Peter wrote:
On Mon, 24 Feb 2014 18:09:48 -0000, Harry Bloomfield
wrote:

Capitol submitted this idea :
Uncle Peter wrote:
On Mon, 24 Feb 2014 16:59:24 -0000, Fredxxx wrote:

On 24/02/2014 13:48, Uncle Peter wrote:
I've got a few cheap micromark surge protectors, and noticed they
have a
clamping voltage of 650V.
Anyone know where I can get a much lower one? I've heard of
protectors
as low as 270V, but I can't find any to buy.

I feel you are on a loser here. Most power supplies can withstand
modest
surges in their own right.

Surge protectors offer minimal protection, though I guess any is
better
than none.

The voltages you quote are way of the mark. 650V is chosen for
perfectly
good reasons.

What are the reasons? I can't find any details about clamping voltage
online, just a brief description of what it is.


Because under fault conditions the mains peak can reach 700V. This is
very
rare, so 650V is a reasonable compromise. I suggest you look up
varistor
characteristics for more information.

That is a much better description of what they can effectively deal
short spikes with very little current behind the spikes.

http://en.wikipedia.org/wiki/Surge_p...amping_voltage
"The theoretical lowest possible let-through voltage for 120 V power
lines was 180 V. New technology, high quality surge suppressors can now
clamp voltage at 130 V."


If the source impedance is low enough. Also, for many units 130V is the
level at which clamping starts, the let through voltage can be much
higher if it is a varistor system. Large Zener diodes have a lower
series resistance, but the clamping current can destroy the device if
large enough. Also, Zener diodes do not like RF energy, so lightning
strikes can destroy them at quite low levels of energy (punch through
occurs).

Correction If the source impedance id high enough.
Crowbars only protect to an extent, if the fuses arc through, the
crowbar will self destruct. That's why fuses have a breaking capacity
rating.

In article ,
Capitol writes:
If the source impedance is low enough. Also, for many units 130V is the
level at which clamping starts, the let through voltage can be much
higher if it is a varistor system. Large Zener diodes have a lower
series resistance, but the clamping current can destroy the device if
large enough. Also, Zener diodes do not like RF energy, so lightning
strikes can destroy them at quite low levels of energy (punch through
occurs).

Correction If the source impedance id high enough.
Crowbars only protect to an extent, if the fuses arc through, the
crowbar will self destruct. That's why fuses have a breaking capacity
rating.

The first minicomputers I worked on were switched off by crowbarring
the DC supplies. The original systems supported core store which is
non-volatile, but you don't want it to get scribbled on by the
computer collapsing in an uncontrolled way as the various voltage
rails decay. So, once the supply controller had decided the computer
was powering off (which lots of events could trigger), it told the
CPU so it could save the current registers to memory, and then it
crowbarred the supplies by shorting them out with large SCRs in a
controlled sequence, designed to protect the core store contents.

When you powered it up, if it was fitted with core store, it would
carry on running from where it stopped.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

In article , Harry
Bloomfield writes

All they are intended to do is temporarily short out a brief surge,
maybe even long enough to pop the fuse, after which they (the MOV) need
to be replaced. In many cases, without having the means to none
destructively test them, you will not even know the MOV has failed.

Time to trot this out again :-)

This is a photo of two failed 13A power strips. Each has two neons, one
to show 'power on' and another to show 'surge protection working'.

The 'SP working' neons were still lit despite the MOVs having vaporised
:-)

http://jasper.org.uk/pics/Boom.jpg

--
(\_/)
(='.'=)
(")_(")

In article ,
Mike Tomlinson writes:
In article , Harry
Bloomfield writes

All they are intended to do is temporarily short out a brief surge,
maybe even long enough to pop the fuse, after which they (the MOV) need
to be replaced. In many cases, without having the means to none
destructively test them, you will not even know the MOV has failed.

Time to trot this out again :-)

This is a photo of two failed 13A power strips. Each has two neons, one
to show 'power on' and another to show 'surge protection working'.

The 'SP working' neons were still lit despite the MOVs having vaporised
:-)

http://jasper.org.uk/pics/Boom.jpg

They've been responsible for some fires in the US, and I believe UL
are cracking down hard on MOV devices.

I know we had to stop using them in computer systems we manufactured
sometime around 1980, due to regulatory changes due to fire risk.

In power strips, they are a gimmick. Power strips are produced for
under £1. The MOV devices cost in the order of 10p in bulk, but
the addition of this 10p device enables you to market the power
strip for at least £5 more. Hence you can ship a higher margin
product, even though the added value pretty much useless.

I generally make a point of making sure power strips that I buy do
*not* have any MOV devices in them.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

replying to Uncle Peter , westom wrote:
no wrote:
"The theoretical lowest possible let-through voltage for 120 V power lines
was 180 V. New technology, high quality surge suppressors can now clamp
voltage at 130 V."
--
--

Learn what those numbers are actually report. Normal minimum let-through
voltage for 120 volt protectors is 330 volts. Normal let-through voltage
for 230 volts would be almost double that. 180 volts is reporting
something completely different.

Also appreciate what a protector does and does not do. For example,
excessive voltage by an electrician miswire would only destroy a protector
- do no protection. And if the protector's thermal fuse (not to be
confused with a 13 amp line fuse) does not trip fast enough, then a fire
may occur.

That protector only claims to protect from one type of anomaly that
typically causes no electronics damage. Due to robust protection already
inside appliances. Robust protection that even says why 650 volts during
a surge does not damage electronics.

The many who did not know 650 volts is a standard should cause you
pause. Since so many made recommendations without even knowing basics.

Finally, typically destructive surges can be hundreds of thousands of
joules. A protector adjacent to an appliance can only stop that current
or absorb that energy. How many joules does that protector claim to
absorb? Compare that number to hundreds of thousands of joules. Then ask
yourself, "What does it claim to do?" That should also give you pause.

You may want to learn of a completely different device (also called a
protector) that would address your concerns.


--

On Tue, 25 Feb 2014 12:53:26 +0000 (UTC),
(Andrew Gabriel) wrote:

In article ,
Mike Tomlinson writes:
In article , Harry
Bloomfield writes

All they are intended to do is temporarily short out a brief surge,
maybe even long enough to pop the fuse, after which they (the MOV) need
to be replaced. In many cases, without having the means to none
destructively test them, you will not even know the MOV has failed.

Time to trot this out again :-)

This is a photo of two failed 13A power strips. Each has two neons, one
to show 'power on' and another to show 'surge protection working'.

The 'SP working' neons were still lit despite the MOVs having vaporised
:-)

http://jasper.org.uk/pics/Boom.jpg

They've been responsible for some fires in the US, and I believe UL
are cracking down hard on MOV devices.

I know we had to stop using them in computer systems we manufactured
sometime around 1980, due to regulatory changes due to fire risk.

In power strips, they are a gimmick. Power strips are produced for
under £1. The MOV devices cost in the order of 10p in bulk, but
the addition of this 10p device enables you to market the power
strip for at least £5 more. Hence you can ship a higher margin
product, even though the added value pretty much useless.

I generally make a point of making sure power strips that I buy do
*not* have any MOV devices in them.


Its reassuring to know that my view on these things is shared by
someone as knowledgeable as you.

Here are my pictures
http://flic.kr/s/aHsjTjtS2A
What I was trying to illustrate here is how the L & N use the MOV PCB
as a junction block, relying on two blobs of best lead free solder.

If you were designing such a thing wouldn't you ferrule and spot weld
the incoming mains *directly* to the bus bars, and hang the PCB on the
bus bars separately?

On Tue, 25 Feb 2014 14:44:01 -0000, westom wrote:

replying to Uncle Peter , westom wrote:
no wrote:
"The theoretical lowest possible let-through voltage for 120 V power lines
was 180 V. New technology, high quality surge suppressors can now clamp
voltage at 130 V."

Learn what those numbers are actually report. Normal minimum let-through
voltage for 120 volt protectors is 330 volts. Normal let-through voltage
for 230 volts would be almost double that. 180 volts is reporting
something completely different.

Also appreciate what a protector does and does not do. For example,
excessive voltage by an electrician miswire would only destroy a protector
- do no protection. And if the protector's thermal fuse (not to be
confused with a 13 amp line fuse) does not trip fast enough, then a fire
may occur.

That protector only claims to protect from one type of anomaly that
typically causes no electronics damage. Due to robust protection already
inside appliances. Robust protection that even says why 650 volts during
a surge does not damage electronics.

The many who did not know 650 volts is a standard should cause you
pause. Since so many made recommendations without even knowing basics.

Finally, typically destructive surges can be hundreds of thousands of
joules. A protector adjacent to an appliance can only stop that current
or absorb that energy. How many joules does that protector claim to
absorb? Compare that number to hundreds of thousands of joules. Then ask
yourself, "What does it claim to do?" That should also give you pause.

You may want to learn of a completely different device (also called a
protector) that would address your concerns.


Surely if the surge protector could just short the line to anything that was over the 240V RMS, it would blow a fuse or breaker, and not cause a fire?

--
The Artist Formerly Known As Prince has a new album out.
It's called "The Songs Formerly Known As Hits."

On Monday, February 24, 2014 6:59:34 PM UTC, Uncle Peter wrote:


Ok, I'll assume I've protected the computers well enough then.

The designer & manufacturer of the PC PSU has done that.

I've got a spike arrestor on the phoneline too.

Overhead phone services already have those built in.

Youre buying into marketing bs and wasting your time.


NT

On Tue, 25 Feb 2014 17:14:55 -0000, wrote:

On Monday, February 24, 2014 6:59:34 PM UTC, Uncle Peter wrote:


Ok, I'll assume I've protected the computers well enough then.

The designer & manufacturer of the PC PSU has done that.

Then I guess the 4 quid surge protector is protecting several 40 quid PSUs.

I've got a spike arrestor on the phoneline too.

Overhead phone services already have those built in.

Youre buying into marketing bs and wasting your time.

Then why did my dad's network card burn out when he got lightning through his phone line, through the router, and into the ethernet port?

--
Does the Little Mermaid wear an algebra?

On Tuesday, February 25, 2014 5:21:05 PM UTC, Uncle Peter wrote:
On Tue, 25 Feb 2014 17:14:55 -0000, wrote:
On Monday, February 24, 2014 6:59:34 PM UTC, Uncle Peter wrote:


Ok, I'll assume I've protected the computers well enough then.

The designer & manufacturer of the PC PSU has done that.

Then I guess the 4 quid surge protector is protecting several 40 quid PSUs.

they dont protect anything, other than someone's profits

I've got a spike arrestor on the phoneline too.

Overhead phone services already have those built in.

Youre buying into marketing bs and wasting your time.

Then why did my dad's network card burn out when he got lightning through his phone line, through the router, and into the ethernet port?

Presumably because it was hit by lightning. No tiny surge arrestor can do anything about that.


NT

On Tue, 25 Feb 2014 17:54:32 -0000, wrote:

On Tuesday, February 25, 2014 5:21:05 PM UTC, Uncle Peter wrote:
On Tue, 25 Feb 2014 17:14:55 -0000, wrote:
On Monday, February 24, 2014 6:59:34 PM UTC, Uncle Peter wrote:


Ok, I'll assume I've protected the computers well enough then.

The designer & manufacturer of the PC PSU has done that.

Then I guess the 4 quid surge protector is protecting several 40 quid PSUs.

they dont protect anything, other than someone's profits

At 4 quid I very much doubt there is much profit. That includes postage and packing and packaging and Ebay fees.

I've got a spike arrestor on the phoneline too.

Overhead phone services already have those built in.

Youre buying into marketing bs and wasting your time.

Then why did my dad's network card burn out when he got lightning through his phone line, through the router, and into the ethernet port?

Presumably because it was hit by lightning. No tiny surge arrestor can do anything about that.

It might do enough to reduce the effect.

So, why did the plug in surge protector melt when at my 2nd last place of work an electrician put 2 phases onto a circuit instead of one? If they do nothing below 650V, it should have just sat there.

--
Do you know what a Jewish dilemma is?
Free ham.

Computer equipment sold in Europe needs to comply with EN55024 (Information technology equipment - Immunity characteristics - Limits and methods of measurement) to obtain CE marking.

This requires the following immunity on the mains input:
Surges: 1kV peak L to N, 2kV peak L or N to E
Fast transients: 1kV peak at 5kHz repetition rate.

Surges and transients are applied with both polarities and random phase relative to the mains waveform, so some of the surges are on top of the peak mains voltage.

Immunity in this case means that the equipment continues operating correctly after the test and that stored data has not been corrupted during the test.

On Tuesday, February 25, 2014 6:02:45 PM UTC, Uncle Peter wrote:
On Tue, 25 Feb 2014 17:54:32 -0000, wrote:
On Tuesday, February 25, 2014 5:21:05 PM UTC, Uncle Peter wrote:
On Tue, 25 Feb 2014 17:14:55 -0000, wrote:
On Monday, February 24, 2014 6:59:34 PM UTC, Uncle Peter wrote:

Then I guess the 4 quid surge protector is protecting several 40 quid PSUs.

they dont protect anything, other than someone's profits

At 4 quid I very much doubt there is much profit. That includes postage and packing and packaging and Ebay fees.

Of course there is, or they wouldnt be sold. Its basic capitalism principles. You can get them in retail quantities for 50p last time I looked.

I've got a spike arrestor on the phoneline too.

Overhead phone services already have those built in.

Youre buying into marketing bs and wasting your time.

Then why did my dad's network card burn out when he got lightning through his phone line, through the router, and into the ethernet port?

Presumably because it was hit by lightning. No tiny surge arrestor can do anything about that.

It might do enough to reduce the effect.

You've got sometimes a billion plus volts crossing over a mile of air. You've got maybe 300,000 amps. You've got a discharge path exceeding 50,000 degrees C. Do you seriously think a 1cm disc of any material on earth is going to make the slightest difference?

So, why did the plug in surge protector melt when at my 2nd last place of work an electrician put 2 phases onto a circuit instead of one? If they do nothing below 650V, it should have just sat there.

who cares? All you get for your money is a fire risk. Even the insurance that often comes with them is too often worthless, and at best worth very little. Its just a game, a profitable game.


NT