Silly question, AC power plugs

On Sun, 20 May 2012 11:14:55 -0400, krw@att.bizzzzzzzzzzzz wrote:

On Sun, 20 May 2012 07:37:17 -0700, Fred Abse
excretatauris@invalid.invalid> wrote:

On Wed, 16 May 2012 16:48:52 -0400, krw@att.bizzzzzzzzzzzz wrote:

On Wed, 16 May 2012 10:44:03 -0700, Fred Abse
excretatauris@invalid.invalid> wrote:

On Tue, 15 May 2012 16:19:44 -0400, Phil Hobbs wrote:

The British solved that problem by
the traditional method of "add mass until nothing breaks."

Shame they had to go for thick rectangular section pins with contact
only on two sides. About a third of the surface area wasted. The ones
I've come into contact (no pun) with seem to get rather hot on full
load.

Nasty clumsy things.

The German Schuko system seems to me to be superior.

Over-designed and too expensive. Typical German stuff.

I meant superior to the UK system, not necessarily to anywhere else.

The same applies. The US system is less robust than the UK, but it works
and is a lot cheaper. Over-engineered, isn't.
Click to expand...
I, too prefer the US system, having been subjected to many others, over
the years. As you say, not over-engineered, but fit for purpose. That's
what engineering is all about.

--
"For a successful technology, reality must take precedence
over public relations, for nature cannot be fooled."
(Richard Feynman)
 
On Sun, 20 May 2012 01:30:51 -0500, John Fields
<jfields@austininstruments.com> wrote:

On Sat, 19 May 2012 14:26:57 -0700, John Larkin
jjSNIPlarkin@highTHISlandtechnology.com> wrote:

On Sat, 19 May 2012 15:08:30 -0500, John Fields
jfields@austininstruments.com> wrote:

On Sat, 19 May 2012 09:49:10 -0700, John Larkin
jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

On Fri, 18 May 2012 09:54:03 -0500, John Fields
jfields@austininstruments.com> wrote:

On Thu, 17 May 2012 17:11:41 -0700, John Larkin
jlarkin@highlandtechnology.com> wrote:

On Thu, 17 May 2012 16:52:33 +0000 (UTC), Cydrome Leader
presence@MUNGEpanix.com> wrote:

John Fields <jfields@austininstruments.com> wrote:
On Tue, 15 May 2012 21:42:24 +0100, "Ian Field"
gangprobing.alien@ntlworld.com> wrote:


"Phil Hobbs" <pcdhSpamMeSenseless@electrooptical.net> wrote in message
news:4FB2BA60.381879AC@electrooptical.net...
news@jecarter.us wrote:

On Tue, 15 May 2012 11:22:21 -0700 (PDT), George Herold
gherold@teachspin.com> wrote:


Why do US 120 VAC power plugs have holes in the end of the blades?

George H.

To allow you to put the shackle of a small lock through the blade to
ensure the item can't be plugged in for use?

I suspect it's to mate with a small boss on the blades of the socket, to
make it less likely to jiggle loose. The British solved that problem by
the traditional method of "add mass until nothing breaks."


I always marvelled at how the Yanks got away with such flimsy plugs when
half the voltage means twice the current for the same load power.

---
A blade made of brass with a width of 1/4", a thickness of 1/16" and a
length of about an inch is hardly flimsy, and serves us well when we
opt to go to 240V and eke out four times the power available from the
mains without changing plugs.

is this some sort of metric math?


What's even more "shocking" than his math

---
Connect a 120 ohm resistor across 120V mains. How much power will it
dissipate? Call that P1.

Connect a 120 ohm resistor across 240V mains. How much power will it
dissipate? Call that P2.

Divide P2 by P1. What do you get?

Technically, the wrong answer.

---
What, you don't know how to divide???
---

---

is that he uses the same plug for 120 and for 240.

---
You've never done that?

NO!

---
I do it all the time Mr. Gutless!

That is, I have a 0 -> 140V 1.4kVA VARIAC connected to the paralleled
primaries of a 3kVA isolation transformer with the secondaries wired
in series, so I can get 0 -> 560 VRMS out of the transformer.

Its primaries and secondaries are wired to a terminal block with
ring-tongue terminal jumpers on the user side so I can change the
connections to the transformer as required.

In addition, the output of the transformer is fused and connected to
about 18" of zip cord terminated with a polarized two-terminal US
style AC receptacle.

Into that receptacle normally goes about an 8 foot long suicide cord
with copper mini-alligator clips (Mueller 30C) and vinyl boots
(Mueller BU-32-2) on the business end.

Want a picture?
---

If the plug is good for 10 amps, you can power a 1200 watt load from
120 volts. That same plug can power a 2400 watt load from 240 volts.

2:1 is the available-power ratio that you can "eke out" , not 4:1.

---
Sorry, Charlie, but you're cheating again by moving the goalposts.

2:1 is what's available with the load resistance variation of 2:1
which _you_ used, but not with the constant load resistance which _I_
used in my example.

For example: if the mains are 240V, the plug is good for 10 amps, and
the load is 2400 watts, then the load's resistance will be 24 ohms.

Plugging that 24 ohms into a 120V source would result in its
dissipating 600 watts, which is 1/4 the power it would have dissipated
were it connected across 240V mains.


You said this:


A blade made of brass with a width of 1/4", a thickness of 1/16" and a
length of about an inch is hardly flimsy, and serves us well when we
opt to go to 240V and eke out four times the power available from the
mains without changing plugs.

which is just wrong.

---
Right you are!

Changing just one word, though, would make it right.

Care to guess which one?
Click to expand...
Easy. Change "four" to "two."


--

John Larkin Highland Technology Inc
www.highlandtechnology.com jlarkin at highlandtechnology dot com

Precision electronic instrumentation
Picosecond-resolution Digital Delay and Pulse generators
Custom timing and laser controllers
Photonics and fiberoptic TTL data links
VME analog, thermocouple, LVDT, synchro, tachometer
Multichannel arbitrary waveform generators
 
On Sun, 20 May 2012 09:18:07 -0700, John Larkin
<jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

On Sun, 20 May 2012 01:30:51 -0500, John Fields
jfields@austininstruments.com> wrote:

On Sat, 19 May 2012 14:26:57 -0700, John Larkin
jjSNIPlarkin@highTHISlandtechnology.com> wrote:

On Sat, 19 May 2012 15:08:30 -0500, John Fields
jfields@austininstruments.com> wrote:

On Sat, 19 May 2012 09:49:10 -0700, John Larkin
jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

On Fri, 18 May 2012 09:54:03 -0500, John Fields
jfields@austininstruments.com> wrote:

On Thu, 17 May 2012 17:11:41 -0700, John Larkin
jlarkin@highlandtechnology.com> wrote:

On Thu, 17 May 2012 16:52:33 +0000 (UTC), Cydrome Leader
presence@MUNGEpanix.com> wrote:

John Fields <jfields@austininstruments.com> wrote:
On Tue, 15 May 2012 21:42:24 +0100, "Ian Field"
gangprobing.alien@ntlworld.com> wrote:


"Phil Hobbs" <pcdhSpamMeSenseless@electrooptical.net> wrote in message
news:4FB2BA60.381879AC@electrooptical.net...
news@jecarter.us wrote:

On Tue, 15 May 2012 11:22:21 -0700 (PDT), George Herold
gherold@teachspin.com> wrote:


Why do US 120 VAC power plugs have holes in the end of the blades?

George H.

To allow you to put the shackle of a small lock through the blade to
ensure the item can't be plugged in for use?

I suspect it's to mate with a small boss on the blades of the socket, to
make it less likely to jiggle loose. The British solved that problem by
the traditional method of "add mass until nothing breaks."


I always marvelled at how the Yanks got away with such flimsy plugs when
half the voltage means twice the current for the same load power.

---
A blade made of brass with a width of 1/4", a thickness of 1/16" and a
length of about an inch is hardly flimsy, and serves us well when we
opt to go to 240V and eke out four times the power available from the
mains without changing plugs.

is this some sort of metric math?


What's even more "shocking" than his math

---
Connect a 120 ohm resistor across 120V mains. How much power will it
dissipate? Call that P1.

Connect a 120 ohm resistor across 240V mains. How much power will it
dissipate? Call that P2.

Divide P2 by P1. What do you get?

Technically, the wrong answer.

---
What, you don't know how to divide???
---

---

is that he uses the same plug for 120 and for 240.

---
You've never done that?

NO!

---
I do it all the time Mr. Gutless!

That is, I have a 0 -> 140V 1.4kVA VARIAC connected to the paralleled
primaries of a 3kVA isolation transformer with the secondaries wired
in series, so I can get 0 -> 560 VRMS out of the transformer.

Its primaries and secondaries are wired to a terminal block with
ring-tongue terminal jumpers on the user side so I can change the
connections to the transformer as required.

In addition, the output of the transformer is fused and connected to
about 18" of zip cord terminated with a polarized two-terminal US
style AC receptacle.

Into that receptacle normally goes about an 8 foot long suicide cord
with copper mini-alligator clips (Mueller 30C) and vinyl boots
(Mueller BU-32-2) on the business end.

Want a picture?
---

If the plug is good for 10 amps, you can power a 1200 watt load from
120 volts. That same plug can power a 2400 watt load from 240 volts.

2:1 is the available-power ratio that you can "eke out" , not 4:1.

---
Sorry, Charlie, but you're cheating again by moving the goalposts.

2:1 is what's available with the load resistance variation of 2:1
which _you_ used, but not with the constant load resistance which _I_
used in my example.

For example: if the mains are 240V, the plug is good for 10 amps, and
the load is 2400 watts, then the load's resistance will be 24 ohms.

Plugging that 24 ohms into a 120V source would result in its
dissipating 600 watts, which is 1/4 the power it would have dissipated
were it connected across 240V mains.


You said this:


A blade made of brass with a width of 1/4", a thickness of 1/16" and a
length of about an inch is hardly flimsy, and serves us well when we
opt to go to 240V and eke out four times the power available from the
mains without changing plugs.

which is just wrong.

---
Right you are!

Changing just one word, though, would make it right.

Care to guess which one?

Easy. Change "four" to "two."
Click to expand...
That still leaves the "without changing plugs" part.
 
"Cydrome Leader" <presence@MUNGEpanix.com> wrote in message
news:jpbdhv$ngg$3@reader1.panix.com...
John Fields <jfields@austininstruments.com> wrote:
On Thu, 17 May 2012 16:52:33 +0000 (UTC), Cydrome Leader
presence@MUNGEpanix.com> wrote:

John Fields <jfields@austininstruments.com> wrote:
On Tue, 15 May 2012 21:42:24 +0100, "Ian Field"
gangprobing.alien@ntlworld.com> wrote:


"Phil Hobbs" <pcdhSpamMeSenseless@electrooptical.net> wrote in message
news:4FB2BA60.381879AC@electrooptical.net...
news@jecarter.us wrote:

On Tue, 15 May 2012 11:22:21 -0700 (PDT), George Herold
gherold@teachspin.com> wrote:


Why do US 120 VAC power plugs have holes in the end of the blades?

George H.

To allow you to put the shackle of a small lock through the blade to
ensure the item can't be plugged in for use?

I suspect it's to mate with a small boss on the blades of the socket,
to
make it less likely to jiggle loose. The British solved that problem
by
the traditional method of "add mass until nothing breaks."


I always marvelled at how the Yanks got away with such flimsy plugs
when
half the voltage means twice the current for the same load power.

---
A blade made of brass with a width of 1/4", a thickness of 1/16" and a
length of about an inch is hardly flimsy, and serves us well when we
opt to go to 240V and eke out four times the power available from the
mains without changing plugs.

is this some sort of metric math?

---
Well, we're not dealing with feet and inches, so you figure it out:

120V mains, 120 ohm load, 120 watts

240V mains, 120 ohm load, 480 watts

480
----- = 4
120


so you're telling me if an outlet is rated and fused to supply say 15 amps
at 120 volts, that if I double the voltage across it's supply it can now
safely handle 30 amps at 240?

What sort of jenky bullshit "instruments" to you make?
Click to expand...

He's an escaped loony who likes to pretend he's "professional people".
 
John Larkin <jjlarkin@highnotlandthistechnologypart.com> wrote:
On Fri, 18 May 2012 09:54:03 -0500, John Fields
jfields@austininstruments.com> wrote:

On Thu, 17 May 2012 17:11:41 -0700, John Larkin
jlarkin@highlandtechnology.com> wrote:

On Thu, 17 May 2012 16:52:33 +0000 (UTC), Cydrome Leader
presence@MUNGEpanix.com> wrote:

John Fields <jfields@austininstruments.com> wrote:
On Tue, 15 May 2012 21:42:24 +0100, "Ian Field"
gangprobing.alien@ntlworld.com> wrote:


"Phil Hobbs" <pcdhSpamMeSenseless@electrooptical.net> wrote in message
news:4FB2BA60.381879AC@electrooptical.net...
news@jecarter.us wrote:

On Tue, 15 May 2012 11:22:21 -0700 (PDT), George Herold
gherold@teachspin.com> wrote:


Why do US 120 VAC power plugs have holes in the end of the blades?

George H.

To allow you to put the shackle of a small lock through the blade to
ensure the item can't be plugged in for use?

I suspect it's to mate with a small boss on the blades of the socket, to
make it less likely to jiggle loose. The British solved that problem by
the traditional method of "add mass until nothing breaks."


I always marvelled at how the Yanks got away with such flimsy plugs when
half the voltage means twice the current for the same load power.

---
A blade made of brass with a width of 1/4", a thickness of 1/16" and a
length of about an inch is hardly flimsy, and serves us well when we
opt to go to 240V and eke out four times the power available from the
mains without changing plugs.

is this some sort of metric math?


What's even more "shocking" than his math

---
Connect a 120 ohm resistor across 120V mains. How much power will it
dissipate? Call that P1.

Connect a 120 ohm resistor across 240V mains. How much power will it
dissipate? Call that P2.

Divide P2 by P1. What do you get?

Technically, the wrong answer.


---

is that he uses the same plug for 120 and for 240.

---
You've never done that?

NO!

If the plug is good for 10 amps, you can power a 1200 watt load from
120 volts. That same plug can power a 2400 watt load from 240 volts.

2:1 is the available-power ratio that you can "eke out" , not 4:1.
Click to expand...
correct.

There are correct receptables and plugs for 240 volt use, I use those. Not
sure why anybody would ever not do that.
 
John Fields <jfields@austininstruments.com> wrote:
On Thu, 17 May 2012 16:52:33 +0000 (UTC), Cydrome Leader
presence@MUNGEpanix.com> wrote:

John Fields <jfields@austininstruments.com> wrote:
On Tue, 15 May 2012 21:42:24 +0100, "Ian Field"
gangprobing.alien@ntlworld.com> wrote:


"Phil Hobbs" <pcdhSpamMeSenseless@electrooptical.net> wrote in message
news:4FB2BA60.381879AC@electrooptical.net...
news@jecarter.us wrote:

On Tue, 15 May 2012 11:22:21 -0700 (PDT), George Herold
gherold@teachspin.com> wrote:


Why do US 120 VAC power plugs have holes in the end of the blades?

George H.

To allow you to put the shackle of a small lock through the blade to
ensure the item can't be plugged in for use?

I suspect it's to mate with a small boss on the blades of the socket, to
make it less likely to jiggle loose. The British solved that problem by
the traditional method of "add mass until nothing breaks."


I always marvelled at how the Yanks got away with such flimsy plugs when
half the voltage means twice the current for the same load power.

---
A blade made of brass with a width of 1/4", a thickness of 1/16" and a
length of about an inch is hardly flimsy, and serves us well when we
opt to go to 240V and eke out four times the power available from the
mains without changing plugs.

is this some sort of metric math?

---
Well, we're not dealing with feet and inches, so you figure it out:

120V mains, 120 ohm load, 120 watts

240V mains, 120 ohm load, 480 watts

480
----- = 4
120
Click to expand...
so you're telling me if an outlet is rated and fused to supply say 15 amps
at 120 volts, that if I double the voltage across it's supply it can now
safely handle 30 amps at 240?

What sort of jenky bullshit "instruments" to you make?
 
Michael A. Terrell <mike.terrell@earthlink.net> wrote:
Roger wrote:

fungus wrote:

They also thought to put on/off switches
on all the wall sockets - incredibly useful.

No, the Australian-New Zealand system is the best. The wall sockets
are all switched.


Who needs that? Is everything you plug in so low grade that you have
to turn off the outlet between uses? All I see is that it lowers the
reliability of every outlet by adding more parts. Rube Goldberg would
be proud of those outlets.
Click to expand...
That plus they're large and stupid.
 
Fred Abse <excretatauris@invalid.invalid> wrote:
On Thu, 17 May 2012 04:16:01 -0700, fungus wrote:

On Wednesday, May 16, 2012 7:44:03 PM UTC+2, Fred Abse wrote:

Nasty clumsy things.

The German Schuko system seems to me to be superior.


...apart from the fact that you can plug them in either way around (ie.
live/neutral swapped) causing massive sparks when you try to connect your
printer to your PC due to the difference in ground levels.

Any printer that has a low impedance path to neutral from ground would be illegal
in just about any jurisdiction.
The Schuko (Schutzkontakt) system has two safety ground connections at
right angles to the pins, That's what the side contacts are for. I suspect
you must have come across a mis-wired plug or socket.

Schutzkontakt = Protection Contact.

Do you honestly think that VDE, T?V, DIN, etc. would have missed such an
obvious thing?
Click to expand...
yeah, the creators of the mini-DIN connector (stupidest connector ever
created) don't really strike me being clever.
 
George Herold <gherold@teachspin.com> wrote:
On May 17, 12:33?pm, e...@whidbey.com wrote:
On Tue, 15 May 2012 11:22:21 -0700 (PDT), George Herold

gher...@teachspin.com> wrote:

Why do US 120 VAC power plugs have holes in the end of the blades?

George H.

The holes are so you can run a little wire through them to connect to
a power source without a receptacle. ?Just another variation of the
"suicide cord". I'm surprised you didn't know this as the suicide cord
is just basic electronics.
Eric

I've got a suicide plug. US AC prongs on one end, bannana plugs on
the other.
Scary!

George H.
Click to expand...
It's one of the most useful cables there is. Mine are made with red cable
so you know what it is from any end.
 
On Sun, 20 May 2012 19:53:39 +0100, "Ian Field"
<gangprobing.alien@ntlworld.com> wrote:

"Cydrome Leader" <presence@MUNGEpanix.com> wrote in message
news:jpbdhv$ngg$3@reader1.panix.com...
John Fields <jfields@austininstruments.com> wrote:
On Thu, 17 May 2012 16:52:33 +0000 (UTC), Cydrome Leader
presence@MUNGEpanix.com> wrote:

John Fields <jfields@austininstruments.com> wrote:
On Tue, 15 May 2012 21:42:24 +0100, "Ian Field"
gangprobing.alien@ntlworld.com> wrote:


"Phil Hobbs" <pcdhSpamMeSenseless@electrooptical.net> wrote in message
news:4FB2BA60.381879AC@electrooptical.net...
news@jecarter.us wrote:

On Tue, 15 May 2012 11:22:21 -0700 (PDT), George Herold
gherold@teachspin.com> wrote:


Why do US 120 VAC power plugs have holes in the end of the blades?

George H.

To allow you to put the shackle of a small lock through the blade to
ensure the item can't be plugged in for use?

I suspect it's to mate with a small boss on the blades of the socket,
to
make it less likely to jiggle loose. The British solved that problem
by
the traditional method of "add mass until nothing breaks."


I always marvelled at how the Yanks got away with such flimsy plugs
when
half the voltage means twice the current for the same load power.

---
A blade made of brass with a width of 1/4", a thickness of 1/16" and a
length of about an inch is hardly flimsy, and serves us well when we
opt to go to 240V and eke out four times the power available from the
mains without changing plugs.

is this some sort of metric math?

---
Well, we're not dealing with feet and inches, so you figure it out:

120V mains, 120 ohm load, 120 watts

240V mains, 120 ohm load, 480 watts

480
----- = 4
120


so you're telling me if an outlet is rated and fused to supply say 15 amps
at 120 volts, that if I double the voltage across it's supply it can now
safely handle 30 amps at 240?

What sort of jenky bullshit "instruments" to you make?


He's an escaped loony who likes to pretend he's "professional people".
Click to expand...
At least he's not an engineer.
 
On Sun, 20 May 2012 09:18:07 -0700, John Larkin
<jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

On Sun, 20 May 2012 01:30:51 -0500, John Fields
jfields@austininstruments.com> wrote:

On Sat, 19 May 2012 14:26:57 -0700, John Larkin
jjSNIPlarkin@highTHISlandtechnology.com> wrote:

On Sat, 19 May 2012 15:08:30 -0500, John Fields
jfields@austininstruments.com> wrote:

On Sat, 19 May 2012 09:49:10 -0700, John Larkin
jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

On Fri, 18 May 2012 09:54:03 -0500, John Fields
jfields@austininstruments.com> wrote:

On Thu, 17 May 2012 17:11:41 -0700, John Larkin
jlarkin@highlandtechnology.com> wrote:

On Thu, 17 May 2012 16:52:33 +0000 (UTC), Cydrome Leader
presence@MUNGEpanix.com> wrote:

John Fields <jfields@austininstruments.com> wrote:
On Tue, 15 May 2012 21:42:24 +0100, "Ian Field"
gangprobing.alien@ntlworld.com> wrote:


"Phil Hobbs" <pcdhSpamMeSenseless@electrooptical.net> wrote in message
news:4FB2BA60.381879AC@electrooptical.net...
news@jecarter.us wrote:

On Tue, 15 May 2012 11:22:21 -0700 (PDT), George Herold
gherold@teachspin.com> wrote:


Why do US 120 VAC power plugs have holes in the end of the blades?

George H.

To allow you to put the shackle of a small lock through the blade to
ensure the item can't be plugged in for use?

I suspect it's to mate with a small boss on the blades of the socket, to
make it less likely to jiggle loose. The British solved that problem by
the traditional method of "add mass until nothing breaks."


I always marvelled at how the Yanks got away with such flimsy plugs when
half the voltage means twice the current for the same load power.

---
A blade made of brass with a width of 1/4", a thickness of 1/16" and a
length of about an inch is hardly flimsy, and serves us well when we
opt to go to 240V and eke out four times the power available from the
mains without changing plugs.

is this some sort of metric math?


What's even more "shocking" than his math

---
Connect a 120 ohm resistor across 120V mains. How much power will it
dissipate? Call that P1.

Connect a 120 ohm resistor across 240V mains. How much power will it
dissipate? Call that P2.

Divide P2 by P1. What do you get?

Technically, the wrong answer.

---
What, you don't know how to divide???
---

---

is that he uses the same plug for 120 and for 240.

---
You've never done that?

NO!

---
I do it all the time Mr. Gutless!

That is, I have a 0 -> 140V 1.4kVA VARIAC connected to the paralleled
primaries of a 3kVA isolation transformer with the secondaries wired
in series, so I can get 0 -> 560 VRMS out of the transformer.

Its primaries and secondaries are wired to a terminal block with
ring-tongue terminal jumpers on the user side so I can change the
connections to the transformer as required.

In addition, the output of the transformer is fused and connected to
about 18" of zip cord terminated with a polarized two-terminal US
style AC receptacle.

Into that receptacle normally goes about an 8 foot long suicide cord
with copper mini-alligator clips (Mueller 30C) and vinyl boots
(Mueller BU-32-2) on the business end.

Want a picture?
---

If the plug is good for 10 amps, you can power a 1200 watt load from
120 volts. That same plug can power a 2400 watt load from 240 volts.

2:1 is the available-power ratio that you can "eke out" , not 4:1.

---
Sorry, Charlie, but you're cheating again by moving the goalposts.

2:1 is what's available with the load resistance variation of 2:1
which _you_ used, but not with the constant load resistance which _I_
used in my example.

For example: if the mains are 240V, the plug is good for 10 amps, and
the load is 2400 watts, then the load's resistance will be 24 ohms.

Plugging that 24 ohms into a 120V source would result in its
dissipating 600 watts, which is 1/4 the power it would have dissipated
were it connected across 240V mains.


You said this:


A blade made of brass with a width of 1/4", a thickness of 1/16" and a
length of about an inch is hardly flimsy, and serves us well when we
opt to go to 240V and eke out four times the power available from the
mains without changing plugs.

which is just wrong.

---
Right you are!

Changing just one word, though, would make it right.

Care to guess which one?

Easy. Change "four" to "two."
Click to expand...
---
Wrong, but understandable since what I meant was "adding one word."

Mea culpa.

Wanna try again?

--
JF
 
On Sun, 20 May 2012 16:49:50 -0500, John Fields
<jfields@austininstruments.com> wrote:

On Sun, 20 May 2012 09:18:07 -0700, John Larkin
jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

On Sun, 20 May 2012 01:30:51 -0500, John Fields
jfields@austininstruments.com> wrote:

On Sat, 19 May 2012 14:26:57 -0700, John Larkin
jjSNIPlarkin@highTHISlandtechnology.com> wrote:

On Sat, 19 May 2012 15:08:30 -0500, John Fields
jfields@austininstruments.com> wrote:

On Sat, 19 May 2012 09:49:10 -0700, John Larkin
jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

On Fri, 18 May 2012 09:54:03 -0500, John Fields
jfields@austininstruments.com> wrote:

On Thu, 17 May 2012 17:11:41 -0700, John Larkin
jlarkin@highlandtechnology.com> wrote:

On Thu, 17 May 2012 16:52:33 +0000 (UTC), Cydrome Leader
presence@MUNGEpanix.com> wrote:

John Fields <jfields@austininstruments.com> wrote:
On Tue, 15 May 2012 21:42:24 +0100, "Ian Field"
gangprobing.alien@ntlworld.com> wrote:


"Phil Hobbs" <pcdhSpamMeSenseless@electrooptical.net> wrote in message
news:4FB2BA60.381879AC@electrooptical.net...
news@jecarter.us wrote:

On Tue, 15 May 2012 11:22:21 -0700 (PDT), George Herold
gherold@teachspin.com> wrote:


Why do US 120 VAC power plugs have holes in the end of the blades?

George H.

To allow you to put the shackle of a small lock through the blade to
ensure the item can't be plugged in for use?

I suspect it's to mate with a small boss on the blades of the socket, to
make it less likely to jiggle loose. The British solved that problem by
the traditional method of "add mass until nothing breaks."


I always marvelled at how the Yanks got away with such flimsy plugs when
half the voltage means twice the current for the same load power.

---
A blade made of brass with a width of 1/4", a thickness of 1/16" and a
length of about an inch is hardly flimsy, and serves us well when we
opt to go to 240V and eke out four times the power available from the
mains without changing plugs.

is this some sort of metric math?


What's even more "shocking" than his math

---
Connect a 120 ohm resistor across 120V mains. How much power will it
dissipate? Call that P1.

Connect a 120 ohm resistor across 240V mains. How much power will it
dissipate? Call that P2.

Divide P2 by P1. What do you get?

Technically, the wrong answer.

---
What, you don't know how to divide???
---

---

is that he uses the same plug for 120 and for 240.

---
You've never done that?

NO!

---
I do it all the time Mr. Gutless!

That is, I have a 0 -> 140V 1.4kVA VARIAC connected to the paralleled
primaries of a 3kVA isolation transformer with the secondaries wired
in series, so I can get 0 -> 560 VRMS out of the transformer.

Its primaries and secondaries are wired to a terminal block with
ring-tongue terminal jumpers on the user side so I can change the
connections to the transformer as required.

In addition, the output of the transformer is fused and connected to
about 18" of zip cord terminated with a polarized two-terminal US
style AC receptacle.

Into that receptacle normally goes about an 8 foot long suicide cord
with copper mini-alligator clips (Mueller 30C) and vinyl boots
(Mueller BU-32-2) on the business end.

Want a picture?
---

If the plug is good for 10 amps, you can power a 1200 watt load from
120 volts. That same plug can power a 2400 watt load from 240 volts.

2:1 is the available-power ratio that you can "eke out" , not 4:1.

---
Sorry, Charlie, but you're cheating again by moving the goalposts.

2:1 is what's available with the load resistance variation of 2:1
which _you_ used, but not with the constant load resistance which _I_
used in my example.

For example: if the mains are 240V, the plug is good for 10 amps, and
the load is 2400 watts, then the load's resistance will be 24 ohms.

Plugging that 24 ohms into a 120V source would result in its
dissipating 600 watts, which is 1/4 the power it would have dissipated
were it connected across 240V mains.


You said this:


A blade made of brass with a width of 1/4", a thickness of 1/16" and a
length of about an inch is hardly flimsy, and serves us well when we
opt to go to 240V and eke out four times the power available from the
mains without changing plugs.

which is just wrong.

---
Right you are!

Changing just one word, though, would make it right.

Care to guess which one?

Easy. Change "four" to "two."

---
Wrong, but understandable since what I meant was "adding one word."

Mea culpa.

Wanna try again?
Click to expand...
No. What you said was wrong and stupid, applying "Ohm's Law" without
thinking, as amateurs often do.

Weasel it out yourself.


--

John Larkin Highland Technology Inc
www.highlandtechnology.com jlarkin at highlandtechnology dot com

Precision electronic instrumentation
Picosecond-resolution Digital Delay and Pulse generators
Custom timing and laser controllers
Photonics and fiberoptic TTL data links
VME analog, thermocouple, LVDT, synchro, tachometer
Multichannel arbitrary waveform generators
 
On Sun, 20 May 2012 16:57:42 -0400, "krw@att.bizzzzzzzzzzzz"
<krw@att.bizzzzzzzzzzzz> wrote:

On Sun, 20 May 2012 19:53:39 +0100, "Ian Field"
gangprobing.alien@ntlworld.com> wrote:


"Cydrome Leader" <presence@MUNGEpanix.com> wrote in message
news:jpbdhv$ngg$3@reader1.panix.com...
John Fields <jfields@austininstruments.com> wrote:
On Thu, 17 May 2012 16:52:33 +0000 (UTC), Cydrome Leader
presence@MUNGEpanix.com> wrote:

John Fields <jfields@austininstruments.com> wrote:
On Tue, 15 May 2012 21:42:24 +0100, "Ian Field"
gangprobing.alien@ntlworld.com> wrote:


"Phil Hobbs" <pcdhSpamMeSenseless@electrooptical.net> wrote in message
news:4FB2BA60.381879AC@electrooptical.net...
news@jecarter.us wrote:

On Tue, 15 May 2012 11:22:21 -0700 (PDT), George Herold
gherold@teachspin.com> wrote:


Why do US 120 VAC power plugs have holes in the end of the blades?

George H.

To allow you to put the shackle of a small lock through the blade to
ensure the item can't be plugged in for use?

I suspect it's to mate with a small boss on the blades of the socket,
to
make it less likely to jiggle loose. The British solved that problem
by
the traditional method of "add mass until nothing breaks."


I always marvelled at how the Yanks got away with such flimsy plugs
when
half the voltage means twice the current for the same load power.

---
A blade made of brass with a width of 1/4", a thickness of 1/16" and a
length of about an inch is hardly flimsy, and serves us well when we
opt to go to 240V and eke out four times the power available from the
mains without changing plugs.

is this some sort of metric math?

---
Well, we're not dealing with feet and inches, so you figure it out:

120V mains, 120 ohm load, 120 watts

240V mains, 120 ohm load, 480 watts

480
----- = 4
120


so you're telling me if an outlet is rated and fused to supply say 15 amps
at 120 volts, that if I double the voltage across it's supply it can now
safely handle 30 amps at 240?

What sort of jenky bullshit "instruments" to you make?


He's an escaped loony who likes to pretend he's "professional people".

At least he's not an engineer.
Click to expand...
Yeah, we can be spared that embarassment.


--

John Larkin Highland Technology Inc
www.highlandtechnology.com jlarkin at highlandtechnology dot com

Precision electronic instrumentation
Picosecond-resolution Digital Delay and Pulse generators
Custom timing and laser controllers
Photonics and fiberoptic TTL data links
VME analog, thermocouple, LVDT, synchro, tachometer
Multichannel arbitrary waveform generators
 
On Sun, 20 May 2012 18:35:43 +0000 (UTC), Cydrome Leader
<presence@MUNGEpanix.com> wrote:

John Fields <jfields@austininstruments.com> wrote:
On Thu, 17 May 2012 16:52:33 +0000 (UTC), Cydrome Leader
presence@MUNGEpanix.com> wrote:

John Fields <jfields@austininstruments.com> wrote:
On Tue, 15 May 2012 21:42:24 +0100, "Ian Field"
gangprobing.alien@ntlworld.com> wrote:


"Phil Hobbs" <pcdhSpamMeSenseless@electrooptical.net> wrote in message
news:4FB2BA60.381879AC@electrooptical.net...
news@jecarter.us wrote:

On Tue, 15 May 2012 11:22:21 -0700 (PDT), George Herold
gherold@teachspin.com> wrote:


Why do US 120 VAC power plugs have holes in the end of the blades?

George H.

To allow you to put the shackle of a small lock through the blade to
ensure the item can't be plugged in for use?

I suspect it's to mate with a small boss on the blades of the socket, to
make it less likely to jiggle loose. The British solved that problem by
the traditional method of "add mass until nothing breaks."


I always marvelled at how the Yanks got away with such flimsy plugs when
half the voltage means twice the current for the same load power.

---
A blade made of brass with a width of 1/4", a thickness of 1/16" and a
length of about an inch is hardly flimsy, and serves us well when we
opt to go to 240V and eke out four times the power available from the
mains without changing plugs.

is this some sort of metric math?

---
Well, we're not dealing with feet and inches, so you figure it out:

120V mains, 120 ohm load, 120 watts

240V mains, 120 ohm load, 480 watts

480
----- = 4
120


so you're telling me if an outlet is rated and fused to supply say 15 amps
at 120 volts, that if I double the voltage across it's supply it can now
safely handle 30 amps at 240?
Click to expand...
---
Not at all.

What I'm saying is that if you have an outlet which can handle 15 amps
with 240V across it, then a 16 ohm load will dissipate 3600 watts

Connect that same 16 ohm load across the same socket with 120V across
it and the dissipation drops to 900 watts, ergo

3600W
------ = 4
900W
What sort of jenky bullshit "instruments" to you make?
Click to expand...
---
"jenky"?

"to you make"

What do you mean?

--
JF
 
On Sun, 20 May 2012 19:53:39 +0100, "Ian Field"
<gangprobing.alien@ntlworld.com> wrote:

"Cydrome Leader" <presence@MUNGEpanix.com> wrote in message
news:jpbdhv$ngg$3@reader1.panix.com...
John Fields <jfields@austininstruments.com> wrote:
On Thu, 17 May 2012 16:52:33 +0000 (UTC), Cydrome Leader
presence@MUNGEpanix.com> wrote:

John Fields <jfields@austininstruments.com> wrote:
On Tue, 15 May 2012 21:42:24 +0100, "Ian Field"
gangprobing.alien@ntlworld.com> wrote:


"Phil Hobbs" <pcdhSpamMeSenseless@electrooptical.net> wrote in message
news:4FB2BA60.381879AC@electrooptical.net...
news@jecarter.us wrote:

On Tue, 15 May 2012 11:22:21 -0700 (PDT), George Herold
gherold@teachspin.com> wrote:


Why do US 120 VAC power plugs have holes in the end of the blades?

George H.

To allow you to put the shackle of a small lock through the blade to
ensure the item can't be plugged in for use?

I suspect it's to mate with a small boss on the blades of the socket,
to
make it less likely to jiggle loose. The British solved that problem
by
the traditional method of "add mass until nothing breaks."


I always marvelled at how the Yanks got away with such flimsy plugs
when
half the voltage means twice the current for the same load power.

---
A blade made of brass with a width of 1/4", a thickness of 1/16" and a
length of about an inch is hardly flimsy, and serves us well when we
opt to go to 240V and eke out four times the power available from the
mains without changing plugs.

is this some sort of metric math?

---
Well, we're not dealing with feet and inches, so you figure it out:

120V mains, 120 ohm load, 120 watts

240V mains, 120 ohm load, 480 watts

480
----- = 4
120


so you're telling me if an outlet is rated and fused to supply say 15 amps
at 120 volts, that if I double the voltage across it's supply it can now
safely handle 30 amps at 240?

What sort of jenky bullshit "instruments" to you make?


He's an escaped loony who likes to pretend he's "professional people".
Click to expand...
---
Interesting...

you have very little technical expertise, and yet you chose to rail
against us who do.

To what end?

--
JF
 
On Sun, 20 May 2012 18:14:44 -0500, John Fields
<jfields@austininstruments.com> wrote:

On Sun, 20 May 2012 19:53:39 +0100, "Ian Field"
gangprobing.alien@ntlworld.com> wrote:


"Cydrome Leader" <presence@MUNGEpanix.com> wrote in message
news:jpbdhv$ngg$3@reader1.panix.com...
John Fields <jfields@austininstruments.com> wrote:
On Thu, 17 May 2012 16:52:33 +0000 (UTC), Cydrome Leader
presence@MUNGEpanix.com> wrote:

John Fields <jfields@austininstruments.com> wrote:
On Tue, 15 May 2012 21:42:24 +0100, "Ian Field"
gangprobing.alien@ntlworld.com> wrote:


"Phil Hobbs" <pcdhSpamMeSenseless@electrooptical.net> wrote in message
news:4FB2BA60.381879AC@electrooptical.net...
news@jecarter.us wrote:

On Tue, 15 May 2012 11:22:21 -0700 (PDT), George Herold
gherold@teachspin.com> wrote:


Why do US 120 VAC power plugs have holes in the end of the blades?

George H.

To allow you to put the shackle of a small lock through the blade to
ensure the item can't be plugged in for use?

I suspect it's to mate with a small boss on the blades of the socket,
to
make it less likely to jiggle loose. The British solved that problem
by
the traditional method of "add mass until nothing breaks."


I always marvelled at how the Yanks got away with such flimsy plugs
when
half the voltage means twice the current for the same load power.

---
A blade made of brass with a width of 1/4", a thickness of 1/16" and a
length of about an inch is hardly flimsy, and serves us well when we
opt to go to 240V and eke out four times the power available from the
mains without changing plugs.

is this some sort of metric math?

---
Well, we're not dealing with feet and inches, so you figure it out:

120V mains, 120 ohm load, 120 watts

240V mains, 120 ohm load, 480 watts

480
----- = 4
120


so you're telling me if an outlet is rated and fused to supply say 15 amps
at 120 volts, that if I double the voltage across it's supply it can now
safely handle 30 amps at 240?

What sort of jenky bullshit "instruments" to you make?


He's an escaped loony who likes to pretend he's "professional people".

---
Interesting...

you have very little technical expertise, and yet you chose to rail
against us who do.
Click to expand...
Wait a second here. YOU GOT IT WRONG. HE IS RIGHT.

So, where is your "technical expertise" ?
 
On Sun, 20 May 2012 17:39:37 -0500, John Fields
<jfields@austininstruments.com> wrote:

On Sun, 20 May 2012 18:35:43 +0000 (UTC), Cydrome Leader
presence@MUNGEpanix.com> wrote:

John Fields <jfields@austininstruments.com> wrote:
On Thu, 17 May 2012 16:52:33 +0000 (UTC), Cydrome Leader
presence@MUNGEpanix.com> wrote:

John Fields <jfields@austininstruments.com> wrote:
On Tue, 15 May 2012 21:42:24 +0100, "Ian Field"
gangprobing.alien@ntlworld.com> wrote:


"Phil Hobbs" <pcdhSpamMeSenseless@electrooptical.net> wrote in message
news:4FB2BA60.381879AC@electrooptical.net...
news@jecarter.us wrote:

On Tue, 15 May 2012 11:22:21 -0700 (PDT), George Herold
gherold@teachspin.com> wrote:


Why do US 120 VAC power plugs have holes in the end of the blades?

George H.

To allow you to put the shackle of a small lock through the blade to
ensure the item can't be plugged in for use?

I suspect it's to mate with a small boss on the blades of the socket, to
make it less likely to jiggle loose. The British solved that problem by
the traditional method of "add mass until nothing breaks."


I always marvelled at how the Yanks got away with such flimsy plugs when
half the voltage means twice the current for the same load power.

---
A blade made of brass with a width of 1/4", a thickness of 1/16" and a
length of about an inch is hardly flimsy, and serves us well when we
opt to go to 240V and eke out four times the power available from the
mains without changing plugs.

is this some sort of metric math?

---
Well, we're not dealing with feet and inches, so you figure it out:

120V mains, 120 ohm load, 120 watts

240V mains, 120 ohm load, 480 watts

480
----- = 4
120


so you're telling me if an outlet is rated and fused to supply say 15 amps
at 120 volts, that if I double the voltage across it's supply it can now
safely handle 30 amps at 240?

---
Not at all.

What I'm saying is that if you have an outlet which can handle 15 amps
with 240V across it, then a 16 ohm load will dissipate 3600 watts

Connect that same 16 ohm load across the same socket with 120V across
it and the dissipation drops to 900 watts, ergo

3600W
------ = 4
900W
Click to expand...

But the 15 amp outlet could *handle* 1800 watts at 120 volts, which is
the issue here.

Weasel.
 
On Sun, 20 May 2012 17:39:37 -0500, John Fields
<jfields@austininstruments.com> wrote:

On Sun, 20 May 2012 18:35:43 +0000 (UTC), Cydrome Leader
presence@MUNGEpanix.com> wrote:

John Fields <jfields@austininstruments.com> wrote:
On Thu, 17 May 2012 16:52:33 +0000 (UTC), Cydrome Leader
presence@MUNGEpanix.com> wrote:

John Fields <jfields@austininstruments.com> wrote:
On Tue, 15 May 2012 21:42:24 +0100, "Ian Field"
gangprobing.alien@ntlworld.com> wrote:


"Phil Hobbs" <pcdhSpamMeSenseless@electrooptical.net> wrote in message
news:4FB2BA60.381879AC@electrooptical.net...
news@jecarter.us wrote:

On Tue, 15 May 2012 11:22:21 -0700 (PDT), George Herold
gherold@teachspin.com> wrote:


Why do US 120 VAC power plugs have holes in the end of the blades?

George H.

To allow you to put the shackle of a small lock through the blade to
ensure the item can't be plugged in for use?

I suspect it's to mate with a small boss on the blades of the socket, to
make it less likely to jiggle loose. The British solved that problem by
the traditional method of "add mass until nothing breaks."


I always marvelled at how the Yanks got away with such flimsy plugs when
half the voltage means twice the current for the same load power.

---
A blade made of brass with a width of 1/4", a thickness of 1/16" and a
length of about an inch is hardly flimsy, and serves us well when we
opt to go to 240V and eke out four times the power available from the
mains without changing plugs.

is this some sort of metric math?

---
Well, we're not dealing with feet and inches, so you figure it out:

120V mains, 120 ohm load, 120 watts

240V mains, 120 ohm load, 480 watts

480
----- = 4
120


so you're telling me if an outlet is rated and fused to supply say 15 amps
at 120 volts, that if I double the voltage across it's supply it can now
safely handle 30 amps at 240?

---
Not at all.

What I'm saying is that if you have an outlet which can handle 15 amps
with 240V across it, then a 16 ohm load will dissipate 3600 watts

Connect that same 16 ohm load across the same socket with 120V across
it and the dissipation drops to 900 watts, ergo

3600W
------ = 4
900W

What sort of jenky bullshit "instruments" to you make?

---
"jenky"?

"to you make"

What do you mean?
Click to expand...
I'll attempt to interpret what he said into cluckese, "the outlet and the
circuit is only rated for 15A, moron". Now apologize for being a fathead.
 
Ian Field wrote:
"Michael A. Terrell" <mike.terrell@earthlink.net> wrote in message
news:dqGdnfXFl41TAyrSnZ2dnUVZ_q6dnZ2d@earthlink.com...

Roger wrote:

fungus wrote:

They also thought to put on/off switches
on all the wall sockets - incredibly useful.

No, the Australian-New Zealand system is the best. The wall sockets
are all switched.


Who needs that? Is everything you plug in so low grade that you have
to turn off the outlet between uses? All I see is that it lowers the
reliability of every outlet by adding more parts. Rube Goldberg would
be proud of those outlets.

The reliabilityy is pretty good - unlike the previous unswitched round pin
outlets that were a disaster that frequently didn't wait to happen!
Click to expand...

Then you went from substandard crap, to over engineered.


--
You can't have a sense of humor, if you have no sense.
 
On Sun, 20 May 2012 15:13:30 -0700, John Larkin
<jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

On Sun, 20 May 2012 16:49:50 -0500, John Fields
jfields@austininstruments.com> wrote:

On Sun, 20 May 2012 09:18:07 -0700, John Larkin
jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

You said this:


A blade made of brass with a width of 1/4", a thickness of 1/16" and a
length of about an inch is hardly flimsy, and serves us well when we
opt to go to 240V and eke out four times the power available from the
mains without changing plugs.

which is just wrong.

---
Right you are!

Changing just one word, though, would make it right.

Care to guess which one?

Easy. Change "four" to "two."

---
Wrong, but understandable since what I meant was "adding one word."

Mea culpa.

Wanna try again?

No. What you said was wrong and stupid, applying "Ohm's Law" without
thinking, as amateurs often do.

Weasel it out yourself.
Click to expand...
---
Oh, my, Johnny's working himself up to a lather because he's missed
the point.

The word is 120V and it should be added before "mains".

Also, hardly wrong or stupid considering that, in the argument, if a
resistor is connected across 120V mains it'll dissipate a certain
power, while if connected across 240V mains the power dissipation will
quadruple.

Is that not correct, Mr Wizard?

--
JF
 
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