I saw something in an auto repair magazine the other day that really
intrigued me. This was a coil of some sort, (and these come in
different sizes), that you put over a rusted nut. It claims to heat
the nut to cherry red apparently by induction thereby facilitating its
removal. This would replace a torch for instance and would be a lot
safer when working around a plastic gas tank. The machine that these
probes plug into is very expensive but you can buy a set of these
different size probes for under 200.00 Is anyone familiar with this
type of equipment, and do you know if it might be possible to
construct a generic version of the machine that energizes the probes
to heat the nuts? What is actually happening here? Thanks, Lenny

klem kedidelhopper wrote:
I saw something in an auto repair magazine the other day that really
intrigued me. This was a coil of some sort, (and these come in
different sizes), that you put over a rusted nut. It claims to heat
the nut to cherry red apparently by induction thereby facilitating its
removal. This would replace a torch for instance and would be a lot
safer when working around a plastic gas tank. The machine that these
probes plug into is very expensive but you can buy a set of these
different size probes for under 200.00 Is anyone familiar with this
type of equipment, and do you know if it might be possible to
construct a generic version of the machine that energizes the probes
to heat the nuts? What is actually happening here? Thanks, Lenny

The way I misunderstand it, eddy currents inductively
induced in the target dissipate power because of resistance.

http://en.wikipedia.org/wiki/Induction_heating

http://blog.makezine.com/2008/03/25/...ction-heating/
http://hackedgadgets.com/2008/11/25/...uction-heater/
http://www.fluxeon.com/Roy1200open.html

Very nifty.

--Winston

klem kedidelhopper wrote in message
...
I saw something in an auto repair magazine the other day that really
intrigued me. This was a coil of some sort, (and these come in
different sizes), that you put over a rusted nut. It claims to heat
the nut to cherry red apparently by induction thereby facilitating its
removal. This would replace a torch for instance and would be a lot
safer when working around a plastic gas tank. The machine that these
probes plug into is very expensive but you can buy a set of these
different size probes for under 200.00 Is anyone familiar with this
type of equipment, and do you know if it might be possible to
construct a generic version of the machine that energizes the probes
to heat the nuts? What is actually happening here? Thanks, Lenny


Would it also activate getter (assuming you can get hold of caesium or
whatever it is)
in a valve/tube , should anyone try and make any ? eg
http://paillard.claude.free.fr/triodes/plantri.html
en Francais

"klem kedidelhopper" wrote in message
...
I saw something in an auto repair magazine the other day that really
intrigued me. This was a coil of some sort, (and these come in
different sizes), that you put over a rusted nut. It claims to heat
the nut to cherry red apparently by induction thereby facilitating its
removal. This would replace a torch for instance and would be a lot
safer when working around a plastic gas tank. The machine that these
probes plug into is very expensive but you can buy a set of these
different size probes for under 200.00 Is anyone familiar with this
type of equipment, and do you know if it might be possible to
construct a generic version of the machine that energizes the probes
to heat the nuts? What is actually happening here? Thanks, Lenny


Induction heating has been around a lot longer than modern semiconductor
devices - ideal for case hardening steel shafts.

On Sat, 7 Apr 2012 12:25:38 -0700 (PDT), klem kedidelhopper
wrote:

It claims to heat
the nut to cherry red apparently by induction
[snip]
Is anyone familiar with this
type of equipment, and do you know if it might be possible to
construct a generic version

As it happens, there is an instructable posted a few days ago that
describes how to build your own induction heater. It is not totally
trivial, but seems quite doable:

http://www.instructables.com/id/30-k...uction-Heater/
--
RoRo

On 4/7/2012 2:25 PM, klem kedidelhopper wrote:
I saw something in an auto repair magazine the other day that really
intrigued me. This was a coil of some sort, (and these come in
different sizes), that you put over a rusted nut. It claims to heat
the nut to cherry red apparently by induction thereby facilitating its
removal. This would replace a torch for instance and would be a lot
safer when working around a plastic gas tank. The machine that these
probes plug into is very expensive but you can buy a set of these
different size probes for under 200.00 Is anyone familiar with this
type of equipment, and do you know if it might be possible to
construct a generic version of the machine that energizes the probes
to heat the nuts? What is actually happening here? Thanks, Lenny

Take a look at some induction heaters in action in action.
Watch the wrap.

http://www.youtube.com/results?searc... .896.12.12.0.

Mikek

Just mentioning, a company called Ohio Crankshaft was a pioneer in
this a long time ago. Induction heating was used for hardening, mainly
case hardening steel. It was called the TOCCO process.

In the old days the flux wasn't all that well controlled and there was
plenty of power. The olman told me that the machine pulled 700 amps a
700 volts. This brought cranks and cams up to quenching temperature in
seconds, maybe sooner. After all 49 Kw can do that. About the flux,
when they said get everything metal out of your pockets they meant it.
One guy had a lighter on him working with the machine and got burned
really badly.

Some minor info available here : http://papers.sae.org/370166/

There is not a whole lot of info on it available on the net searching
directly for TOCCO. But then as good as it is, they screwed up a whole
lot of Chevy camshafts about 25 years ago or so. ALOT of them. I got a
buddy who actually knows how to work on those things, but there are
only so many. There doesn't need to be that many. At 49 Kw I'm sure
the process goes pretty fast. That was kinda the idea.

Anyone want to buy an induction cooktop ? I got one stashed somewhere,
just because I figured it could be dangerous.

To build the box that feeds the coils should not be all that
difficult. It does not use microwave frequencies, it's just RF. Some
switched mode power supplies run higher frequencies these days.

J

Jeff Urban wrote:

Just mentioning, a company called Ohio Crankshaft was a pioneer in
this a long time ago. Induction heating was used for hardening, mainly
case hardening steel. It was called the TOCCO process.

In the old days the flux wasn't all that well controlled and there was
plenty of power. The olman told me that the machine pulled 700 amps a
700 volts. This brought cranks and cams up to quenching temperature in
seconds, maybe sooner. After all 49 Kw can do that. About the flux,
when they said get everything metal out of your pockets they meant it.
One guy had a lighter on him working with the machine and got burned
really badly.

Some minor info available here : http://papers.sae.org/370166/

There is not a whole lot of info on it available on the net searching
directly for TOCCO. But then as good as it is, they screwed up a whole
lot of Chevy camshafts about 25 years ago or so. ALOT of them. I got a
buddy who actually knows how to work on those things, but there are
only so many. There doesn't need to be that many. At 49 Kw I'm sure
the process goes pretty fast. That was kinda the idea.

Anyone want to buy an induction cooktop ? I got one stashed somewhere,
just because I figured it could be dangerous.

To build the box that feeds the coils should not be all that
difficult. It does not use microwave frequencies, it's just RF. Some
switched mode power supplies run higher frequencies these days.

J
Well, most of them operate in the 30k..80k hz range, I guess that is a
good pick for the eddy current generations.

I just wonder how they actually did it years ago, as far as getting
that much power at that frequency ?

You can use a thyristor approach which was used for power supplies
once, it also can be used to for an induction heater.

Years ago getting the electronics for switching style of heater would
of made it impractical in many cases however, I guess if you have the
room to put such equipment then you're all set.

At work, we have one area that uses a induction heater to bond a
special wire together in a ceramic mold. The coil is actually a split
that needs to be assembled around the point where these two items come
together. The block is non-conductive but contains the conductive coil
tubing. When the block gets put back together, these tubing's get
electrically connected to each other and they have O-rings in there too.

That unit is a 10kW unit using a 60 hz square wave driving a series
resonant tank, the coil being the induction coil. There is no inverter
in there per say, but due to the high Q, ringing of the tank is used to
produce a 60 hz pulse of ~ 50 kHz of ringing on the coil. It works very
well and is semi portable.

Jamie

In the old days the flux wasn't all that well controlled, and there
was plenty of power. The olman told me that the machine pulled
700 amps at 700 volts. This brought cranks and cams up to
quenching temperature in seconds, maybe sooner. After all.
49 kW can do that.

Uh... that's 490kW -- nearly half a megawatt.

William Sommerwerck wrote:

In the old days the flux wasn't all that well controlled, and there
was plenty of power. The olman told me that the machine pulled
700 amps at 700 volts. This brought cranks and cams up to
quenching temperature in seconds, maybe sooner. After all.
49 kW can do that.


Uh... that's 490kW -- nearly half a megawatt.


ah, just enough to keep you warm in the winter, on the other side of
the building that is

Jamie

Uh... that's 490kW -- nearly half a megawatt!

Ah, just enough to keep you warm in the winter,
on the other side of the building, that is

Well, at least you know your nuts won't get cold.

On Apr 8, 2:56*pm, Jamie
t wrote:
Jeff Urban wrote:
Just mentioning, a company called Ohio Crankshaft was a pioneer in
this a long time ago. Induction heating was used for hardening, mainly
case hardening steel. It was called the TOCCO process.

In the old days the flux wasn't all that well controlled and there was
plenty of power. The olman told me that the machine pulled 700 amps a
700 volts. This brought cranks and cams up to quenching temperature in
seconds, maybe sooner. After all 49 Kw can do that. About the flux,
when they said get everything metal out of your pockets they meant it.
One guy had a lighter on him working with the machine and got burned
really badly.

Some minor info available here :http://papers.sae.org/370166/

There is not a whole lot of info on it available on the net searching
directly for TOCCO. But then as good as it is, they screwed up a whole
lot of Chevy camshafts about 25 years ago or so. ALOT of them. I got a
buddy who actually knows how to work on those things, but there are
only so many. There doesn't need to be that many. At 49 Kw I'm sure
the process goes pretty fast. That was kinda the idea.

Anyone want to buy an induction cooktop ? I got one stashed somewhere,
just because I figured it could be dangerous.

To build the box that feeds the coils should not be all that
difficult. It does not use microwave frequencies, it's just RF. Some
switched mode power supplies run higher frequencies these days.

J

Well, most of them operate in the 30k..80k hz range, I guess that is a
good pick for the eddy current generations.

* *I just wonder how they actually did it years ago, as far as getting
that much power at that frequency ?

* *You can use a thyristor approach which was used for power supplies
once, it also can be used to for an induction heater.

* *Years ago getting the electronics for switching style of heater would
of made it impractical in many cases however, I guess if you have the
room to put such equipment then you're all set.

* *At work, we have one area that uses a induction heater to bond a
special wire together in a ceramic mold. The coil is actually a split
that needs to be assembled around the point where these two items come
together. The block is non-conductive but contains the conductive coil
tubing. When the block gets put back together, these tubing's get
electrically connected to each other and they have O-rings in there too.

* *That unit is a 10kW unit using a 60 hz square wave driving a series
resonant tank, the coil being the induction coil. There is no inverter
in there per say, but due to the high Q, ringing of the tank is used to
produce a 60 hz pulse of ~ 50 kHz of ringing on the coil. It works very
well and is semi portable.

* Jamie

In 70;s Doug Schatz (then, of Applied Materials in Sunnyvale, CA)
designed and built the Pachydyne series of Induction Furnaces for sale
to companies like Bethlehem Steel. They were simple inverters: AC
mains to DC, then DC to AC, 50kHz at over 150kW. All done using 3-
phase H configuration SCR switches. Doug knew everything about how to
turn on, and how NOT to turn on, an SCR. The SCR's were those 'hockey
puck' packages that rattled if you shook them, so you'd clamp them
into the heat sink to collapse the glass package and make contact to
the SCR substrates. The wiring was 3/8 inch copper tubing with water
running through the tubes for cooling. It only took 7 turns of tubing
around a carbon graphite sink full of zinc chunks to melt the zinc
down into liquid in less than 20 minutes. You could walk up to the
liquid, stir it, add stuff, whatever. I was told that action was
impossible using a gas fired caldron. The induction furnaces were
used in controlled atmosphere to make esoteric alloys. His solid
state inverter were 85-90% efficiency and intended to replace vacuum
tube systems that were about 10% efficient! Imagine your electric
bill!

During development, there were lots of dramatic failures! Like when
no one thought about the fact that a metal washer is a shorted
transformer turn, so when they were first operating the system, the
washers got hot, burnt through bolts and mounting hardware, thus
supporting members and electronics started falling down - showers of
sparks and fire! Or, trying to debug operation, when all the unit
would do is go ZAP and burn out all 12 SCR's, which cost $100ea and
took all day to replace. From that to the final version, where the
design was so robust you could walk up to the tank with its loops of
copper pipes (wires) and drag a shorting rod over pipes, producing an
impressive shower of sparks and an accompanying crack as breakers and
shut down went off - but afterwards all you had to do was reset and
turn back on and you were up and running again.

On Apr 9, 10:21*am, Robert Macy wrote:
On Apr 8, 2:56*pm, Jamie









t wrote:
Jeff Urban wrote:
Just mentioning, a company called Ohio Crankshaft was a pioneer in
this a long time ago. Induction heating was used for hardening, mainly
case hardening steel. It was called the TOCCO process.

In the old days the flux wasn't all that well controlled and there was
plenty of power. The olman told me that the machine pulled 700 amps a
700 volts. This brought cranks and cams up to quenching temperature in
seconds, maybe sooner. After all 49 Kw can do that. About the flux,
when they said get everything metal out of your pockets they meant it..
One guy had a lighter on him working with the machine and got burned
really badly.

Some minor info available here :http://papers.sae.org/370166/

There is not a whole lot of info on it available on the net searching
directly for TOCCO. But then as good as it is, they screwed up a whole
lot of Chevy camshafts about 25 years ago or so. ALOT of them. I got a
buddy who actually knows how to work on those things, but there are
only so many. There doesn't need to be that many. At 49 Kw I'm sure
the process goes pretty fast. That was kinda the idea.

Anyone want to buy an induction cooktop ? I got one stashed somewhere,
just because I figured it could be dangerous.

To build the box that feeds the coils should not be all that
difficult. It does not use microwave frequencies, it's just RF. Some
switched mode power supplies run higher frequencies these days.

J

Well, most of them operate in the 30k..80k hz range, I guess that is a
good pick for the eddy current generations.

* *I just wonder how they actually did it years ago, as far as getting
that much power at that frequency ?

* *You can use a thyristor approach which was used for power supplies
once, it also can be used to for an induction heater.

* *Years ago getting the electronics for switching style of heater would
of made it impractical in many cases however, I guess if you have the
room to put such equipment then you're all set.

* *At work, we have one area that uses a induction heater to bond a
special wire together in a ceramic mold. The coil is actually a split
that needs to be assembled around the point where these two items come
together. The block is non-conductive but contains the conductive coil
tubing. When the block gets put back together, these tubing's get
electrically connected to each other and they have O-rings in there too..

* *That unit is a 10kW unit using a 60 hz square wave driving a series
resonant tank, the coil being the induction coil. There is no inverter
in there per say, but due to the high Q, ringing of the tank is used to
produce a 60 hz pulse of ~ 50 kHz of ringing on the coil. It works very
well and is semi portable.

* Jamie

In 70;s Doug Schatz (then, of Applied Materials in Sunnyvale, CA)
designed and built the Pachydyne series of Induction Furnaces for sale
to companies like Bethlehem Steel. They were simple inverters: AC
mains to DC, then DC to AC, 50kHz at over 150kW. *All done using 3-
phase H configuration SCR switches. Doug knew everything about how to
turn on, and how NOT to turn on, an SCR. The SCR's were those 'hockey
puck' packages that rattled if you shook them, so you'd clamp them
into the heat sink to collapse the glass package and make contact to
the SCR substrates. *The wiring was 3/8 inch copper tubing with water
running through the tubes for cooling. *It only took 7 turns of tubing
around a carbon graphite sink full of zinc chunks to melt the zinc
down into liquid in less than 20 minutes. *You could walk up to the
liquid, stir it, add stuff, whatever. I was told that action was
impossible using a gas fired caldron. *The induction furnaces were
used in controlled atmosphere to make esoteric alloys. *His solid
state inverter were 85-90% efficiency and intended to replace vacuum
tube systems that were about 10% efficient! *Imagine your electric
bill!

During development, there were lots of dramatic failures! *Like when
no one thought about the fact that a metal washer is a shorted
transformer turn, so when they were first operating the system, the
washers got hot, burnt through bolts and mounting hardware, thus
supporting members and electronics started falling down - showers of
sparks and fire! * Or, trying to debug operation, when all the unit
would do is go ZAP and burn out all 12 SCR's, which cost $100ea and
took all day to replace. From that to the final version, where the
design was so robust you could walk up to the tank with its loops of
copper pipes (wires) and drag a shorting rod over pipes, producing an
impressive shower of sparks and an accompanying crack as breakers and
shut down went off - but afterwards all you had to do was reset and
turn back on and you were up and running again.

I don't know if I'm going to try to build one of these things. I
should probably stick to repairing Grundig radios. What do you think
Winston? Lenny

klem kedidelhopper wrote:

(...)

I don't know if I'm going to try to build one of these things. I
should probably stick to repairing Grundig radios. What do you think
Winston? Lenny

I would start small.

Instead of 150 KW, how about 180 W?

http://www.pocketmagic.net/?p=1731

You could get into plenty of trouble with that,
for not much money.

--Winston

klem kedidelhopper wrote in
:


I don't know if I'm going to try to build one of these things. I
should probably stick to repairing Grundig radios. What do you think
Winston? Lenny


Grundig???? switch to Philips......

Robert Macy wrote:

On Apr 8, 2:56 pm, Jamie
t wrote:

Jeff Urban wrote:

Just mentioning, a company called Ohio Crankshaft was a pioneer in
this a long time ago. Induction heating was used for hardening, mainly
case hardening steel. It was called the TOCCO process.

In the old days the flux wasn't all that well controlled and there was
plenty of power. The olman told me that the machine pulled 700 amps a
700 volts. This brought cranks and cams up to quenching temperature in
seconds, maybe sooner. After all 49 Kw can do that. About the flux,
when they said get everything metal out of your pockets they meant it.
One guy had a lighter on him working with the machine and got burned
really badly.

Some minor info available here :http://papers.sae.org/370166/

There is not a whole lot of info on it available on the net searching
directly for TOCCO. But then as good as it is, they screwed up a whole
lot of Chevy camshafts about 25 years ago or so. ALOT of them. I got a
buddy who actually knows how to work on those things, but there are
only so many. There doesn't need to be that many. At 49 Kw I'm sure
the process goes pretty fast. That was kinda the idea.

Anyone want to buy an induction cooktop ? I got one stashed somewhere,
just because I figured it could be dangerous.

To build the box that feeds the coils should not be all that
difficult. It does not use microwave frequencies, it's just RF. Some
switched mode power supplies run higher frequencies these days.

J

Well, most of them operate in the 30k..80k hz range, I guess that is a
good pick for the eddy current generations.

I just wonder how they actually did it years ago, as far as getting
that much power at that frequency ?

You can use a thyristor approach which was used for power supplies
once, it also can be used to for an induction heater.

Years ago getting the electronics for switching style of heater would
of made it impractical in many cases however, I guess if you have the
room to put such equipment then you're all set.

At work, we have one area that uses a induction heater to bond a
special wire together in a ceramic mold. The coil is actually a split
that needs to be assembled around the point where these two items come
together. The block is non-conductive but contains the conductive coil
tubing. When the block gets put back together, these tubing's get
electrically connected to each other and they have O-rings in there too.

That unit is a 10kW unit using a 60 hz square wave driving a series
resonant tank, the coil being the induction coil. There is no inverter
in there per say, but due to the high Q, ringing of the tank is used to
produce a 60 hz pulse of ~ 50 kHz of ringing on the coil. It works very
well and is semi portable.

Jamie


In 70;s Doug Schatz (then, of Applied Materials in Sunnyvale, CA)
designed and built the Pachydyne series of Induction Furnaces for sale
to companies like Bethlehem Steel. They were simple inverters: AC
mains to DC, then DC to AC, 50kHz at over 150kW. All done using 3-
phase H configuration SCR switches. Doug knew everything about how to
turn on, and how NOT to turn on, an SCR. The SCR's were those 'hockey
puck' packages that rattled if you shook them, so you'd clamp them
into the heat sink to collapse the glass package and make contact to
the SCR substrates. The wiring was 3/8 inch copper tubing with water
running through the tubes for cooling. It only took 7 turns of tubing
around a carbon graphite sink full of zinc chunks to melt the zinc
down into liquid in less than 20 minutes. You could walk up to the
liquid, stir it, add stuff, whatever. I was told that action was
impossible using a gas fired caldron. The induction furnaces were
used in controlled atmosphere to make esoteric alloys. His solid
state inverter were 85-90% efficiency and intended to replace vacuum
tube systems that were about 10% efficient! Imagine your electric
bill!

During development, there were lots of dramatic failures! Like when
no one thought about the fact that a metal washer is a shorted
transformer turn, so when they were first operating the system, the
washers got hot, burnt through bolts and mounting hardware, thus
supporting members and electronics started falling down - showers of
sparks and fire! Or, trying to debug operation, when all the unit
would do is go ZAP and burn out all 12 SCR's, which cost $100ea and
took all day to replace. From that to the final version, where the
design was so robust you could walk up to the tank with its loops of
copper pipes (wires) and drag a shorting rod over pipes, producing an
impressive shower of sparks and an accompanying crack as breakers and
shut down went off - but afterwards all you had to do was reset and
turn back on and you were up and running again.

Interesting:

We have in our inventory a whole case of hockey puck SCR's rated for
1000 Volts at 2500 amps. We really are getting to the point where there
may not be any use for them. I think I may suggest to Ebay them or what
ever.

We no longer have the few huge motors that required those in drives
that require a separate feed from the switch gear just to operate them.

We have only one 1800 HP motor left operating.

Jamie

On Apr 9, 6:46*pm, Jamie
t wrote:
Robert Macy wrote:
On Apr 8, 2:56 pm, Jamie
t wrote:

Jeff Urban wrote:

Just mentioning, a company called Ohio Crankshaft was a pioneer in
this a long time ago. Induction heating was used for hardening, mainly
case hardening steel. It was called the TOCCO process.

In the old days the flux wasn't all that well controlled and there was
plenty of power. The olman told me that the machine pulled 700 amps a
700 volts. This brought cranks and cams up to quenching temperature in
seconds, maybe sooner. After all 49 Kw can do that. About the flux,
when they said get everything metal out of your pockets they meant it.
One guy had a lighter on him working with the machine and got burned
really badly.

Some minor info available here :http://papers.sae.org/370166/

There is not a whole lot of info on it available on the net searching
directly for TOCCO. But then as good as it is, they screwed up a whole
lot of Chevy camshafts about 25 years ago or so. ALOT of them. I got a
buddy who actually knows how to work on those things, but there are
only so many. There doesn't need to be that many. At 49 Kw I'm sure
the process goes pretty fast. That was kinda the idea.

Anyone want to buy an induction cooktop ? I got one stashed somewhere,
just because I figured it could be dangerous.

To build the box that feeds the coils should not be all that
difficult. It does not use microwave frequencies, it's just RF. Some
switched mode power supplies run higher frequencies these days.

J

Well, most of them operate in the 30k..80k hz range, I guess that is a
good pick for the eddy current generations.

* I just wonder how they actually did it years ago, as far as getting
that much power at that frequency ?

* You can use a thyristor approach which was used for power supplies
once, it also can be used to for an induction heater.

* Years ago getting the electronics for switching style of heater would
of made it impractical in many cases however, I guess if you have the
room to put such equipment then you're all set.

* At work, we have one area that uses a induction heater to bond a
special wire together in a ceramic mold. The coil is actually a split
that needs to be assembled around the point where these two items come
together. The block is non-conductive but contains the conductive coil
tubing. When the block gets put back together, these tubing's get
electrically connected to each other and they have O-rings in there too..

* That unit is a 10kW unit using a 60 hz square wave driving a series
resonant tank, the coil being the induction coil. There is no inverter
in there per say, but due to the high Q, ringing of the tank is used to
produce a 60 hz pulse of ~ 50 kHz of ringing on the coil. It works very
well and is semi portable.

*Jamie

In 70;s Doug Schatz (then, of Applied Materials in Sunnyvale, CA)
designed and built the Pachydyne series of Induction Furnaces for sale
to companies like Bethlehem Steel. They were simple inverters: AC
mains to DC, then DC to AC, 50kHz at over 150kW. *All done using 3-
phase H configuration SCR switches. Doug knew everything about how to
turn on, and how NOT to turn on, an SCR. The SCR's were those 'hockey
puck' packages that rattled if you shook them, so you'd clamp them
into the heat sink to collapse the glass package and make contact to
the SCR substrates. *The wiring was 3/8 inch copper tubing with water
running through the tubes for cooling. *It only took 7 turns of tubing
around a carbon graphite sink full of zinc chunks to melt the zinc
down into liquid in less than 20 minutes. *You could walk up to the
liquid, stir it, add stuff, whatever. I was told that action was
impossible using a gas fired caldron. *The induction furnaces were
used in controlled atmosphere to make esoteric alloys. *His solid
state inverter were 85-90% efficiency and intended to replace vacuum
tube systems that were about 10% efficient! *Imagine your electric
bill!

During development, there were lots of dramatic failures! *Like when
no one thought about the fact that a metal washer is a shorted
transformer turn, so when they were first operating the system, the
washers got hot, burnt through bolts and mounting hardware, thus
supporting members and electronics started falling down - showers of
sparks and fire! * Or, trying to debug operation, when all the unit
would do is go ZAP and burn out all 12 SCR's, which cost $100ea and
took all day to replace. From that to the final version, where the
design was so robust you could walk up to the tank with its loops of
copper pipes (wires) and drag a shorting rod over pipes, producing an
impressive shower of sparks and an accompanying crack as breakers and
shut down went off - but afterwards all you had to do was reset and
turn back on and you were up and running again.

* Interesting:

* *We have in our inventory a whole case of hockey puck SCR's rated for
* 1000 Volts at 2500 amps. We really are getting to the point where there
may not be any use for them. I think I may suggest to Ebay them or what
ever.

We no longer have the few huge motors that required those in drives
that require a separate feed from the switch gear just to operate them.

* *We have only one 1800 HP motor left operating.

* Jamie

Thanks for posting the site for the demo Winston. I got intrigued with
this thing after we replaced the leaf springs in my wife's car. The
nuts were all naturally good sized and all were frozen. The one near
the plastic gas tank couldn't be heated with the torch and had to be
cut with a Sawzall. It was a very awkward procedure. A few days later
I saw the ad for this induction tool, (about 1000.00) with coils, etc.
Seeing the paper clip heated is interesting but it sure isn't a 5/8
shackle nut. It really puts into perspective the power required to do
this sort of thing. Lenny

klem kedidelhopper wrote:

(...)

Thanks for posting the site for the demo Winston. I got intrigued with
this thing after we replaced the leaf springs in my wife's car. The
nuts were all naturally good sized and all were frozen. The one near
the plastic gas tank couldn't be heated with the torch and had to be
cut with a Sawzall. It was a very awkward procedure. A few days later
I saw the ad for this induction tool, (about 1000.00) with coils, etc.
Seeing the paper clip heated is interesting but it sure isn't a 5/8
shackle nut. It really puts into perspective the power required to do
this sort of thing. Lenny

You will see many YouTube and internet articles
about induction heating.

There is this Extremely Nifty chip called the
IRS2153.
http://www.irf.com/product-info/data...a/irs2153d.pdf

Add two NMOSFETS and a few ancillary components
and you get the basis of a very competent
mini induction heater.

Please keep us in the loop!

--Winston