get some compression lugs.

On Thu, 20 Jan 2005 17:29:04 -0600, "Tim Williams"
wrote:

===For the welder rectifier I'm assembling, I need some filtering (so I hear).
===Since I have some #0 AWG aluminum wire on hand I'm going to wind it around
===some MOT cores. I already made one (barely managing to squeeze ten turns on
===it, there's space for two more but the wire is too tough!), with about 1/16"
===cardboard shim and welding the core back together (MOTs are normally welded,
===I don't see anything wrong here).
===
===My question is, what's the best way to hook up the wire to the rest of the
===system? The welder's power transformer is wound with aluminum wire and just
===clamped on the output terminals, so I'm guessing a washer and bolt will do.
===But this is 7 strand, not solid... I might be able to do it, or it might
===squish apart. I suppose I could drill a hole in a block and use a clamp
===screw to hold it in place.
===
===Tim


REMEMBER: "This is worth repeating for benefit of al newbies!
Jo Ann asked Dr. Sooooooooooooooooolow to remind people that while she has retired from selling GF (and sold
the business to Ken Fischer http://dandyorandas.com/) she has NOT retired from
helping people with sick GF and koi FOR FREE. 251-649-4790 phoning is best for
diagnosis. but, can try email put "help sick fish" in subject. Get your fish at Dandy Orandas
Dandy Orandas Dandy Orandas........you guys got that DANDY ORANDAS

"Tim Williams" wrote in message
...
| For the welder rectifier I'm assembling, I need some filtering (so I
hear).
| Since I have some #0 AWG aluminum wire on hand I'm going to wind it around
| some MOT cores. I already made one (barely managing to squeeze ten turns
on
| it, there's space for two more but the wire is too tough!), with about
1/16"
| cardboard shim and welding the core back together (MOTs are normally
welded,
| I don't see anything wrong here).
|
| My question is, what's the best way to hook up the wire to the rest of the
| system? The welder's power transformer is wound with aluminum wire and
just
| clamped on the output terminals, so I'm guessing a washer and bolt will
do.
| But this is 7 strand, not solid... I might be able to do it, or it might
| squish apart. I suppose I could drill a hole in a block and use a clamp
| screw to hold it in place.
|
| Tim

Tim, the aluminum wiring has an issue that it is most critical that you
understand. When aluminum gets hot, it expands more than copper. So much
so that after a connection has been made, used to warm, then cooled, it will
get loose because the aluminum flows out of the connection. This poor
connection now creates heat due to the resistance, which starts it all over
again. Eventually a fire happens. The NEC is very concerned about the
history of this item, and has specific rules that you can't get away with
skipping.
Use connections that have "AL-CU" stamped on it and no others for that
connection. It is wise to buy a bit of antioxidizing gel, like NoAlox or
similar, and fill the connection before you assemble it with this gel. It
keeps the dissimilar corrosion away, which makes the fire issue crop up
again. Hey, it isn't inside the walls of your house, but nonetheless I
don't think you like any unnecessary action going on, even more so in a high
current connection like a welder.

"Tim Williams" wrote in message
...
"Grady" wrote in message
news:bFYHd.17$G31.1@okepread05...
Go to your local electrical distributor and check for split bolts, or
sometimes called kearnies..

Split bolt here

http://ecatalog.fciconnect.com/fci/d...KSU17a&FAM=107

Yeah, I was thinking something like that. I doubt they have those at Ace
either though. :^)


Got a hacksaw? Make your own...

Tim, the aluminum wiring has an issue that it is most critical that you
understand. When aluminum gets hot, it expands more than copper. So much
so that after a connection has been made, used to warm, then cooled, it will
get loose because the aluminum flows out of the connection. This poor
connection now creates heat due to the resistance, which starts it all over
again. Eventually a fire happens. The NEC is very concerned about the
history of this item, and has specific rules that you can't get away with
skipping.
Use connections that have "AL-CU" stamped on it and no others for that
connection. It is wise to buy a bit of antioxidizing gel, like NoAlox or
similar, and fill the connection before you assemble it with this gel. It
keeps the dissimilar corrosion away, which makes the fire issue crop up
again. Hey, it isn't inside the walls of your house, but nonetheless I
don't think you like any unnecessary action going on, even more so in a high
current connection like a welder.








Its in my house. Apparantly , in the early 70's the bldg folks here in Arizona
got real stupid(or , more likely, had their pockets lined)and they allowed
aluminum wiring in many housing developments , including mine. So far, in the
last 5 years that I have been here, houses go up in flames about 1 per year. I
oxguarded all my outlets but I have still; had three produce smoke and the one
on my patio only works in the rain. I also eat light bulbs like nothing you
have ever seen.Even the miser type bulbs. What bs. Thanks Az. Heed any warnings
folks give about aluminum wiring. It sucks and is probably more dangerous than
terrorists on a plane.
MLM

Aluminum wiring inside a house where you have a multitude of terminations is
exactly that and illegal now. However, it is still used quite frequently all
over the country. Alot of primary high voltage cable, and URD and USE cables
are aluminum. But, they are typically on terminated on fairly long runs and
outdoors.


"JohnQ.Public" wrote in message
...
Tim, the aluminum wiring has an issue that it is most critical that
you
understand. When aluminum gets hot, it expands more than copper. So much
so that after a connection has been made, used to warm, then cooled, it
will
get loose because the aluminum flows out of the connection. This poor
connection now creates heat due to the resistance, which starts it all
over
again. Eventually a fire happens. The NEC is very concerned about the
history of this item, and has specific rules that you can't get away with
skipping.
Use connections that have "AL-CU" stamped on it and no others for that
connection. It is wise to buy a bit of antioxidizing gel, like NoAlox or
similar, and fill the connection before you assemble it with this gel. It
keeps the dissimilar corrosion away, which makes the fire issue crop up
again. Hey, it isn't inside the walls of your house, but nonetheless I
don't think you like any unnecessary action going on, even more so in a
high
current connection like a welder.








Its in my house. Apparantly , in the early 70's the bldg folks here in
Arizona
got real stupid(or , more likely, had their pockets lined)and they allowed
aluminum wiring in many housing developments , including mine. So far, in
the
last 5 years that I have been here, houses go up in flames about 1 per
year. I
oxguarded all my outlets but I have still; had three produce smoke and
the one
on my patio only works in the rain. I also eat light bulbs like nothing
you
have ever seen.Even the miser type bulbs. What bs. Thanks Az. Heed any
warnings
folks give about aluminum wiring. It sucks and is probably more dangerous
than
terrorists on a plane.
MLM

In article , says...
"Grady" wrote in message news:bFYHd.17$G31.1@okepread05...
Go to your local electrical distributor and check for split bolts, or
sometimes called kearnies..

Split bolt here

http://ecatalog.fciconnect.com/fci/d...KSU17a&FAM=107

Yeah, I was thinking something like that. I doubt they have those at Ace
either though. :^)


I think you might be surprised. If Ace doesn't have them, Home Depot
probably will.

I did some work for Burndy about 15 years ago and worked on a concept
for new automation for coining the body of those split bolts out of
copper rod.

Ned Simmons

On Thu, 20 Jan 2005 17:29:04 -0600, "Tim Williams"
wrote:

For the welder rectifier I'm assembling, I need some filtering (so I hear).
Since I have some #0 AWG aluminum wire on hand I'm going to wind it around
some MOT cores. I already made one (barely managing to squeeze ten turns on
it, there's space for two more but the wire is too tough!), with about 1/16"
cardboard shim and welding the core back together (MOTs are normally welded,
I don't see anything wrong here).

My question is, what's the best way to hook up the wire to the rest of the
system? The welder's power transformer is wound with aluminum wire and just
clamped on the output terminals, so I'm guessing a washer and bolt will do.
But this is 7 strand, not solid... I might be able to do it, or it might
squish apart. I suppose I could drill a hole in a block and use a clamp
screw to hold it in place.

Tim

What does MOT mean?

On Thu, 20 Jan 2005 17:29:04 -0600, "Tim Williams"
wrote:

For the welder rectifier I'm assembling, I need some filtering (so I hear).
Since I have some #0 AWG aluminum wire on hand I'm going to wind it around
some MOT cores. I already made one (barely managing to squeeze ten turns on
it, there's space for two more but the wire is too tough!), with about 1/16"
cardboard shim and welding the core back together (MOTs are normally welded,
I don't see anything wrong here).

If this is on the DC side, don't weld them back together. You need an
air gap or you'll saturate the iron.

Thin, soft aluminum or copper strip (with paper to insulate between
turns) is a lot easier to wind than #0 aluminum wire.

Don Foreman wrote:
On Thu, 20 Jan 2005 17:29:04 -0600, "Tim Williams"
wrote:


For the welder rectifier I'm assembling, I need some filtering (so I hear).
Since I have some #0 AWG aluminum wire on hand I'm going to wind it around
some MOT cores. I already made one (barely managing to squeeze ten turns on
it, there's space for two more but the wire is too tough!), with about 1/16"
cardboard shim and welding the core back together (MOTs are normally welded,
I don't see anything wrong here).

My question is, what's the best way to hook up the wire to the rest of the
system? The welder's power transformer is wound with aluminum wire and just
clamped on the output terminals, so I'm guessing a washer and bolt will do.
But this is 7 strand, not solid... I might be able to do it, or it might
squish apart. I suppose I could drill a hole in a block and use a clamp
screw to hold it in place.

Tim


What does MOT mean?


Clue:

1st word = "m____wave"

2nd word = "o__n"

The rest is up to you...G

Jeff

--
Jeffry Wisnia

(W1BSV + Brass Rat '57 EE)

"As long as there are final exams, there will be prayer in public
schools"

On Fri, 21 Jan 2005 04:12:38 GMT, "carl mciver"
wrote:

"Tim Williams" wrote in message
...
| For the welder rectifier I'm assembling, I need some filtering (so I
hear).
| Since I have some #0 AWG aluminum wire on hand I'm going to wind it around
| some MOT cores. I already made one (barely managing to squeeze ten turns
on
| it, there's space for two more but the wire is too tough!), with about
1/16"
| cardboard shim and welding the core back together (MOTs are normally
welded,
| I don't see anything wrong here).
|
| My question is, what's the best way to hook up the wire to the rest of the
| system? The welder's power transformer is wound with aluminum wire and
just
| clamped on the output terminals, so I'm guessing a washer and bolt will
do.
| But this is 7 strand, not solid... I might be able to do it, or it might
| squish apart. I suppose I could drill a hole in a block and use a clamp
| screw to hold it in place.
|
| Tim

Tim, the aluminum wiring has an issue that it is most critical that you
understand. When aluminum gets hot, it expands more than copper. So much
so that after a connection has been made, used to warm, then cooled, it will
get loose because the aluminum flows out of the connection. This poor
connection now creates heat due to the resistance, which starts it all over
again. Eventually a fire happens. The NEC is very concerned about the
history of this item, and has specific rules that you can't get away with
skipping.
Use connections that have "AL-CU" stamped on it and no others for that
connection.

AL-CU is no longer code legal in Canada - must be the new CO/ALR
rated devices.

In the welder, a spring loaded connection might be worth looking at -
it maintains a fixed clamping pressure regardless of temperature
expansion issues.
It is wise to buy a bit of antioxidizing gel, like NoAlox or
similar, and fill the connection before you assemble it with this gel. It
keeps the dissimilar corrosion away, which makes the fire issue crop up
again. Hey, it isn't inside the walls of your house, but nonetheless I
don't think you like any unnecessary action going on, even more so in a high
current connection like a welder.

It would be a lot better to do the winding in copper due to the problems
with aluminum in electrical work. As others have mentioned, aluminum will
eventually fail and you'll be left doing the job all over again.
Use either the same size copper wire or even copper sheet for the
application. I've found for electronic switching power supplies, that
copper tape in the right thickness works better than round wire (better
conduction and better fill of the winding) for higher power applications.

--
Why isn't there an Ozone Hole at the NORTH Pole?

On Fri, 21 Jan 2005 04:12:38 GMT, "carl mciver"
wrote:

"Tim Williams" wrote in message
...
| For the welder rectifier I'm assembling, I need some filtering (so I
hear).
| Since I have some #0 AWG aluminum wire on hand I'm going to wind it around
| some MOT cores. I already made one (barely managing to squeeze ten turns
on
| it, there's space for two more but the wire is too tough!), with about
1/16"
| cardboard shim and welding the core back together (MOTs are normally
welded,
| I don't see anything wrong here).
|
| My question is, what's the best way to hook up the wire to the rest of the
| system? The welder's power transformer is wound with aluminum wire and
just
| clamped on the output terminals, so I'm guessing a washer and bolt will
do.
| But this is 7 strand, not solid... I might be able to do it, or it might
| squish apart. I suppose I could drill a hole in a block and use a clamp
| screw to hold it in place.
|
| Tim

Tim, the aluminum wiring has an issue that it is most critical that you
understand. When aluminum gets hot, it expands more than copper. So much
so that after a connection has been made, used to warm, then cooled, it will
get loose because the aluminum flows out of the connection. This poor
connection now creates heat due to the resistance, which starts it all over
again. Eventually a fire happens. The NEC is very concerned about the
history of this item, and has specific rules that you can't get away with
skipping.
Use connections that have "AL-CU" stamped on it and no others for that
connection. It is wise to buy a bit of antioxidizing gel, like NoAlox or
similar, and fill the connection before you assemble it with this gel. It
keeps the dissimilar corrosion away, which makes the fire issue crop up
again. Hey, it isn't inside the walls of your house, but nonetheless I
don't think you like any unnecessary action going on, even more so in a high
current connection like a welder.

Below is some interesting stuff off the FAQ on Sola's site:

Pete Keillor

--------------------------------------------------------------------------------

Q. Are copper windings better than aluminum windings?

A. As with most questions of this type pertaining to transformers, a
lot depends upon the application and the individual preferences of the
person specifying the transformer. Quite often the reason cited for
specifying copper windings is copper's high electrical conductivity.

During World War II, copper became scarce and was used primarily for
the war effort. Several industries turned to aluminum as alternative
to copper because it was in good supply, was very stable price-wise
and was less expensive than copper. In the 1940's, high-power
transmission power lines were converted from copper to aluminum and
secondary power distribution networks began utilizing aluminum in the
1950's. Today, virtually all standard transformer lines from the major
manufacturers are wound with aluminum. Although copper wound
transformers tend to be smaller than comparable aluminum wound
transformers offer some distinct advantages over copper wound units:

Both copper and aluminum oxidize over time. Aluminum conductors
oxidize until all exposed aluminum surfaces are covered with and oxide
layer.At that point oxidation stops unless the aluminum oxide barrier
is somehow broken and the aluminum conductor is re-exposed to the air.
Aluminum oxide inhibits chemical reaction of the metal with the wire
insulation. Aluminum oxide is also a good electrical insulator. Copper
on the other hand oxidizes completely over time. Copper also acts as a
mild catalyst, hastening the decay of the wire insulation. All of
these factors combine to give aluminum wound transformers a longer
life than comparable copper wound units, typically about five years.

The heat storage capacity of aluminum is approximately 2.33 times that
of copper (specific heat of aluminum is 0.214 cal/gram/°C, specific
heat of copper is 0.092 cal/gram/°C). With aluminum wound transformers
having a superior thermal storage capacity than copper wound units,
they can withstand more surge and overload currents than copper units
(normal exhibited when a motor starts.)

Although the conductivity of copper is better than that of aluminum,
on a per pound basis aluminum is over twice as good a conductor as
copper.

Aluminum wire has received a negative connotation over the years
primarily because of the care that must be taken in making
connections. Copper proponents are quick to refer to hotel and mobile
home fires that occurred where aluminum wire was present. Upon close
examination it was found that the root causes of these problems is
related to incorrect wiring devices being used. Copper and aluminum
expand at different rates when heated. If aluminum wire is used with
wiring devices solely rated for use with copper wire, the connection
could loosen as the connection heats up causing the resistance of the
connection to increase and the temperature to continue to escalate.
Most transformer manufacturers address this problem by making a
transition between the aluminum windings, either to a copper lead wire
(or bus bar) or by terminating to an AI/Cu lug (or connector).

Q. So why are copper wound transformers still specified?

A. Copper wound units may be specified because of space limitations.
Copper wound units can also be specified due to the environment in
which the transformer will be exposed. If the environment would be
corrosive to aluminum, copper wound transformers would make sense. Of
course, some people may just like copper wound transformers for their
own reasons. Sola/Hevi-Duty manufactures aluminum wound transformers
but can manufacture copper wound transformers upon special order.
Contact your Sola/Hevi-Duty representative for pricing and
manufacturing lead times.

"Tim Williams" wrote in message
...
| Went to Ace today, as a matter of fact they carry the exact screw/clip
| dealie pictured in several replies: but it's fricking five bucks each!
| Screw it, I'll chop some (cast zinc/aluminum/bronze, or steel) bar and
make
| some screw down/mush-the-wire-in-place connectors myself.
|
| Thanks for the suggestions guys.
|
| Tim

I'll be the first to admit I'm cheap. I have four kids in private
school, yada, yada, yada. However, no appliance of mine, powered or
otherwise, will I ever put in a position to start a fire. The five bucks is
worth it, even more so when you look at quality and whatever you think your
time is worth.
Steel is an even worse choice. Dissimilar metal corrosion, lack of
spring for clamping, etc. Let your neighbors/parents know to put out a fire
watch after you're done using this "welder" for awhile. They might not
appreciate the hassle of having a fire burn away valuables.

If you don't want to pay five bucks for what will keep you safe, I can
safely assume you also don't have any fire extinguishers where you need
them. Time to rethink your priorities.

On Thu, 20 Jan 2005 17:29:04 -0600, "Tim Williams"
wrote:

For the welder rectifier I'm assembling, I need some filtering (so I hear).
Since I have some #0 AWG aluminum wire on hand I'm going to wind it around
some MOT cores. I already made one (barely managing to squeeze ten turns on
it, there's space for two more but the wire is too tough!), with about 1/16"
cardboard shim and welding the core back together (MOTs are normally welded,
I don't see anything wrong here).

My question is, what's the best way to hook up the wire to the rest of the
system? The welder's power transformer is wound with aluminum wire and just
clamped on the output terminals, so I'm guessing a washer and bolt will do.
But this is 7 strand, not solid... I might be able to do it, or it might
squish apart. I suppose I could drill a hole in a block and use a clamp
screw to hold it in place.

Tim

Not too sure what sort of welder you're building. If it's for
MIG welding you need a near constant voltage source with a filter
inductance after the rectifier. This needs a large airgap to prevent
saturation by the DC component of the welding current. Commercial
inductors are multi layer wound on a long rectangular stack of
laminations with no attempt at a closed iron circuit - typical
inductance is 300 uH - about 40T If you're using a uwave oven
transformer core 1/16 gap is not enough. Just discard one limb and
wind on the remaining "E" stack - this shape should be fairly close to
optimum.

If it's an add-on rectifier to a stick welding transformer,
the same design is OK but it's much less critical as it only makes a
small improvement in the striking and smooth running of the arc.

I just use bolt and washer termination for aluminium wire but
always include a beefy spring washer (a belville washer would be even
better) to look after the differential expansion.

Jim

While Sola's article is accurate, it has to do with distribution transformers, not wiring in your home, or a random project that hasn't been tested over and over again.

Why not just use copper wire for the choke you're making? It's easy to work with and won't burst into flames. Copper wire is thinner for any given current rating, so you'll have more room to work with, or be able to add more windings.

As for taking apart a MOT core. if you don't get a perfect fit between the laminations like they get at the factory, you will lose inductance. The welds on transformer cores are done with some sort of plasma device and don't warp the laminations.

Peter T. Keillor III wrote:
On Fri, 21 Jan 2005 04:12:38 GMT, "carl mciver"
wrote:

"Tim Williams" wrote in message
...
| For the welder rectifier I'm assembling, I need some filtering (so I
hear).
| Since I have some #0 AWG aluminum wire on hand I'm going to wind it around
| some MOT cores. I already made one (barely managing to squeeze ten turns
on
| it, there's space for two more but the wire is too tough!), with about
1/16"
| cardboard shim and welding the core back together (MOTs are normally
welded,
| I don't see anything wrong here).
|
| My question is, what's the best way to hook up the wire to the rest of the
| system? The welder's power transformer is wound with aluminum wire and
just
| clamped on the output terminals, so I'm guessing a washer and bolt will
do.
| But this is 7 strand, not solid... I might be able to do it, or it might
| squish apart. I suppose I could drill a hole in a block and use a clamp
| screw to hold it in place.
|
| Tim

Tim, the aluminum wiring has an issue that it is most critical that you
understand. When aluminum gets hot, it expands more than copper. So much
so that after a connection has been made, used to warm, then cooled, it will
get loose because the aluminum flows out of the connection. This poor
connection now creates heat due to the resistance, which starts it all over
again. Eventually a fire happens. The NEC is very concerned about the
history of this item, and has specific rules that you can't get away with
skipping.
Use connections that have "AL-CU" stamped on it and no others for that
connection. It is wise to buy a bit of antioxidizing gel, like NoAlox or
similar, and fill the connection before you assemble it with this gel. It
keeps the dissimilar corrosion away, which makes the fire issue crop up
again. Hey, it isn't inside the walls of your house, but nonetheless I
don't think you like any unnecessary action going on, even more so in a high
current connection like a welder.

Below is some interesting stuff off the FAQ on Sola's site:

Pete Keillor

--------------------------------------------------------------------------------

Q. Are copper windings better than aluminum windings?

A. As with most questions of this type pertaining to transformers, a
lot depends upon the application and the individual preferences of the
person specifying the transformer. Quite often the reason cited for
specifying copper windings is copper's high electrical conductivity.

During World War II, copper became scarce and was used primarily for
the war effort. Several industries turned to aluminum as alternative
to copper because it was in good supply, was very stable price-wise
and was less expensive than copper. In the 1940's, high-power
transmission power lines were converted from copper to aluminum and
secondary power distribution networks began utilizing aluminum in the
1950's. Today, virtually all standard transformer lines from the major
manufacturers are wound with aluminum. Although copper wound
transformers tend to be smaller than comparable aluminum wound
transformers offer some distinct advantages over copper wound units:

Both copper and aluminum oxidize over time. Aluminum conductors
oxidize until all exposed aluminum surfaces are covered with and oxide
layer.At that point oxidation stops unless the aluminum oxide barrier
is somehow broken and the aluminum conductor is re-exposed to the air.
Aluminum oxide inhibits chemical reaction of the metal with the wire
insulation. Aluminum oxide is also a good electrical insulator. Copper
on the other hand oxidizes completely over time. Copper also acts as a
mild catalyst, hastening the decay of the wire insulation. All of
these factors combine to give aluminum wound transformers a longer
life than comparable copper wound units, typically about five years.

The heat storage capacity of aluminum is approximately 2.33 times that
of copper (specific heat of aluminum is 0.214 cal/gram/?C, specific
heat of copper is 0.092 cal/gram/?C). With aluminum wound transformers
having a superior thermal storage capacity than copper wound units,
they can withstand more surge and overload currents than copper units
(normal exhibited when a motor starts.)

Although the conductivity of copper is better than that of aluminum,
on a per pound basis aluminum is over twice as good a conductor as
copper.

Aluminum wire has received a negative connotation over the years
primarily because of the care that must be taken in making
connections. Copper proponents are quick to refer to hotel and mobile
home fires that occurred where aluminum wire was present. Upon close
examination it was found that the root causes of these problems is
related to incorrect wiring devices being used. Copper and aluminum
expand at different rates when heated. If aluminum wire is used with
wiring devices solely rated for use with copper wire, the connection
could loosen as the connection heats up causing the resistance of the
connection to increase and the temperature to continue to escalate.
Most transformer manufacturers address this problem by making a
transition between the aluminum windings, either to a copper lead wire
(or bus bar) or by terminating to an AI/Cu lug (or connector).

Q. So why are copper wound transformers still specified?

A. Copper wound units may be specified because of space limitations.
Copper wound units can also be specified due to the environment in
which the transformer will be exposed. If the environment would be
corrosive to aluminum, copper wound transformers would make sense. Of
course, some people may just like copper wound transformers for their
own reasons. Sola/Hevi-Duty manufactures aluminum wound transformers
but can manufacture copper wound transformers upon special order.
Contact your Sola/Hevi-Duty representative for pricing and
manufacturing lead times.

"Crow Leader" wrote in message
...
Why not just use copper wire for the choke you're making?

Because I have the aluminum on hand (free scrap). Copper is a little harder
to come by at these prices. G

It's easy to work with and won't burst into flames.

Well, I think that's a stretch for 0 AWG, even at welder currents.

Copper wire is thinner for any given current rating, so you'll have more
room to work with, or be able to add more windings.

Not a problem, I can accept that I need more cores (or a larger one) to hold
the wire.

As for taking apart a MOT core. if you don't get a perfect fit between the
laminations like they get at the factory, you will lose inductance.

Frankly sir, I am a bit more concerned about the DC magnetizing current
reducing inductance a bit more than fitting the core in place BG

Tim

--
"I've got more trophies than Wayne Gretsky and the Pope combined!"
- Homer Simpson
Website @ http://webpages.charter.net/dawill/tmoranwms