Toroid Cores

 * Original msg to: tesla-at-grendel.objinc-dot-com
 * Carbons sent to: Esondrmn-at-aol-dot-com

 > From: Esondrmn-at-aol-dot-com
 > To: tesla-at-grendel.objinc-dot-com
 > Subject: Toroid forms

 ES> Does anyone know where I can purchase toroid coil forms in   
 ES> the 2.0 to 3.0 inch diameter range?  Needed for RF chokes.
 ES> Thanks, Ed Sonderman

Get the latest catalog from Marlin P. Jones & Assoc. Inc.
P.O.BOX 12685, Lake Park, FL  33403  USA
Fax 1-800-4329-9937, Fax 407-844-8764, Tel: 407-848-8236

They have part# 5065-CH, Ferrite Toroid Core priced at $1.50
each. Though a bit smaller than you are looking for (these are 
1-1/2 inches OD),  for most coiling work up to 2 kVA these will
work fine and have room for a dozen or so turns of wire.

I have found even larger ferrite toroid cores in this catalog
(they update about four times a year if you order regularly), 
but they were already wound with wire. No problem, I stripped the
thinly insulated magnet wire off, wrapped the cores in a few
layers of electrical tape, and then rewound the cores with
heavily insulated stranded wire. The pre-wound chokes were about
$1.75 each, and I should have bought a dozen, as the bare ferrite
cores weigh almost 1/4 pound.

Also: for those power control cabinet scavengers, this is the
same catalog that carries the AC current transformers for
converting a standard 5 amp AC ammeter into a 0 - 60 amp meter.
The part number for this little gem is 3955-TR priced at $8.95,
and once or twice a year you will find a 5 amp meter in the same
catalog that has the 0 - 60 scale...

Also: they have 30 amp EMI filters (part# 3994-FL), $5.94 each,
special 8 units or more $4.95 each (brand new). I have eight of
these, and they are top quality units with RF choked ground
pathing built right into the box! Run the ground wire reversed
and you will get virtually no interference back to the breaker

Richard Quick

... If all else fails... Throw another megavolt across it!
___ Blue Wave/QWK v2.12