Where to Source - 100k 3W Carbon Comp Resitor?
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Re: Where to Source - 100k 3W Carbon Comp Resitor?
Thank you I'll PM him,
Looking at the website it seems the allen bradley carbon comp resistors max out at 2W. I've found this to be true searching on the internet as well which leads me to ask.
Are we sure they made 3 watts and we aren't just guessing on the schematic? Most clones are using other types of resistors due to the trouble sourcing them.
Looking at the website it seems the allen bradley carbon comp resistors max out at 2W. I've found this to be true searching on the internet as well which leads me to ask.
Are we sure they made 3 watts and we aren't just guessing on the schematic? Most clones are using other types of resistors due to the trouble sourcing them.
My Daughter Build Stone Henge
Re: Where to Source - 100k 3W Carbon Comp Resitor?
Ohmite and Allen Bradley have not in the past and currently do not offer a 3W resistor....
My Daughter Build Stone Henge
Re: Where to Source - 100k 3W Carbon Comp Resitor?
Allen Bradley did make 3 & 4 watts CC models. I have a few of the 3W industrials.selloutrr wrote:Ohmite and Allen Bradley have not in the past and currently do not offer a 3W resistor....
TM
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Re: Where to Source - 100k 3W Carbon Comp Resitor?
I might be missing something but the Data sheets confirm they don't exist.ToneMerc wrote:Allen Bradley did make 3 & 4 watts CC models. I have a few of the 3W industrials.selloutrr wrote:Ohmite and Allen Bradley have not in the past and currently do not offer a 3W resistor....
TM
The 3W and 4W resistors have heat sinks built into them. They are not the correct style of CC resistor used in TW builds. The correct body style is not available above 2W.
The best you can do would be a RCR42 2W 100k @ +/- 5% 750V keeping with the correct body style.
My Daughter Build Stone Henge
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Re: Where to Source - 100k 3W Carbon Comp Resitor?
I think that might be true.
I think the issue might be whether people are off-handily referring to the mil-spec wattage or a general use wattage since those allen bradleys were mil-spec parts.
The 2watt mil specs could be referred to as a 3watt part.
I have some carbon comps that are the size of a medium sized mallory150 cap but I think those are still 2watt.
surplus sales only lists up to 2 watts as well.
http://www.surplussales.com/Resistors/R ... onComp.htm
they are pricier then the others though.
I think the issue might be whether people are off-handily referring to the mil-spec wattage or a general use wattage since those allen bradleys were mil-spec parts.
The 2watt mil specs could be referred to as a 3watt part.
I have some carbon comps that are the size of a medium sized mallory150 cap but I think those are still 2watt.
surplus sales only lists up to 2 watts as well.
http://www.surplussales.com/Resistors/R ... onComp.htm
they are pricier then the others though.
- Noel Grassy
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Re: Where to Source - 100k 3W Carbon Comp Resitor?
I bought a sack of 2W A/B carbon comps and they look for all the world to
be the same size as the ones in Francesca. I too couldn't find any 3W CC
types when I was sourcing parts so I gambled on the 2W resistors. I'm glad
to see this being addressed here. Especially by folks with access to OEM's
data sheets.
Noel Grassy.
be the same size as the ones in Francesca. I too couldn't find any 3W CC
types when I was sourcing parts so I gambled on the 2W resistors. I'm glad
to see this being addressed here. Especially by folks with access to OEM's
data sheets.
Noel Grassy.
All excellent things are as difficult as they are rare__B Spinoza
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Re: Where to Source - 100k 3W Carbon Comp Resitor?
The discrepancy for me lies in the size of a 2W CC resistor compared to a 1W, 1/2W, 1/4W, etc.. Below is a pic for reference (this is Steve aka ApexJr's pic).
This starts with 1/8W, then 1/4W, then 1/2W, 1W and finally 2W resistors. I used to think these big ones were 3W as well but this size IS 2 Watts. Someone might have been mistaken when they made the Express BOM or accidentally hit a "3" instead of a "2" but as far as I can tell (seems you guys agree), nobody made a 3W carbon comp resistor in this size. I haven't seen any mil-spec 2W-sized CC resistors labeled as 3W in my years of collecting parts.
Who said it was a 3W part anyways? I'm pretty sure I settled on this Wattage being incorrect and I personally just use 2W resistors in my Express with no issues.
[img:533:456]http://honeybeeamps.files.wordpress.com ... stors1.jpg[/img]
This starts with 1/8W, then 1/4W, then 1/2W, 1W and finally 2W resistors. I used to think these big ones were 3W as well but this size IS 2 Watts. Someone might have been mistaken when they made the Express BOM or accidentally hit a "3" instead of a "2" but as far as I can tell (seems you guys agree), nobody made a 3W carbon comp resistor in this size. I haven't seen any mil-spec 2W-sized CC resistors labeled as 3W in my years of collecting parts.
Who said it was a 3W part anyways? I'm pretty sure I settled on this Wattage being incorrect and I personally just use 2W resistors in my Express with no issues.
[img:533:456]http://honeybeeamps.files.wordpress.com ... stors1.jpg[/img]
Cliff Schecht - Circuit P.I.
Re: Where to Source - 100k 3W Carbon Comp Resitor?
The idea of the 3W comes from the Franchesca gut shot that is labeled. Later that was the basis for the schematics and just assumed to be correct.
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My Daughter Build Stone Henge
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Re: Where to Source - 100k 3W Carbon Comp Resitor?
Yeah those are clearly 2W guys consistent with the pics I posted and everything else discussed in this thread. I wonder how many other people have been smashing their heads against the wall trying to find 3W CC resistors (like selloutrr ). I know I spent a good month or so digging through ALL of the carbon comp resistors in the EE stockroom when I was building my first Express and never found any labeled 3W (at least at that size). Every resistor I've seen that size was either in a 2W bin, in a bag labeled 2W or it was clearly written on the resistors body with higher precision parts (e.g. I've got some 56k 2W CC resistors white font on the body, otherwise they are standard shape/size/color with value bands). In other words, I learned the hard way that these resistors do not exist, at least not in the form that the Francesca picture implies.
Cliff Schecht - Circuit P.I.
Re: Where to Source - 100k 3W Carbon Comp Resitor?
I looked through my stock of NOS cc and did not find any 3W but the data sheets shown from AB do show 3W cc.
I wouldn't worry about it and just use the 2 watters.
Mark
I wouldn't worry about it and just use the 2 watters.
Mark
Re: Where to Source - 100k 3W Carbon Comp Resitor?
the AB 3W CC have a heat sink. It's a hybrid resistor.
everything else above 2W is wire wound.
everything else above 2W is wire wound.
My Daughter Build Stone Henge