Need help with DALE resistors.

[Sagen]

Hi, I try to understand. On datasheet for Vishay/Dale CMF Industrial the CMF55 goes as a 1/2 W.
On datasheet for Vishay/Dale CMF ( Military RN and RL ) the CMF55 goes as 1/8 W.
And see RN60 are sold as 1/4 W, but we use it as a 1/2 W ?

Help!! ( :

Frank

 

[UserAbuser]

Military rating vs Domestic rating.
It's all there if you read the product pdf's.

 

[jbau]

Military rating vs Domestic rating.
It's all there if you read the product pdf's.

Actually I find the data sheet not very clear in this respect. All it says is "Commercial equivalents of military styles are available with higher power ratings. Consult factory."

Also note that all CMF's and RL's are not alike. The CMF07 (RL07) and CMF20 (RL20) are NOT nonmagnetic.

 

[Lingwendil]

The military parts are derated for reliability but otherwise very much the same as the consumer/commercial market parts.

 

[rayma]

There's an option ( -143 ) for nonmagnetic leads at the end of the part number, see this sheet.
This has been confusing since the 70s. Buy the copper leaded resistors if possible.

 

[Sagen]

Here I have CMF55, CMF60 and RN60D. Non of them is magnetic.

 

[soundchaser]

As I understand it the power ratings are temperature dependent. The CMF-55 is good for 0.5W up 70 deg C but derates linearly to 0.25W at 125 deg C. For the parts in the data sheet the power ratings at 125 deg are half what they are at 70 deg.

 

[jbau]

I have thousands of Dale RNxx's on hand, mostly on pcb's from over the last 40 or so years. 99.9% of them are nonmagnetic. Same with their exact CMF counterparts.
Similarly, I have never bought an RN55/60/65 from Mouser or Digikey that were magnetic. So they must get all -143 parts.
This is not true for the CMF07 or CMF20, though. They have tinned copper leads but ferrous end caps.