VAX-11/750 power supplies

[Jon Elson]

On 04/08/2015 01:50 AM, Mattis Lind wrote:
>
> However looking in the print set the diode is listed as 1114197-00 with the
> remark "60 AMP POWER SCHOTTKY DIODE"
>
> Is the Unitrode USD5096F a 60 Amp diode? This link tells me it is a 35A
> diode:
>
> http://www.electronicsurplus.com/unitrode-usd5096f-diode-35amp-35v-piv
> and so does this link:
> http://www.ebay.com/itm/35-Amp-35-Volt-Stud-Mounted-Diode-with-Wire-and-Lug-Wind-and-Solar-Blocking-/271653646843?pt=LH_DefaultDomain_0&hash=item3f3fd1b1fb
>
> Is there anyone that can enlighten me here? Is USD509F a 35 Amp part and
> then why have DEC used parts that is not as specified in the print set?
>
>
Notes written on the schematic are commonly a bit off.  
Depending on the peak to average ratio of the current and 
the temperature it is expected to operate at, you can get 
very different values. Typically, the manufacturer give 
hugely inflated ratings in their data sheets, and the OEM 
has to run them at much reduced ratings to get reliable 
operation.

Jon