Author Topic: Identify PCB?  (Read 903 times)

0 Members and 1 Guest are viewing this topic.

Offline wd5jfrTopic starter

  • Regular Contributor
  • *
  • Posts: 149
  • Country: us
Identify PCB?
« on: August 22, 2020, 04:07:15 pm »
Found at a hamfest.  Looks like some kind of heavy duty power filter. Any ideas.
 

Offline wraper

  • Supporter
  • ****
  • Posts: 17952
  • Country: lv
Re: Identify PCB?
« Reply #1 on: August 22, 2020, 04:15:57 pm »
3 phase mains filter. Nothing special about it.
Similar to this except it does not have bleeding resistors:
 

Offline wd5jfrTopic starter

  • Regular Contributor
  • *
  • Posts: 149
  • Country: us
Re: Identify PCB?
« Reply #2 on: August 22, 2020, 04:52:32 pm »
That was quick thanks.
 

Offline wd5jfrTopic starter

  • Regular Contributor
  • *
  • Posts: 149
  • Country: us
Re: Identify PCB?
« Reply #3 on: August 22, 2020, 06:38:48 pm »
Good inspection but it  has 3 you couldn't see because of the camera angle.The 1.5uf caps are rated at 275Vac.  So it must have been on a 240Vac system.  The toroids are wound with No. 8 wire but the PCB traces would not have anywhere near the current carrying capacity.  The lower resistance of No. 8 wire would result in a higher Q but I wonder if that's important in 60 Hz power filter.  I'm  curious if this was done because they just stocked heavy toroids.
 

Offline wraper

  • Supporter
  • ****
  • Posts: 17952
  • Country: lv
Re: Identify PCB?
« Reply #4 on: August 22, 2020, 07:23:50 pm »
Good inspection but it  has 3 you couldn't see because of the camera angle.The 1.5uf caps are rated at 275Vac.  So it must have been on a 240Vac system.
If you look at the schematic I provided, those caps make star connection. So 275V X2 caps work perfectly for 400V 3 phase or anything with lower voltage. And yeah, there are bleeding resistors after all, they were simply hidden on the first photo.
 

Offline wd5jfrTopic starter

  • Regular Contributor
  • *
  • Posts: 149
  • Country: us
Re: Identify PCB?
« Reply #5 on: August 23, 2020, 12:26:38 am »
Any idea of why they used N0. 8 wire to wind the toroids?
 

Offline wraper

  • Supporter
  • ****
  • Posts: 17952
  • Country: lv
Re: Identify PCB?
« Reply #6 on: August 23, 2020, 07:53:26 am »
It seems that traces to inductors go on both sides of PCB thus have higher current carrying capability that it may seem. Wire thickness does not seem disproportionate to me.
 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf