collapse

* Who's Online

  • Dot Guests: 35
  • Dot Hidden: 0
  • Dot Users: 3
  • Dot Users Online:

* Recent Topics/Posts

CPD Software ? by John Li
[Today at 02:48:46 PM]


Ultra-wide screen displays w/ BMS? by RUS
[Today at 02:34:27 PM]


F-16's in Afganistan Documentary by Rufus
[Today at 02:19:15 PM]


Grease Monkey's Pit by sagrzmnky
[Today at 01:57:29 PM]


Group Buy for X40 Dual Stepper Motors for PSCockpit by ZoomOut
[Today at 11:51:50 AM]


AiRdAncE's Pit v.2.0 by Auke104
[Today at 11:31:17 AM]


Warning panel by The_target
[Today at 08:37:38 AM]


Uri's Pit by Beesty
[Today at 08:27:36 AM]


Landing gear with locking/release by chnil71
[Today at 03:31:31 AM]


MailMan's Pit by MailMan
[November 26, 2014, 05:19:12 PM]


Parts 3D Models by Hempstead
[November 26, 2014, 02:04:10 PM]


amido's pit by Snowman
[November 26, 2014, 11:52:26 AM]


PSCockpit System Fourth Run!!! by magoo
[November 26, 2014, 11:12:20 AM]


Phantom CDU for computer interface by mrwell
[November 26, 2014, 10:18:00 AM]


Request pics landing gear panel F-16A by Auke104
[November 26, 2014, 07:00:09 AM]


MANTRIM PHCC daughter board by mrwell
[November 26, 2014, 03:04:51 AM]


Rednecks ICP project [WIP] by mrwell
[November 26, 2014, 02:52:26 AM]


eBay heads-up by mrwell
[November 25, 2014, 04:09:30 PM]


Henkie's pit by henkie
[November 25, 2014, 01:11:09 PM]


Compiling PHCC .asm files using MPLAB-X by Willy
[November 25, 2014, 09:51:11 AM]

Author Topic: Negative voltage at AIC backlight?  (Read 3173 times)

Offline Rufus

  • General
  • ******
  • Join Date: Feb 2012
  • Location: California
  • Posts: 1613
  • Country: us
Re: Negative voltage at AIC backlight?
« Reply #60 on: December 23, 2013, 02:11:22 AM »
Ok...I think I've noodled something out about the Mean Well supply.  I went back and looked at the block diagram again, and it appears that while the G/G (COM, in the diagram) and mains earth may not be directly tied together they are internally shared somehow - with with a capacitor between the high side and mains earth presumably to create some delay/over voltage protection for given channels.  But it looks as if the circuit branches are self-draining at shut down, so nothing to worry about there.

I'm thinking though that I shouldn't ground my pit structure to/through the supply earth though, because a back EMF could harm the protective capacitors...but that I can use the wall plug ground over a separate cord with only the ground wire connected?  I'd lift this circuit with a relay at MAIN POWER - other than OFF, maybe with a slight delay.
- Rufus

Offline Cupra

  • General
  • ******
  • Join Date: Jun 2009
  • Location: Solothurn
  • Posts: 783
  • Country: ch
    • 1st VFW "Glory Wings"
Re: Negative voltage at AIC backlight?
« Reply #61 on: December 23, 2013, 02:17:28 AM »
@dkm
Oops, that has gone under... or how ever you say  :harhar:

Yes, everything else is working without anny issues. Boards are dedected and at the power supply Pins of the boards the +12V DC is stable with the Switch on and it is 0,00 when the Switch is off.
The exact same circuit (a second one) is connectet to the backlight-connectors and there I have the -14V when i Switch off. But bowth funktions are working without problems or thermal abnormalities.
So for me I would say if eveything works proper there is no Need to do anything... I am just always a litte afraid if I have voltages I canīt explain  :notes: