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Omega Help Area => Omega Electrical and Audio Help => Topic started by: GastronomicKleptomaniac on 12 April 2017, 16:03:59

Title: Bridge rectifiers... why?
Post by: GastronomicKleptomaniac on 12 April 2017, 16:03:59
I have in my workshop a pair of bridge rectifiers, IIRC removed from the headlamps of my old ex plod.

Im wondering if theyll ever be useful - I assume it was to do with the wigwags or strobes, given they were spliced into the headlamp feeds from what I remember and have left over...?
Title: Re: Bridge rectifiers... why?
Post by: zirk on 12 April 2017, 17:32:07
Probably not much use but might be worth keeping (depends on the rating Amps). They could have been used for a few things, but if were part of the Head Light wiring would of probably been used for the WigWags.

Most of the newer stuff, ie Wellen Modules etc, interrupt the headlight wiring altogether then effectively rewire the Lights from the module. Some of the older stuff that used Relays etc, they would have been used for DC blocking, the idea being as you put 12v on one of the Head Lights the other lights up as there wired together, so to get the Head lamps to flash in turn you block each headlight in turn, the diodes would have probably been used to drive relays rather than directly, some simple diode and relay trickery, pso that the lights would still flash whether the main headlights were on or off.
Title: Re: Bridge rectifiers... why?
Post by: Doctor Gollum on 12 April 2017, 19:02:36
 I used these...

http://www.ebay.co.uk/itm/Woodway-headlight-flasher-unit-for-ambulance-fire-rescue-recovery-vehicle-12V-/192110514812?&_trksid=p2056016.l4276

... to good effect, one for main beam and one for rear fogs 8)
Title: Re: Bridge rectifiers... why?
Post by: Marks DTM Calib on 18 April 2017, 13:54:44
They will have been to diode OR the cars headlights in with the plod flashing
Title: Re: Bridge rectifiers... why?
Post by: GastronomicKleptomaniac on 21 April 2017, 22:28:52
Forgot I'd posted this! I'll keep them in the shed but electrics is something of the dark arts to me... :y Cheers chaps!
Title: Re: Bridge rectifiers... why?
Post by: Migv6 le Frog Fan on 22 April 2017, 18:04:18
Me too. I'm still convinced its witchcraft.  :y
Title: Re: Bridge rectifiers... why?
Post by: Chazza12 on 24 April 2017, 12:30:01
what part number are they the Bridge rectifiers, ?
Title: Re: Bridge rectifiers... why?
Post by: minifreek on 24 April 2017, 19:47:16
Why would there be bridge rectifiers installed into an already DC system....?

Always thought they was used to convert from an AC source to DC source....?
Title: Re: Bridge rectifiers... why?
Post by: Andy H on 24 April 2017, 20:09:38
Why would there be bridge rectifiers installed into an already DC system....?

Always thought they was used to convert from an AC source to DC source....?
Because it is a convenient way to install two, high current, diodes in an insulated package with a single bolt fixing. (and yes - I know there are 4 diodes in a bridge rectifier.......)
Title: Re: Bridge rectifiers... why?
Post by: Omega VT3000 on 25 April 2017, 14:56:27
Why would there be bridge rectifiers installed into an already DC system....?

Always thought they was used to convert from an AC source to DC source....?
Because it is a convenient way to install two, high current, diodes in an insulated package with a single bolt fixing. (and yes - I know there are 4 diodes in a bridge rectifier.......)

Yep, wired up the same way by me on my Polac. There are four diodes in the package. In order to get alternate flashing headlights (or main beam on xenon equipped cars) you cut in to the bulb feed and connect the headlight +ve to a common cathode, the headlight feed from the car to one anode and the flasher feed to the other anode.