N Gauge Forum

General Category => N Gauge Discussion => Topic started by: TrevL on November 03, 2018, 08:16:28 AM

Title: Risk of induced voltage???
Post by: TrevL on November 03, 2018, 08:16:28 AM
Before I attached the baseboard, I drilled a series of 10 mm holes through the bearers for the wiring.  Now, the top is firmly fixed and the track layed and wiring has commenced, I realise I have neglected to drill sufficient holes near the NCE controller panel and adjacent track mimic.  In escence, through one of the holes, I have the track bus, the power lead for the NCE, the power lead for CDU, common return from the point motors and, two pairs of wires for two sets of points. these are all through one 10mm hole and as you can imagine, it's pretty tight. 
Is there the potential for interference/ induced voltage do you think?  TIA.
Title: Re: Risk of induced voltage???
Post by: ntpntpntp on November 03, 2018, 09:14:57 AM
I wouldn't worry about it, the voltages are too low to create any significant magnetic field enough to induce anything meaningful in nearby wiring.
Title: Re: Risk of induced voltage???
Post by: Bealman on November 03, 2018, 10:53:51 AM
Agree. Most model railways have thick wiring looms with no problems.
Title: Re: Risk of induced voltage???
Post by: NinOz on November 03, 2018, 11:16:32 AM
Quote from: TrevL on November 03, 2018, 08:16:28 AM
<snip>
Is there the potential for interference/ induced voltage do you think?  TIA.
This was a hot topic on a discussion group early this year.  Generally opinions were divided into: Yes, No and Maybe.
From what I could condense from the conflicting opinions were:
1. Possible between conductor sets with long, long runs of cables in close parallel, hauling some impressive AC currents.
2. For long runs simply twisting the cables will mitigate or remove any such interferences.
3. For all the chatter, no examples of such interferences were tended for proof of concepts.
4. Should not be a problem for most layouts.

Much of these discussions head rapidly off into theoretical/unlikely scenarios rather than normal applications.

CFJ
Title: Re: Risk of induced voltage???
Post by: joe cassidy on November 03, 2018, 12:07:16 PM
Sounds a bit like the debate about whether expensive loudspeaker cables are better than using any old bit of flex ?

Best regards,


Joe
Title: Re: Risk of induced voltage???
Post by: TrevL on November 03, 2018, 12:23:36 PM
Thank you all, I was just a bit worried that when I fired a point, the jolt from the CDU would interfere with the carrier signal on the track bus. Thanks for putting my mind at rest, and saves me from trying to drill another horizontal hole in a bearer next to the underside of the baseboard.
:thankyousign:
Title: Re: Risk of induced voltage???
Post by: Newportnobby on November 03, 2018, 01:10:01 PM
You could always cut a notch in the base of battens and then fasten wires into it by screwing a piece of plasticard/wood over the notch if necessary.
Title: Re: Risk of induced voltage???
Post by: John Mac on November 03, 2018, 02:08:56 PM
My take is that there will be some crosstalk and coupling between the different cables, but that it won't be of a level that will cause problems.

The cables you describe aren't carrying low level signals, which is where you might notice problems. DCC is a pretty low frequency and quite tolerant of noise.

Cheers,

John.
Title: Re: Risk of induced voltage???
Post by: Malc on November 03, 2018, 05:31:24 PM
As Ntpntpntp says, the currents in the conductors are very small and wouldn't induce anything in adjacent wires.
Title: Re: Risk of induced voltage???
Post by: edwin_m on November 03, 2018, 05:47:54 PM
Worst case would be the big pulse of current when operating a solenoid point motor.  But as it's also very short, even if it disrupts the DCC signal the decoders should keep running during a short interruption.  The only thing I'm aware of where interference is a possible issue is the Lenz RS bus.  Mine got more reliable once I installed separate screened twisted cables instead of sharing a ribbon cable with the DCC signal for the accessories.