Date   
Re: Digest Number 2081 Hot Snubber

jazzmanlj
 

Maybe it's time to put the hot snubber to bed and open a discussion as to loops and wiring! That might be more informative and productive.

Len Jaskiewicz

Re: Hot Snubber

Max Maginness
 

Err…  I think you have your Joules and BTU’s  tangled here……

 

Max

 

From: WiringForDCC@... [mailto:WiringForDCC@...] On Behalf Of dvollrath@...
Sent: Saturday, March 15, 2014 9:09 AM
To: WiringForDCC@...
Subject: Re: [WiringForDCC] Re: Hot Snubber

 

 

The definition of 'hot' is subjective. If you pinch a resistor between your fingers for 4 or 5 seconds and it is dissipating even 1/4 watt it will feel 'hot'. 1/4 watt for 4 seconds (1 watt-second = 1 Joule) and is enough heat energy to raise the temperature of one pound of water one degree F. Compare the mass of your fingers with a pound of water and you can guess how long it will take to raise the temperature of your finger to a sensitive or even uncomfortable level. If the capacitor is shorted, the resistor will see full track voltage across it. 14V x 14V / 100 ohms = nearly 2 watts.

 

If you have substituted a different R & C network in that same location and it does not get 'hot', the original capacitor is either the wrong value or faulty. Please throw it out and let's get off this subject.

 

DonV


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Re: Digest Number 2081 Hot Snubber

CS_listes
 

 
Hello,
  Posted by: "Ed S" Date: Fri Mar 14, 2014 8:23 pm
>His instructions recommend not to using a continuous loop but he
does not give a reason.

The answer is here: NMRA
Standard S-9.1.2 - 5 end of section.
http://www.nmra.org/standards/sandrp/pdf/S-9.1.2_2012_07.pdf
“5. Topology
Only one Command Station signal generator output or Power Station Interface Repeater output
155 may be connected to a Power Station Interface. Inputs of many Power Stations may be connected
in parallel connection to the two wires of the bus. It is acceptable to use tree, star, and daisy chain
connections. However, it is not allowed to connect any part of this bus in a loop. The bus, or
branches, must not create a loop to themselves or to another branch. If multiple Power Station
Interfaces are used on a layout, they must not be interconnected. They should be clearly identified
160 to eliminate possible cross connecting.”
 
This implies that it is the same track. They should not form a loop.

Good day digital.
Charles_2_Bordeaux.
France.
 
Bonjour,
La réponse est ici :
Cela sous-entend qu’il en est de même pour les rails. Ils ne doivent pas former une boucle.
Bonne journée en numérique.
Charles_2_Bordeaux.
France.

Re: Hot Snubber

William Teeters <cozyflyr9398@...>
 

Rich, Is your buss wire still in a loop? If so, Cut it at a distal distance, and see the results. Bill



From: "redking56@..." <redking56@...>
To: WiringForDCC@...
Sent: Saturday, March 15, 2014 11:41 AM
Subject: RE: [WiringForDCC] Re: Hot Snubber

 
Steve, the hot snubber had a 1/2 watt resistor, and I initially replaced the 1/2 watt resistor with a 1 watt resistor, but the problem persisted.  When I replaced the capacitor and retained the 1 watt resistor, the snubber became a lot less hot to the touch.

Rich


Re: Hot Snubber

redking56@...
 

Steve, the hot snubber had a 1/2 watt resistor, and I initially replaced the 1/2 watt resistor with a 1 watt resistor, but the problem persisted.  When I replaced the capacitor and retained the 1 watt resistor, the snubber became a lot less hot to the touch.

Rich

Re: Hot Snubber

Flash Gordon
 

Rich,

Yes that seems to be the solution.

Now run some trains and have fun.

Ed S

At 12:29 PM 3/15/2014, you wrote:


Yes, that is correct.

So, I take it that leaving the bus wires disconnected at that point would be the way to resolve the matter.

No more "continous loop" as I call it, relative to the bus wires.

Rich

Re: Garden layouts/Booster Protective Housing

jazzmanlj
 

We can put this subject to bed!

Best to have multiple boosters in one location out of the elements. A central control/wiring is best.  I'm not concerned about quality of wire in the elements. It takes years for problems to arise and things always change.

 

Thanks all,

Len Jaskiewicz

Re: Hot Snubber

Steve Haas
 

 

<<Just now, I went down and inserted the hot snubber on my bus wires over by snubber #6 where that snubber is warm at best.  Very quickly, the resistor on that hot snubber got extremely hot, for whatever that is worth.>>

 

 

Rich, 

 

Is there any chance the resister in the “hot” snubber is of too small a wattage?  That alone could cause the resistor to run hot (see another recent conversation on this topic).  I’m willing to bet the “hot” snubber has a lower wattage resistor compared to the others. Replace the resistor with at least a ½ watt resistor and see what happens.

 

Best regards,

 

 

Steve Haas

Snoqualmie, WA

 

Re: Hot Snubber

redking56@...
 

Thanks, Steve.

Rich

Re: Hot Snubber

redking56@...
 

Yes, that is correct.

So, I take it that leaving the bus wires disconnected at that point would be the way to resolve the matter.

No more "continous loop" as I call it, relative to the bus wires.

Rich

Re: Hot Snubber

Steve Haas
 

<<This question may have gotten lost in all of these exchanges.>>

 

<<Does it matter how many feeders are between two snubbers?>>

 

No – the number of feeders between snubbers makes no difference.

 

<<Does it matter what type of device is connected to a feeder besides rail, such as an NCE Switch-It or Mini-Panel or Circuitron Flasher, or Digitrax AR-1?>>

 

NO – device types do not matter.

 

 

Best regards,

 

Steve Haas

Snoqualmie, WA

 

Re: Hot Snubber

Flash Gordon
 

If I understand, when you disconnected the loop between the R/F Filters , the resistors stayed cool...

Bingo...

Ed S

At 11:53 AM 3/15/2014, you wrote:

disconnected the bus wires just to the right of the #3 snubber, Waited several seconds, then touched the resistor on the #4 snubber. It was cool to the touch.

Rich

Re: Hot Snubber

redking56@...
 

Bill, isn't that kind of a low blow after all of this input?

Or are you just kidding?

Yes, I have a layout, 25' x 42'.




---In WiringForDCC@..., <cozyflyr9398@...> wrote :

Rich, Do you have a layout, Or do you just Have an  inquiring mind, say to broaden your knowledge?. Bill T



From: "redking56@..." <redking56@...>
To: WiringForDCC@...
Sent: Saturday, March 15, 2014 4:33 AM
Subject: [WiringForDCC] Re: Hot Snubber

 

Let me throw another consideration into the mix.
Am I doing myself a disservice by even having snubbers on my bus wires?
Rich




Re: Hot Snubber

William Teeters <cozyflyr9398@...>
 

Rich, Do you have a layout, Or do you just Have an  inquiring mind, say to broaden your knowledge?. Bill T



From: "redking56@..."
To: WiringForDCC@...
Sent: Saturday, March 15, 2014 4:33 AM
Subject: [WiringForDCC] Re: Hot Snubber

 

Let me throw another consideration into the mix.
Am I doing myself a disservice by even having snubbers on my bus wires?
Rich




Re: Hot Snubber

redking56@...
 

LOL

DONE !!!


---In WiringForDCC@..., <dvollrath@...> wrote :

If you have substituted a different R & C network in that same location and it does not get 'hot', the original capacitor is either the wrong value or faulty. Please throw it out and let's get off this subject.


DonV

Re: Hot Snubber

dvollrath@...
 

The definition of 'hot' is subjective. If you pinch a resistor between your fingers for 4 or 5 seconds and it is dissipating even 1/4 watt it will feel 'hot'. 1/4 watt for 4 seconds (1 watt-second = 1 Joule) and is enough heat energy to raise the temperature of one pound of water one degree F. Compare the mass of your fingers with a pound of water and you can guess how long it will take to raise the temperature of your finger to a sensitive or even uncomfortable level. If the capacitor is shorted, the resistor will see full track voltage across it. 14V x 14V / 100 ohms = nearly 2 watts.


If you have substituted a different R & C network in that same location and it does not get 'hot', the original capacitor is either the wrong value or faulty. Please throw it out and let's get off this subject.


DonV

Re: Hot Snubber

redking56@...
 

OK, here is what I just did.

I disconnected the bus wires just to the right of the #4 snubber.  The resistor was very warm to the touch.

So, I reconnected the #4 snubber and disconnected the bus wires just to the right of the #3 snubber,  Waited several seconds, then touched the resistor on the #4 snubber.  It was cool to the touch.

Then, I reconnected the bus wires next to the #3 snubber, waited several seconds, and then touched the resistor on the #4 snubber.  It was warm to the touch once again.

Thoughts?

Rich

Re: Hot Snubber

redking56@...
 

I tend to think that it is the capacitor because yesterday I did that test with some new 1W resistors in place of the 1/2 W resistor and the problem persisted.

Rich

Re: Hot Snubber

Flash Gordon
 

I believe you have some bad resistors or capacitors. I would get rid of any that get that hot.

The Ramp meter gives average voltage, it does not read/ give the spikes. Only an oscilloscope will do that, but they are there.

Ed S

At 11:32 AM 3/15/2014, you wrote:


LOL

Ed, you may stay up. I should have mentioned it at the outset but, Yes, I am HO scale.

I do have a RRampMeter on my layout, and it shows a constant 14.7 to 15.4 volts. It is wired in-line, though, so I do not use it portably to check for voltage spikes or drops.

Incidentally, I did replace the hot snubber yesterday, and the replacement runs a lot cooler, or maybe I should say, less hot.

Just now, I went down and inserted the hot snubber on my bus wires over by snubber #6 where that snubber is warm at best. Very quickly, the resistor on that hot snubber got extremely hot, for whatever that is worth.

Rich

Re: Hot Snubber

redking56@...
 

LOL

Ed, you may stay up.  I should have mentioned it at the outset but, Yes, I am HO scale.

I do have a RRampMeter on my layout, and it shows a constant 14.7 to 15.4 volts.  It is wired in-line, though, so I do not use it portably to check for voltage spikes or drops.

Incidentally, I did replace the hot snubber yesterday, and the replacement runs a lot cooler, or maybe I should say, less hot.

Just now, I went down and inserted the hot snubber on my bus wires over by snubber #6 where that snubber is warm at best.  Very quickly, the resistor on that hot snubber got extremely hot, for whatever that is worth.

Rich


---In WiringForDCC@..., <eschwerkolt@...> wrote :

Rich,

That should work, now cut the bus loop. Replace the hot R/C
Filter. It should help.

Layman's explanation of spike. I think we are all assuming you are
in HO scale. If you are in Lionel O gauge 3 rail, then I am going back to bed.

On a perfect layout the constant voltage on the rail is around 14
volts. When a spike occurs the voltage can jump to 24 to 38 volts As
per Gartner.

This would fry decoders. The R/C Filters (snubbers) soak up the
excess. What can cause the spikes. Your 200 feet of wire holds a lot
of electricity, it is moving back and forth.

Now a big guess.... the wave of spikes are being absorbed by the #4
R/C filter.

Ed S


At 10:45 AM 3/15/2014, you wrote:
>
>
>OK, I probably have already effectively accomplished that because
>between #3 and #4 snubbers, the rails of my double mainline track
>are gapped for occupancy detection. Wouldn't that be sufficient?
>
>Rich