Short circuit detection and protection with DCC.


tootnkumin

tootnkumin

Well-Known Member
Staff member
My club has a dual purpose layout, can be switched to operate in either DC or DCC. It relies on the automotive light method of short detection/protection i.e. it doesn't cut the track power completely but absorbs the overload with the bulbs and as soon as the reason for the short is corrected, operation can resume. Is this a sufficient or advisable solution for DCC, or should another method be employed?
 
Toot: In my experience, with DCC the Command booster should shut down the power should a short occur. Using a lamp for over load protection with a modern DCC system is not necessary nor advisable.

A better cure for shorts with a DCC system is a series of electronic circuit breakers added to the wiring.

Check out this site for more information:

ww.rr-cirkits.com/Notebook/short.html

Greg
 
We use Digitrax at the club and any short will immediately shut the power down. Once the short has been cleared, it automatically resets. Due to the size of the layout, there are three boosters.
 
Greg@mnrr said:
Toot: In my experience, with DCC the Command booster should shut down the power should a short occur. Using a lamp for over load protection with a modern DCC system is not necessary nor advisable.

A better cure for shorts with a DCC system is a series of electronic circuit breakers added to the wiring.

Check out this site for more information:

ww.rr-cirkits.com/Notebook/short.html

Greg
Click to expand...

Thanks for that link, Greg. I'll print that off and run it past the club's electrician. There's 3 bulbs involved in the setup and maybe he's got that last mentioned method in use. Power always get's restored once the short's cause is found and corrected, but that sometimes can take a while.
 
tootnkumin said:
It relies on the automotive light method of short detection/protection i.e. it doesn't cut the track power completely but absorbs the overload with the bulbs and as soon as the reason for the short is corrected, operation can resume. Is this a sufficient or advisable solution for DCC, or should another method be employed?
Click to expand...
that is a very common overload indication and protection solution. Personally I could not say it is not advisable (as it is published in a couple of DCC books written by experts). On the other hand I will say that I find it not preferable. When there is a short I want the power to shut down, not just be "browned out". I prefer command stations and boosters that automatically sense short circuits and shutdown the power with an internal "breaker". I believe most of the brands I own (CVP, Digitrax, Lenz, and NCE) all restart automatically when the short is corrected.
 
Iron Horseman said:
that is a very common overload indication and protection solution. Personally I could not say it is not advisable (as it is published in a couple of DCC books written by experts). On the other hand I will say that I find it not preferable. When there is a short I want the power to shut down, not just be "browned out". I prefer command stations and boosters that automatically sense short circuits and shutdown the power with an internal "breaker". I believe most of the brands I own (CVP, Digitrax, Lenz, and NCE) all restart automatically when the short is corrected.
Click to expand...
Thanks IH, yes the DCC system is NCE. The light bulb method on the club layout is a hangover from it's DC only days and the fact that it is still used for that on a regular basis. I do wonder if it can interfere with the correct operation of the NCE's short circuit detection and control and be a factor in causing the loss of consist information in one or more locos in a consist when a short occurs. Probably has never been any in depth investigation as to whether it might.
 
Toot:

The auto lamp will not affect the operation of your DCC system other than creating an additional electrical load on the system.

Think of it as a large locomotive headlight.

Greg
 
Toot: Your reply brings up a question about 1:1 locomotives. What voltage were their headlights in general?

Thanks.

Greg
 
Greg@mnrr said:
Toot: Your reply brings up a question about 1:1 locomotives. What voltage were their headlights in general?

Thanks.

Greg
Click to expand...
I remember reading many years ago that the New Zealand Rly mainline steamers were 24V, but with the amount of light put out by modern diesel headlights, could be less, could be more, depending on the type of "bulbs" used. Do they use LED's now?
 
You must log in or register to reply here.



Back
Top