Topics

Multiple PSx Short Circuit Protection Respond to Track Short

nwsteamer
 

My club has a large layout, primarily consisting of two large concentric loops in an 'C' shape.  Each main is about 240 feet long.  There are no crossovers between the two mainlines.  The layout is divided into three power districts powered by one Digitrax DB-150 in each district.  The layout districts can be described as dividing into a left loop district, a central district, and a right loop district.  Facing the central district, as a cross-section, you see four mainlines.  Each center section mainline piece is powered through a PSx short circuit control unit from the one booster.  (Four PSx units.)  Each mainline does have some sidings, but again there is no crossover between the loops.

This summer, the center section track was relayed and rewired. Two additional PSx units were added to this section of the layout.  The project purpose was to improve track reliability and to rearrange the sidings.  This realignment has been in operation for three or more months.

When I "quarter test" one track,  four PSx units sound off.  When I test other tracks, two or three PSx units may sound off.  For each test of a track the same PSx units always sound off.  Test different tracks activates different sets of PSx units.

Other than just very bad wiring, can anyone give me a reason for wiring PSx units in parallel?  I think it can only defeat the purpose of the PSx units.

George


john
 

Sounds a little odd. If your districts are isolated by DB150s then only one district should respond. Districts need to be isolated so that a derail doesn't take out the entire layout. 
Our club, CrossRoad RailRoad club,  layout uses PM42s to provide separation, short circuit protection and current limiting and a problem in one district only affects that district (within reason).


On Saturday, December 16, 2017 6:50 PM, "modelrr@... [WiringForDCC]" wrote:




My club has a large layout, primarily consisting of two large concentric loops in an 'C' shape.  Each main is about 240 feet long.  There are no crossovers between the two mainlines.  The layout is divided into three power districts powered by one Digitrax DB-150 in each district.  The layout districts can be described as dividing into a left loop district, a central district, and a right loop district.  Facing the central district, as a cross-section, you see four mainlines.  Each center section mainline piece is powered through a PSx short circuit control unit from the one booster.  (Four PSx units.)  Each mainline does have some sidings, but again there is no crossover between the loops.

This summer, the center section track was relayed and rewired. Two additional PSx units were added to this section of the layout.  The project purpose was to improve track reliability and to rearrange the sidings.  This realignment has been in operation for three or more months.

When I "quarter test" one track,  four PSx units sound off.  When I test other tracks, two or three PSx units may sound off.  For each test of a track the same PSx units always sound off.  Test different tracks activates different sets of PSx units.

Other than just very bad wiring, can anyone give me a reason for wiring PSx units in parallel?  I think it can only defeat the purpose of the PSx units.

George





Max Maginness
 

George

 

Wiring PSX units literally  in parallel has no  discernable  virtue.

 If I interpret your  description correctly, you took – or at least intended to take - one (or more?)  PSX protected center section(s) and split it or them into smaller subsections, each protected by newly added PSX  devices.
If this is correct  you should not have any electrical connection  between the subsections or to  the remainder of the original section(s),   if you disconnect both leads on the track side of the PSX units there should be very high resistance between all the now (electrically)  separate  track sections. If not then:

  • When you split the center section did you gap both rails  at  both ends of the new subsections?
  • Check that there were no stray lengths of track with droppers still onto the buss section now on the “wrong” side of the new subsections track gaps – may be from  one of the sidings?

Good Luck

 

Max

 

 

 

 

From: WiringForDCC@... [mailto:WiringForDCC@...]
Sent: Saturday, December 16, 2017 3:50 PM
To: WiringForDCC@...
Subject: [WiringForDCC] Multiple PSx Short Circuit Protection Respond to Track Short

 

 

My club has a large layout, primarily consisting of two large concentric loops in an 'C' shape.  Each main is about 240 feet long.  There are no crossovers between the two mainlines.  The layout is divided into three power districts powered by one Digitrax DB-150 in each district.  The layout districts can be described as dividing into a left loop district, a central district, and a right loop district.  Facing the central district, as a cross-section, you see four mainlines.  Each center section mainline piece is powered through a PSx short circuit control unit from the one booster.  (Four PSx units.)  Each mainline does have some sidings, but again there is no crossover between the loops.

This summer, the center section track was relayed and rewired. Two additional PSx units were added to this section of the layout.  The project purpose was to improve track reliability and to rearrange the sidings.  This realignment has been in operation for three or more months.

When I "quarter test" one track,  four PSx units sound off.  When I test other tracks, two or three PSx units may sound off.  For each test of a track the same PSx units always sound off.  Test different tracks activates different sets of PSx units.

Other than just very bad wiring, can anyone give me a reason for wiring PSx units in parallel?  I think it can only defeat the purpose of the PSx units.

George