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Edward

NCE system - fault between 2 separate power districts

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My layout is divided into 2 power districts using the NCE Power Cab system.  Each district is wired via a 3 pole double throw switch ( 1 pole is for LED indicator powered by a separate 12v power pack) from the track feed output.  In each district there are about 20 DCC concepts Omega IP point motors which are controlled by the handset using the select accy buttons.  I've set up several macros and they work fine.  The 2 districts are joined at the moment by a single piece of track with insulated joiners.  Each point has been modified to allow the polarity to be changed by a micro-switch:  in this case switched directly by the frog terminal  on the IP motor.  Of course all the polarity changes were checked.

Locos run successfully within each districts with point changes. 

 

However running a loco over the join results in an immediate stop and a buzzing noise from the loco. The amps reading on the handset jumps to 2.27A from about 0.6 - 1.0. 

My thoughts were " obviously got the feed wires the wrong way round!" .  Swopped them round : no change, just the same.  Also noticed that the red light on the PTP only dimmed, I expected it to go out completely.

 

I found if you run a loco fast enough you can get it over the join sometimes by switching out the departing district. 

(Not sure if this is relevant but I've installed a control panel using the Alpha Switches and the Alpha Encoder Units plus a second UTPanel with a second handset.  But I disconnected these so they can't effect things.  But not working for yet consistently.  This in one district only).

 

Can anyone suggest what's going on here and any ideas to fix it ?  Any help gratefully received !!

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My layout is divided into 2 power districts using the NCE Power Cab system.  Each district is wired via a 3 pole double throw switch ( 1 pole is for LED indicator powered by a separate 12v power pack) from the track feed output.  In each district there are about 20 DCC concepts Omega IP point motors which are controlled by the handset using the select accy buttons.  I've set up several macros and they work fine.  The 2 districts are joined at the moment by a single piece of track with insulated joiners.  Each point has been modified to allow the polarity to be changed by a micro-switch:  in this case switched directly by the frog terminal  on the IP motor.  Of course all the polarity changes were checked.

Locos run successfully within each districts with point changes. 

 

However running a loco over the join results in an immediate stop and a buzzing noise from the loco. The amps reading on the handset jumps to 2.27A from about 0.6 - 1.0. 

My thoughts were " obviously got the feed wires the wrong way round!" .  Swopped them round : no change, just the same.  Also noticed that the red light on the PTP only dimmed, I expected it to go out completely.

 

I found if you run a loco fast enough you can get it over the join sometimes by switching out the departing district. 

(Not sure if this is relevant but I've installed a control panel using the Alpha Switches and the Alpha Encoder Units plus a second UTPanel with a second handset.  But I disconnected these so they can't effect things.  But not working for yet consistently.  This in one district only).

 

Can anyone suggest what's going on here and any ideas to fix it ?  Any help gratefully received !!

Are you using two handsets on the basic system?

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Are you using two handsets on the basic system?

No not for the test.  I did have both plugged in to start with but unplugged Cab No 3 and the UTP when I got the fault.

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No not for the test.  I did have both plugged in to start with but unplugged Cab No 3 and the UTP when I got the fault.

I'll be honest your requirements are somewhat beyond my skills and I'm sure their are other more knowledgeable members in this group who will take me to task,  But I know when Giz (from this forum) and myself tried two handsets on my last layout, Loch Dore layout we could never get two handsets to work on the basic 2 amp setup (you have renumbered the second handset?).

The problem was resolved by getting the NCE Smart Booster and a 5amp power pack and now no problems. I've never used power districts as i find the gaugemaster DCC frog juicers for points resolve any shorts that happen round the points area.

Edited by sharkman

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Do you have one or two Power Cabs (and associated mains power supplies)?

 

Do you have any short circuit protection on each of the power districts?

 

In the absence of any mention of an additional unit e.g. an SB5 or similar booster, how is the track power arranged?

 

I don't think you can use two Power Cabs (with associated mains power supplies) on the same layout. One has to be treated as a Pro Cab so that only one throttle is the "command" station.

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I'll be honest your requirements are somewhat beyond my skills and I'm sure their are other more knowledgeable members in this group who will take me to task,  But I know when Giz (from this forum) and myself tried two handsets on my last layout, Loch Dore layout we could never get two handsets to work on the basic 2 amp setup (you have renumbered the second handset?).

The problem was resolved by getting the NCE Smart Booster and a 5amp power pack and now no problems. I've never used power districts as i find the gaugemaster DCC frog juicers for points resolve any shorts that happen round the points area.

The problem we had was when using a PowerCab with another acting as a slave, then if there was a short, both cabs would react to it and whilst the PowerCab would reset when it was removed the slave would freeze and only reset if unplugged. Using the SmartBooster stopped this.

 

Edward seems to have a different problem. I think we need more info on how the power districts are powered up.

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The problem we had was when using a PowerCab with another acting as a slave, then if there was a short, both cabs would react to it and whilst the PowerCab would reset when it was removed the slave would freeze and only reset if unplugged. Using the SmartBooster stopped this.

 

Edward seems to have a different problem. I think we need more info on how the power districts are powered up.

I agree.

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My layout is divided into 2 power districts using the NCE Power Cab system.  Each district is wired via a 3 pole double throw switch .....

 

 

...In the absence of any mention of an additional unit e.g. an SB5 or similar booster, how is the track power arranged?

 

 

..... I think we need more info on how the power districts are powered up.

 

 

Edward, you say two power districts.

Are these....

1. each powered by their own booster, the PowerCab being one of those boosters; 

2. ...or are they sub-districts, powered from the single PowerCab handset's booster and divided by a power management device(s) (e.g. circuit breaker).

3. Otherwise, is it just a single power district (powered by the PowerCab, with the power bus split into two by the 3 pole switch?

 

If you could clarify that, it might help.

 

 

.

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Edward, you say two power districts.

Are these....

1. each powered by their own booster, the PowerCab being one of those boosters; 

2. ...or are they sub-districts, powered from the single PowerCab handset's booster and divided by a power management device(s) (e.g. circuit breaker).

3. Otherwise, is it just a single power district (powered by the PowerCab, with the power bus split into two by the 3 pole switch?

 

If you could clarify that, it might help.

 

 

.

 

It's like your No 3:   The track feed from the Panel is split into 2 sets of 2 wires which each run to one terminal of the switch. The other "end" of the switch leads to the pair of track feeds for each "district" of the layout.

 

To answer the other questions:  the second cab works as a slave ( ie as a ProCab) with a different Cab address. It is plugged into the UTPanel using the curly cord and the panel is connected via a flat lead that is plugged into the spare socket on the front of the Power Cab panel.  But I have unplugged this anyway so I don't think it would effect anything.  ( It is a problem that I need to solve next!)

 

I will try to draw and post a diagram later- I think I'll have to scan it to load it onto this forum.  This will be a first for me. 

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Have you traced out your wiring with a multimeter?

From your reply to Ron and previous - you have 1 Power District (ie ONE power Supply generating dcc)  and simply the option of isolating either or both of the track sub-districts or sections - with no other electronics such as intelligent breakers involved.

 

You would be better with the 'Power indicator' LEDs run from the track-side of the isolating switches - a combination of LED, 1N4148 protective diode (against excess reverse voltage) and a resistor of > 1k ohm  - so that they show the presence of track power ????

 

Have you tried removing the LED/indicator wiring and power supply - and ensured no internal connection within the switches

(hence checking with a meter both for continuity and voltage)    Do you have any tracks whose power is switched by points ????

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Hi Edward.

 

Why have you separated the layout into the 2 districts?

 

Is it just so you can shut off one half?

 

What you've done won't help with short circuits, if this is why you have taken this route.

 

I would be having one of the bus wires bypassing the switch. I.e. Common return is you wish to use the term.

 

Re the two throttles, I seem to remember that after a short when the Power Cab shuts down and restarts, the 2nd throttle working as a Pro Cab needs to boot up after the Power Cab has booted.

 

I cannot locate the info at the moment but I seem to remember there is a setting to delay the second cab reboot.

 

Dave.

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Have you traced out your wiring with a multimeter?

From your reply to Ron and previous - you have 1 Power District (ie ONE power Supply generating dcc)  and simply the option of isolating either or both of the track sub-districts or sections - with no other electronics such as intelligent breakers involved.

 

You would be better with the 'Power indicator' LEDs run from the track-side of the isolating switches - a combination of LED, 1N4148 protective diode (against excess reverse voltage) and a resistor of > 1k ohm  - so that they show the presence of track power ????

 

Have you tried removing the LED/indicator wiring and power supply - and ensured no internal connection within the switches

(hence checking with a meter both for continuity and voltage)    Do you have any tracks whose power is switched by points ????

Your first para is correct-no boosters etc- just the simple 2 wires to the track.

 

I'll think about trying that about the LEDs later

 

All my points get their power from the track bus and the internal switch changes the polarity of the frogs.  I've looked underneath the boards but can't see anything obviously wrong.  But of course each boards work ok on their own! 

 

I have checked the voltages and continuity I think they're OK. 

 

Picking up your suggestion,  I'll bypass the switches and feed the track directly and see what happens.

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Hi Edward.

 

Why have you separated the layout into the 2 districts?

 

Is it just so you can shut off one half?

 

What you've done won't help with short circuits, if this is why you have taken this route.

 

I would be having one of the bus wires bypassing the switch. I.e. Common return is you wish to use the term.

 

Re the two throttles, I seem to remember that after a short when the Power Cab shuts down and restarts, the 2nd throttle working as a Pro Cab needs to boot up after the Power Cab has booted.

 

I cannot locate the info at the moment but I seem to remember there is a setting to delay the second cab reboot.

 

Dave.

Hi Dave  Thanks so much for your comments.   My ideas were if we had 2 people operating and a fault occurred, I could switch off one section and and the other person could carry on operating the other section.  Then find the fault.  The LEDs were supposed to be a bit of fun! 

I've tried out the 2 throttles and they seem to work ok , the slave does seem a bit slow when selecting a loco and I can operate all the points from both plus the locos. 

 

However the GOOD news is that I bypassed the switches, feeding the track bus directly and hey presto everything works!! Even the DCC Concepts panel with Alpha switches,  operates as intended.   

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Now all is well,  I think I'll abandon the LED idea and get back to bringing the "permanent way" up to a reasonable standard.   I don't really understand what was going wrong - a wiring fault or a more complicated DCC problem. 

 

Anyway many thanks indeed for the replies

 

Cheers

 

Edward

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Now all is well,  I think I'll abandon the LED idea and get back to bringing the "permanent way" up to a reasonable standard.   I don't really understand what was going wrong - a wiring fault or a more complicated DCC problem. 

 

Anyway many thanks indeed for the replies

 

Cheers

 

Edward

Hi,

 

Did you verify that both "districts" were wired in-phase?

 

You have to be sure that each wire from the command station goes to the same rail in both sections.

 

Frederick

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You could look at the switches to see if the contacts were as you thought 8-)  

I approve of the 'geographic' idea of isolating an area for faultfinding in the case of a problem - it is what I do although I start from 4 actual power districts - then further local subdivision as required - all normally left 'on'.

Back at the 'central panel' I have 3 rows of switches - 1 for track dcc,  1 for acc. dcc, and the 3rd for the 16Vac for acc. decoders -

each can be isolated for each area (power district or sub district... )  All have the LED on the track/output side of the switch and will therefore light up if (for track) as metal wheel bridges a section gap OR if testing at the track with a 9V battery (track power off 8-) ) the LED will light to verify the connection back to the switch panel ... (in 1 direction .... what I SHOULD have done is use 2 LEDS, in Inverse Parallel - with eg 1 red, 1 green, so that the phase or ac nature is clearly shown at all times.

I also use RRampmeters for voltage and current - BUT if you want cheap Voltage monitoring on the layout - from Ebay you can get Automotive Voltage Modules ('0'-30Vdc ... self powered from about 3V) for 3-6GBP each .... just add a bridge rectifier and 'allow 1.4V error' in the reading .... note - if you plan on using Railcom, then you will need a capacitor AFTER the bridge, so as to smooth over the gap, othrwise the display's processor resets, and you get no reading displayed!

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Been v busy over the weekend being the Club annual show in Stamford so haven't answered the latest posts. A lot to mull over in the next day or so and "inwardly digest". Yes I think it might be a stray wire strand causing intermittent shorts. Moral is take more care when soldering!

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