Re: Large Gauge Ground Wire in Parallel with Loconet Gound Wires == Groundloop?

Mark Gurries
 


Thank you.


On Feb 24, 2018, at 9:09 AM, Chris Elliott cpelliott100@... [WiringForDCC] <WiringForDCC@...> wrote:



Hi Mark, the boosters have the model number DB210 on the front of them. They do not have any indication on them that they are opto isolated and I certainly did not order or pay for that option as it would be of no benefit to my operation.
Good question though!
Regards
Chris Elliott

Sent from planet earth

On 21 Feb 2018, at 05:46, Mark Gurries gurriesm@... [WiringForDCC] <WiringForDCC@...> wrote:


Chris,

I have one more question. Did you order the “opto" version of the DB210.  Opto and optical isolated version of the DB210?


On Feb 2, 2018, at 10:04 AM, Mark Gurries gurriesm@... [WiringForDCC] <WiringForDCC@...> wrote:



Well that explains why the booster ground wire does not work.

With these new products, what I do not know is if this is a manufacturing defect, an intentional design change by Digitrax or a accidental design omission..

One would need to examine more of these new unit to eliminate the manufacturing defect variable.

I would contact Digitrax and ask them about this.




On Jan 31, 2018, at 7:42 AM, Chris Elliott cpelliott100@... [WiringForDCC] <WiringForDCC@...> wrote:



Hi Mark, sorry for the slow response.

So as requested I've taken a few measurements and I'm a little surprised by the results, but it certainly explains a few things. My results are in the redish colour.

You asked
If you have an ohm better, check if there is continuity between the ground terminal and the metal case.
My result, I removed a case screw and stuck the probe into the thread due to all the metal having a black "coating". The measured resistance between the thread and the ground pin on the front connector was 6..8 ohms.

The next step is to measure electrical continuity between the ground terminal and the loconet ground pins 3 and 4. 
My result, to my surprise 74Kohms. Yes 74,000 ohms! This was measured between the ground pin on the front connector and the middle conductors of a dummy loconet cable.

Measurements were taken with a Fluke 1587 and the booster was totally disconnected from the layout and power supply.

Regards
Chris Elliott





On Monday, 8 January 2018, 10:46, "Mark Gurries gurriesm@comcast..net [WiringForDCC]" <WiringForDCC@yahoogroups..com> wrote:




Ok,

I have no first hand experience with the new systems.  I am not sure what has changed with the new systems.   The documentation of the new system promotes the ground wire as a AC Earth ground connection which makes no sense since it assumes that they have a safety liability situation which they do not.  They are not making the AC power supply which does have a liability situation and cannot be legally be sold unless it addresses that safety issue per UL, ETL or equivalent safety agency requirement.

Anyway, if it is intended as a Earth Ground connection, then it must be connected to the metal chassis.

If you have an ohm better, check if there is continuity between the ground terminal and the metal case.  There should be if supposed to fulfill its safety requirement.

The next step is to measure electrical continuity between the ground terminal and the loconet ground pins 3 and 4.   I know there is on the older Digitrax systems.  I measured it and you know it works because your suing the large ground wire with the older systems..   If the new system BREAKS that continuity, that would explain why the large ground wire does not work and you must relay on the Digitrax Loconet ground for the booster common function.






On Dec 30, 2017, at 3:01 AM, Chris Elliott cpelliott100@... [WiringForDCC] <WiringForDCC@...> wrote:



I have a DCS100 as the command station. In loconet port A I have a UR92 connected and that’s it. In loconet port B I have the loconet cable that runs to the other boosters. There are no other loconet devices connected anywhere. On the DCS100 the “home ground” is connected to the little digitrax installed pigtail. This pigtail is connected to a lug which is held against the rear heat sink.. 

The “home ground” wire runs for approx 14 metres before reaching the first and second boosters, it is a 2.5 millimetre cable (approx awg 13) It does not connect to anything else.
The “home ground” wire connects to the ground terminal on the front of a DB210 and then daisy chains off to the second DB210 and connects the same way.

I had previously wired a friends layout which has a DCS100 and six DB150’s configured as boosters. I had cut the loconet cables as described in Alan Gartners “booster wiring” and it works without issue.

So when I installed the booster loconet cable on my layout, I cut the wires as described on Alan’s website and as I’d done previously. But the DB210’s would not wake up. The LEDs on the front on the DB210 were not correct and trains would not run on the DB210s power districts. The both rails at boundary between power districts are gaped and insulated. Reterminating the booster loconet cable so that all 6 wires are connected corrected the issue.


Sent from planet earth

On 30 Dec 2017, at 11:53, Mark Gurries gurriesm@... [WiringForDCC] <WiringForDCC@...> wrote:


How did you make the ground connection?  Details please.

On Dec 26, 2017, at 6:51 PM, Chris Elliott cpelliott100@... [WiringForDCC] <WiringForDCC@...> wrote:



Yes, I had installed a heavy gauge “home ground” between the boosters and command station. 

Sent from planet earth

On 27 Dec 2017, at 11:15, Mark Gurries gurriesm@... [WiringForDCC] <WiringForDCC@...> wrote:


Did you have the ground wire installed?


On Dec 24, 2017, at 8:28 PM, Chris Elliott cpelliott100@... [WiringForDCC] <WiringForDCC@...> wrote:



I’ve found that the new digitrax boosters won’t come on line if the ground wires in the loconet cables are cut.
Chris Elliott

Sent from planet earth

On 25 Dec 2017, at 04:50, nwsteamer modelrr@... [WiringForDCC] <WiringForDCC@...> wrote:

Mark,

The way I read this statement the large gauge wire in parallel to the 
Loconet 'ground'  wires does constitute a 'loop' and could cause a 
reliability problem...

Thus, the recommendation in Allan Gartner's website to cut the Loconet 
'grounds' at the boosters is valid.  Do you agree?

On 12/24/2017 05:03 AM, Mark Gurries gurriesm@... [WiringForDCC] 
wrote:
> Adding the large gauge parallel ground wire permitting a ground loop 
> to be establish is the LESSER of the two evils. 




Best Regards,

Mark Gurries
Electrical Engineer
DCC Website & NMRA DCC Clinics: www.markgurries.com







Best Regards,

Mark Gurries
Electrical Engineer
DCC Website & NMRA DCC Clinics: www..markgurries.com







Best Regards,

Mark Gurries
Electrical Engineer
DCC Website & NMRA DCC Clinics: www.markgurries.com








Best Regards,

Mark Gurries
Electrical Engineer
DCC Website & NMRA DCC Clinics: www.markgurries.com






Best Regards,

Mark Gurries
Electrical Engineer
DCC Website & NMRA DCC Clinics: www.markgurries.com







Best Regards,

Mark Gurries
Electrical Engineer
DCC Website & NMRA DCC Clinics: www.markgurries.com



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