Older locos stop when the change powered sections on Z21

[reddragon]

My older Hornby / Lima locos that pick up from one rail via the motor bogie and the other rail via the trailer bogie stop as the bridge the change in powered sections on my railway. As I have 3 sections, locos pass power section changes often!

 

Is there an issue with the set up of the Z21 or is this a common issue?

 

I am going to experiment with fitting capacitors to stop this happened, but would like to know what options I might have.

 

thanks

[RFS]

I had this problem when using the Lenz LZV100 and LV102 booster. The solution was to connect the ground terminals between the two boosters (LV102 and internal LV102 in the LZV100). No doubt a similar arrangement exists for the Z21 and is perhaps in the documentation? My problem wasn't actually locos, but Hornby Pullmans which pick up from the side of one bogie and the opposite side of the other. This meant the lights went out when they crossed the power section breaks.

 

EDIT: This is what Lenz say:

 

"In some scales there exist locomotives that have pickups that are offset from each other. For example many steam locomotives have power pickup from one rail in the locomotive and the other rail in the tender. When such a locomotive bridges the gap between isolated power stations, the locomotive will stall because the circuit is not complete. The solution to this problem is to provide a common wire between all the power stations. All DCC command control systems need to have such a common provided, if offset pickup locomotives are to be operated."

Edited March 20, 2021 by RFS

[reddragon]

Hmm, I'd need to research this as doing it wrong and blowing up a Z21 + twin booster, and maybe locos.

 

Anyone actually done it on a Z21 and can explain how & the risks?

[WIMorrison]

Do you have the Z21 and the Z21 booster connect via CAN and have you set the booster to inherit the settings from the Z21.

 

and just be 100% certain do you’ve the polarities correct?

[Junctionmad]

Interestingly, the Roco booster manual is entirely quiet on the issue of grounding **  seperate boosters , even though it’s exactly what  the issue is. 

 

** by grounding , I mean establishing a common 0V reference on the power supplies to the boosters. 

 

All the power supplies to any device feeding the rails needs to have a common 0V to prevent return currents finding incorrect return paths. 

[reddragon]

On 20/03/2021 at 21:35, WIMorrison said:

Do you have the Z21 and the Z21 booster connect via CAN and have you set the booster to inherit the settings from the Z21.

 

and just be 100% certain do you’ve the polarities correct?

 

The Z21 is correctly connected to the Z21 booster via CAN and there is no apparent option for grounding / common.

 

I have fitted 1 loco with a stay alive and it crosses the section gap faultlessly without stopping.

[reddragon]

I have now added a stay alive to most of my split pick up locos, solving the issue.

[SamThomas]

On 20/03/2021 at 21:35, WIMorrison said:

and just be 100% certain do you’ve the polarities correct?

Agreed - the power outputs of all "power districts" &/or programming track (if part of the running tracks) need to be in phase with each other.