Do I need a power booster?

[GrumpyPenguin]

5 hours ago, GrumpyPenguin said:

This discussion is a perfect example of "a little knowledge can be dangerous".

 

I've made my points as a professional electrical engineer who spent most of his time fault finding/putting other peoples work right (a lot of it on 12v display lighting so working in similar voltages as being discussed here but far, far higher currents, up to 50a) but apparently I don't know what I am talking about.

 

My layout (24' x 10') has had the wiring installed & tested as I've already described & never felt the need for crude "coin tests" as I'm confident with my work. As it happens I've had the odd derailments at the futhest point from the boosters & instant trip out.

I'm using a Z21 & 2 x Lenz boosters.

 

I'm now finished with commenting, other people looking for advice can make their own choices based on what they read.

 

Enjoy the rest of your Bank Holiday Weekend.

I should have finished with ;

"I'm not going to bite to any further comments - feel free to have the last say".

[Andymsa]

3 hours ago, GrumpyPenguin said:

I should have finished with ;

"I'm not going to bite to any further comments - feel free to have the last say".

maybe you don’t wish to comment further, but I did ask a fair question how did you test for short circuit operation without using the coin test.

[Derekl]

On 04/05/2024 at 11:36, RikkiGTR said:

 

May be hard to see but I've marked on the plan where I have feeds for the fiddle yard.

Truth be told it may be an issue with under-gauge wire used for the main bus - I got it from Amazon and it is Chinese, it does feel quite flimsy and is probably not 32/0.2, so I'm going to remove the entire bus and replace it with much heavier wire and see if that sorts out the issue.

 

It looks to me that you have feeds for each full length of track in the fiddle yard, but not for each track section. You need feeds on each individual piece of track, so that you are not relying on rail joiners for continuity. You should also be feeding point frogs through the motor switch, which isn't apparent from this diagram (but may simply not appear).

[melmerby]

6 minutes ago, Derekl said:

 

It looks to me that you have feeds for each full length of track in the fiddle yard, but not for each track section. You need feeds on each individual piece of track, so that you are not relying on rail joiners for continuity. You should also be feeding point frogs through the motor switch, which isn't apparent from this diagram (but may simply not appear).

I would agree with that, rail joiners are a problem waiting to happen. They don't always cause problems but eliminating the possibility is good practice.

Providing feeds whilst building a layout saves a lot of work later, if they are needed.

[Andymsa]

28 minutes ago, melmerby said:

I would agree with that, rail joiners are a problem waiting to happen. They don't always cause problems but eliminating the possibility is good practice.

Providing feeds whilst building a layout saves a lot of work later, if they are needed.

I always solder every metal rail joiner

[RFS]

1 hour ago, Andymsa said:

I always solder every metal rail joiner

 

Does that not then prevent heat expansion in hot weather with the risk of rails buckling?

[Ron Ron Ron]

2 hours ago, Andymsa said:

I always solder every metal rail joiner

 

38 minutes ago, RFS said:

 

Does that not then prevent heat expansion in hot weather with the risk of rails buckling?

 

An alternative would be to solder short jumper wires, thereby overcoming the expansion issue.

 

.

[Andymsa]

55 minutes ago, RFS said:

 

Does that not then prevent heat expansion in hot weather with the risk of rails buckling?

heat expansion is not an issue, firstly I allow expansion with the rail isolation joiners. Also the room is temp controlled with air conditioning.

[melmerby]

26 minutes ago, Andymsa said:

the room is temp controlled with air conditioning.

Lucky You🙂

 

Mine varies between 0 & 35 Celcius

[Crosland]

On 04/05/2024 at 12:59, melmerby said:

So 60 ohms per km and current rating at a given temperature isn't a good enough description?

That wasn't in the post I quoted. It was a simple current rating, therefore my comment stands.

[Crosland]

15 hours ago, Andymsa said:

maybe you don’t wish to comment further, but I did ask a fair question how did you test for short circuit operation without using the coin test.

Disconnect everything from the track and short the rails at the furthest point from the command station/booster. Measure the resistance between the rails where the CS was connected. Ohms law will tell you the maximum current that will flow, given your track voltage. If it's enough to trip the booster (you want some margin to allow for uncertainties such as component tolerances in the booster) then you are good to go.

[Andymsa]

7 minutes ago, Crosland said:

Disconnect everything from the track and short the rails at the furthest point from the command station/booster. Measure the resistance between the rails where the CS was connected. Ohms law will tell you the maximum current that will flow, given your track voltage. If it's enough to trip the booster (you want some margin to allow for uncertainties such as component tolerances in the booster) then you are good to go.

 

The reason I asked the question was there are so many variables in resistance values and what end result you get by measuring alone, you can design but actual testing is vital.

 Using measurements for testing is only the first part as this only proves wire resistance. Removing the command stations/boosters would skew the resistance in the circuit. Then what about track detection these units introduce resistance, or if you have installed snubbers. yes you can measure with a volt meter but how many know how to use one or even have one, even the OP admits they didn’t have one. Yes I agree that it’s an important part of your tool kit, to me the coin test is much better as a final test as all elements are in circuit, it is a simple test that no one would have difficulty in using and you get a definitive result. Also you eliminate any faults within the component element ie the command station/booster has a fault not shutting down.

[Andymsa]

 

my testing methodology 🤣

[Derekl]

21 hours ago, Andymsa said:

I always solder every metal rail joiner

Except that, unless i am missing something, this isn't your layout, so the fact that you solder all the joiners doesn't really help the OP with his question. (Unless you are the OP under a changed identity).

[Andymsa]

9 minutes ago, Derekl said:

Except that, unless i am missing something, this isn't your layout, so the fact that you solder all the joiners doesn't really help the OP with his question. (Unless you are the OP under a changed identity).

I was responding to another poster, but I would disagree as it could be relevant to the OP original question as they state a slow down in a specific area. 

[WIMorrison]

1 hour ago, Derekl said:

Except that, unless i am missing something, this isn't your layout, so the fact that you solder all the joiners doesn't really help the OP with his question. (Unless you are the OP under a changed identity).

On the contrary, it is very relevant.

 

If the OP (or anyone else) doesn't have enough power connections from the bus to the track and is relying on rail joiners then that is a route to problems, and those problems can be overcome by soldering the rail joiners to the rail. I use this technique regularly and it is very effective.

[melmerby]

3 hours ago, WIMorrison said:

On the contrary, it is very relevant.

 

If the OP (or anyone else) doesn't have enough power connections from the bus to the track and is relying on rail joiners then that is a route to problems, and those problems can be overcome by soldering the rail joiners to the rail. I use this technique regularly and it is very effective.

But not recommended if you get large variations in temperature.

I found out the hard way when I had not allowed enough expansion gap and when it hit 35C the track buckled.

If you solder you have no expansion room at all.

[WIMorrison]

Hasn’t caused me any issues with the temperature varying from below freezing to the recent extremely warm summers.

[melmerby]

1 hour ago, WIMorrison said:

Hasn’t caused me any issues with the temperature varying from below freezing to the recent extremely warm summers.

Please tell me how you have overcome the laws of physics😀

[Andymsa]

35 minutes ago, melmerby said:

Please tell me how you have overcome the laws of physics😀

as I said previously using the isolation rail joiners is one way, laying track in hot weather is another solution .

[Free At Last]

When I was doing my first loft layout back in the '70s I thought I was being savvy by soldering the track joints instead of using rail joiners. I must have done it during the summer as from what I can remember most of the joints fractured.

[spamcan61]

1 minute ago, Free At Last said:

When I was doing my first loft layout back in the '70s I thought I was being savvy by soldering the track joints instead of using rail joiners. I must have done it during the summer as from what I can remember most of the joints fractured.

Typical solder, having significant lead content, isn't very strong, it isn't designed to be. Soldering the rail joiners isn't going to stop thermal expansion so something's going to give at the end of the day.

[Steven B]

On 06/05/2024 at 10:11, Crosland said:

Disconnect everything from the track and short the rails at the furthest point from the command station/booster. Measure the resistance between the rails where the CS was connected. Ohms law will tell you the maximum current that will flow, given your track voltage. If it's enough to trip the booster (you want some margin to allow for uncertainties such as component tolerances in the booster) then you are good to go.

 

All very wise and sound advice. I'd still want to physically test that the CS actually handles a short-circuit correctly before putting any locos on the layout. It's hard to do that without actually triggering a short.

 

None of this helps the OP from finding their gremlin!

 

@RikkiGTR are you any closer to fixing your problem?

 

Steven B

 

[Andymsa]

21 minutes ago, Steven B said:

 

All very wise and sound advice. I'd still want to physically test that the CS actually handles a short-circuit correctly before putting any locos on the layout. It's hard to do that without actually triggering a short.

 

None of this helps the OP from finding their gremlin!

 

@RikkiGTR are you any closer to fixing your problem?

 

Steven B

 

although not directly related to the OP original issues, there could be benefit to it. As the issue was a slow down and potential resistance problem that could translate into shut down issues during a short.

[Colin_McLeod]

I prefer to solder to the rail rather than to the rail joiner.

 

Firstly it avoids the expansion issue, and secondly if problems are caused by unreliable conduction through the rail joiners, what is the benefit of soldering to the rail joiner?