Could an old DC power controller damage a modern loco?

[Pete the Elaner]

4 hours ago, andyman7 said:

As others have noted, there is a separate thread on the issue of persisting with old controllers. The conversations falls into two parts:

 

1) the risk of harm to the user from using very old kit where the insulation may have broken down and/or other parts used in construction may have deteriorated so as to pose a risk to health. To summarise this debate, if the users' electrical knowledge extends to just plugging it in, it's time to stop. Those with electrical knowledge and the confidence to repair/rewind/renew/replace components are a different matter, but no-one should be using a controller of great age just because they've never got round to replacing it.
 

2) the risk of harm to mechanisms. As the OP says, for many years the maxim that 12v DC was 12v DC was 'good enough' because there were usually no components between the pickups and what was normally  a hardy motor that was capable of taking a pretty wide range of voltages, including spikes. Even then, things such as 'half wave rectification' could cause overheating if used too much. This pretty much changed from the early 2000s when RTR locos began to use circuit boards to manage lighting and motor current and 'can' motors became the norm - having taken the top off a Bachmann loco circa 2003 recently it's astounding how simple the early circuit boards were, but they and their associated components have quickly grown in complexity and are allied to mechanisms that are much more sensitive - that is what gives us fine slow speed running and smooth drive characteristics but they do want an equally smooth delivery of current from an electronic controller without PWM.   

 

3. Old resistance mat controllers provide very poor slow speed control. I have heard others claim otherwise, but when I have seen their layouts run, it is clear that they have no concept of how a train really accelerates.

Edited January 28 by Pete the Elaner

[melmerby]

37 minutes ago, Pete the Elaner said:

3. Old resistance mat controllers provide very poor slow speed control

The H&M mats were available in a variety of resistancies to suit the current required by the loco.

If you are attempting to control a modern loco with a low resistance one it will be hopeless, however with the correct (higher resiatance) mat it should be fine.

 

Edited January 28 by melmerby

[kevinlms]

12 hours ago, melmerby said:

The H&M mats were available in a variety of resistancies to suit the current required by the loco.

If you are attempting to control a modern loco with a low resistance one it will be hopeless, however with the correct (higher resiatance) mat it should be fine.

 

I agree, but how does one identify which resistance mat is fitted? I've asked here several times and the question has been ignored, even by those that swear by Duettes, etc. I suspect that they do in fact have the high resistance versions.

[melmerby]

7 hours ago, kevinlms said:

I agree, but how does one identify which resistance mat is fitted? I've asked here several times and the question has been ignored, even by those that swear by Duettes, etc. I suspect that they do in fact have the high resistance versions.

I don't know

I bought two skeleton* controllers maybe 50 years ago and I chose which resistance I wanted but there is nothing on the mats (AFAIK)  to identify which.

I've still got them and can use them if necessary but as you say, they don't control modern locos very well, so presumably lowish rersistance.

 

* the basic unit without case or power supply to incorporate in your own panel.

[John M Upton]

On 25/01/2024 at 20:08, markwilson said:

It’s a Lone Star and now you can see why I said it’s pretty old! 

I’ve disconnected it and put my old Gaugemaster D on (technically not an O gauge controller, but these Dapol units don’t pull as much current as my Heljan stock). Seemed to be running fine, but still a slight whiff from the DMU after 10 minutes running in each direction, so I may just need to accept these models are not made to run continuously.

 

My layout is end to end, so that shouldn’t be a challenge…

 

That antique should be nowhere but in a skip.  I would be interested to know if it has ever been PAT tested, if it is in use in a publicly accessible location such as a club room, it should be tested annually.

[melmerby]

36 minutes ago, John M Upton said:

That antique should be nowhere but in a skip.

Maybe a museum of horrors?🙂

[kevinlms]

14 hours ago, melmerby said:

I don't know

I bought two skeleton* controllers maybe 50 years ago and I chose which resistance I wanted but there is nothing on the mats (AFAIK)  to identify which.

I've still got them and can use them if necessary but as you say, they don't control modern locos very well, so presumably lowish rersistance.

 

* the basic unit without case or power supply to incorporate in your own panel.

Measuring the overall resistance may supply an answer?

[Southernman46]

On 28/01/2024 at 11:13, andyman7 said:

As others have noted, there is a separate thread on the issue of persisting with old controllers. The conversations falls into two parts:

 

1) the risk of harm to the user from using very old kit where the insulation may have broken down and/or other parts used in construction may have deteriorated so as to pose a risk to health. To summarise this debate, if the users' electrical knowledge extends to just plugging it in, it's time to stop. Those with electrical knowledge and the confidence to repair/rewind/renew/replace components are a different matter, but no-one should be using a controller of great age just because they've never got round to replacing it.
 

2) the risk of harm to mechanisms. As the OP says, for many years the maxim that 12v DC was 12v DC was 'good enough' because there were usually no components between the pickups and what was normally  a hardy motor that was capable of taking a pretty wide range of voltages, including spikes. Even then, things such as 'half wave rectification' could cause overheating if used too much. This pretty much changed from the early 2000s when RTR locos began to use circuit boards to manage lighting and motor current and 'can' motors became the norm - having taken the top off a Bachmann loco circa 2003 recently it's astounding how simple the early circuit boards were, but they and their associated components have quickly grown in complexity and are allied to mechanisms that are much more sensitive - that is what gives us fine slow speed running and smooth drive characteristics but they do want an equally smooth delivery of current from an electronic controller without PWM.   

That's the main reason I ditched the "Powermaster" due to the potential 😁 for damage to the electronics of the more recent motive power purchases I've made but secondly I've just held on to it tooooooo long (typical electrical engineer's arrogance). I need something modern.

[markwilson]

Just to add a (possibly final) comment to this thread, the club has replaced the old controller with a Morley. I’ve not tested any of my stock on it yet, but for those of you with safety concerns about the old unit, I thought I’d just add this!

 

[MattTovey]

I had a Kato controller which I did not realise at the time came with a power pack suitable for N gauge and for many months used it to power 00 track and only realised should have use a dedicated 00 gauge Kato transformer instead when came to sell it and saw on Ebay others with either N or OO gauge power packs.  However, my 00 gauge stock ran fine with the N gauge power pack. 

[kevinlms]

2 hours ago, MattTovey said:

I had a Kato controller which I did not realise at the time came with a power pack suitable for N gauge and for many months used it to power 00 track and only realised should have use a dedicated 00 gauge Kato transformer instead when came to sell it and saw on Ebay others with either N or OO gauge power packs.  However, my 00 gauge stock ran fine with the N gauge power pack. 

The only difference (if indeed any!), is that the N Gauge power pack would put out less volts, thus ensuring N Gauge motors don't get cooked.

Running modern OO (it's probably advertised by Kato as HO), is fine, because they use less current than older motors.

 

So continue using it, without dramas.