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.

[Tumut]

HelloAll, regarding H&M Controllers with a Full Wave and a Half Wave Switch, UNDER NO CIRCUMSTANCES USE HALF WAVE ON A MODERN LOCO, IT WILL DESTROY THE MOTOR.

Otherwise, H&M Controllers are ok. If in doubt, get your Controller checked by a qualified electrician, s/he will be cheaper than a new loco , or worst case, new residence !

Regards to All, Tumut.

[GrumpyPenguin]

1 hour ago, Tumut said:

HelloAll, regarding H&M Controllers with a Full Wave and a Half Wave Switch, UNDER NO CIRCUMSTANCES USE HALF WAVE ON A MODERN LOCO, IT WILL DESTROY THE MOTOR.

Otherwise, H&M Controllers are ok. If in doubt, get your Controller checked by a qualified electrician, s/he will be cheaper than a new loco , or worst case, new residence !

Regards to All, Tumut.

Many "qualified electricians"** are not too familier with extra low votage systems & the effects old controllers can have on modern motors and electronics.

 

H & M Controllers were good in their day, when most of us were using XO4's but unless you have a vintage layout & locomotives to suit then they are best replaced.

As it happens, most "H & M era" controllers fail PA Testing (well, they do when I test them).

 

** I've met quite a few over the years.

[spamcan61]

Given the 24V peaks and low pulse repetition frequency as I measured in the past, I wouldn't let my Duette near any 'modern' locos, particulasrly coreless.

 

 

Edited August 23 by spamcan61

[kevinlms]

On 23/08/2024 at 17:42, Tumut said:

HelloAll, regarding H&M Controllers with a Full Wave and a Half Wave Switch, UNDER NO CIRCUMSTANCES USE HALF WAVE ON A MODERN LOCO, IT WILL DESTROY THE MOTOR.

Otherwise, H&M Controllers are ok. If in doubt, get your Controller checked by a qualified electrician, s/he will be cheaper than a new loco , or worst case, new residence !

Regards to All, Tumut.

Actually 'Test & Tag' has no relevance for proper control of modern motors.

 

Testing of old controllers (in this instance H&M type controllers) has no bearing on the suitability of usage on such models. Testing, is all about whether or not they pass the ELECTRICAL safety test.

 

Fact is today, I could pass your H&M* (lets not go down the 'does it contain asbestos discussion' now!) but the next day, you try it on your brand new loco and you will probably find that it performs very poorly and find that it runs too fast at minimum settings at best.

At worst, the motor will die, but you hopefully won't have got to that stage, because you took it off the track, as the running was that bad!

 

* Some Duette style controllers will work better on modern motors than others. The reason is because the wire wound mat, came in 6 different resistance ratings. As per the attached catalogue page, probably the 'High' or 'Extra High', versions would give better results.

I don't have any to test, but I believe that there is no visable way of checking what version is fitted (colour code or number, for instance), but a multimeter would soon reveal the answer. DO NOT test with power on!

 

 

 

[DCB]

On 17/02/2024 at 18:10, markwilson said:

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!

 

Great controller, I have one but not as good as an H&M Safety Minor for X04 types due to lack of half wave.  Half wave is essential for running slowly down gradients with heavy trains with an X04.  Too many amps and not a quick enough cut out for Hornby Dublo .   The Vector's advantage is feather light hand held controls, screws so you can take it apart  and voltage controllable down to 0.1 volts, (H&M typically 5 volts minimum,)  Achilies's eels  Polyfuse cut outs, and no off position,  it jut goes from positive to negative with no break  Its a big shame they don't seem to do the single unit anymore