Rovex Princess Elizabeth 1951/52

[Davewill]

I have recently acquired a Rovex Princess Elizabeth circa 1951/52 ? - plunger type pick-up. This is the exact model I had when I was around ten years old, so it's nearly as old as me! The train is in good condition (even the carriage roofs) except for damage to the rear of the tender which I have repaired and made up a new coupling.

Despite a gentle clean and oiling (with 'proper' oil) the engine stops/starts and stalls. The track is from the fairly recent Rovex/Hornby Centenary Edition Princess Elizabeth set and I have tried two different basic controllers. I have just bought a Hornby HM2000 controller as this has a higher wattage output but I regret without the increase in performance which I had hoped for..

I am reluctant to play around with a seventy-year old motor. Has anyone any suggestions or should I just keep it as 'museum piece'. I note from various Youtube videos that some of these Princess's go well and others don't move at all.

Many thanks 

[ntpntpntp]

A couple of thoughts:
1) the plungers are the only pickups - the wheels are all plastic aren't they?   Therefore the track and plungers need to be scrupulously clean to stand any chance of sustained running. did it run ok with power applied directly to the plungers?
2) the track will need to be old stuff with a high rail profile otherwise flanges will run on the chairs?   I guess it needs Super 4, Series 3 or earlier track?  

Sadly the plunger Princess I was given some years ago was too far gone to resurrect, with a cracked body and wheels and other issues so it was discarded. 

Edited July 16 by ntpntpntp

[Davewill]

Thanks for replying so quickly - yes I cleaned the plungers with fine emery cloth and if you lift the engine slightly off the track the motor appears to run quite fast. I have seen mention of the problem with the flanges - I will see if I can procure some older track to try.

 

[Davewill]

Me again, a friend gave me some old track a few months ago; I sorted out the best sections to keep not thinking I would need them. Just tried the Princess Elizabeth on that track snd it goes better. I think the track and pickups need to be cleaned even after a few circuits but it is at least working. 

[What About The Bee]

Hi @Davewill

If you want to be certain it is chair interference with the flanges:

Place the locomotive on the track.  Without any power, gently push the locomotive forward.  Watch the front buffer. 

If the locomotive rises and falls, the wheels are encountering an obstruction.  Very likely the flanges to the chairs, which you can visually confirm.

When you do this under power, the wheels lift, breaking electrical contact with the rails.  And so it stops.

Bee

[Rana Temporia]

I have had a few of these and I think the plastic wheels have finer flanges than the later metal versions. The original track didn’t have any points and was a silvery grey colour and I believe only available in the set. It was different to the later grey ‘standard’ track. The brushes touch a circular commutator on the front of the motor and the running is different in reverse as the motor pulls away from the brushes. One of mine was running perfectly until the commutator disintegrated, it may have asbestos parts in it! I sold all I had bar one. 

I run my last one very infrequently as parts are not available very often and are usually in poor condition. Although it does work of a fashion it’s better as a museum piece if I’m honest. As you have noticed the rear wheels don’t make good contact and they struggle to pull the two shortie LMS coaches they came with. 

Early Grafar OO locos also had plunger pick-ups and some very odd motors which had similar running properties to the princess you have. The later Grafar locos were much better.

[Davewill]

That more or less sums it up; even with the tender attached the loco struggles. I think I will keep it just to remember my childhood. Years ago I almost bought some of the original track at a toy fair - long before I thought of locating the actual locomotive.

Thanks to all for your replies

 

 

 

[Davewill]

Update today - train now running on 'old' track and it pulls tender and the two original coaches, albeit on full power. Where would I be without the forum?

[Rana Temporia]

Looks like it also still has the front steps at least on one side, they are usually long gone and were moved onto the front bogie when a coupling was introduced. The coaches are pretty straight as well, although missing the buffers. Any off scrap early wagons or coaches will fit. 

[Davewill]

I understand that very old locos such as my Princess Elizabeth may benefit from/require higher power than more modern trains. If this is so would a Gaugemaster GMC-100MO with 2.5 amp output we a wise investment?

[Rana Temporia]

I think this originally came with a battery controller which would limit the available power, I can check tomorrow. Be aware of its age and the fact that the commutator and brushes aren’t easily replaceable or repairable and a lot of power might see them off permanently. My MK 2 motor disappeared in a plasma glow but luckily the armature was the same as an X04, not the case with your loco. 

2.5 Amps would probably shift an O gauge Garratt!

 

[Davewill]

Thanks for the advice. I am very aware that the motor is rather old and vulnerable to over-use; I will be running it only occasionally. The important thing is that I was able to find one in reasonable condition after a long search.

[What About The Bee]

Hi @Davewill

Preamble

I think the Rovex took two 6V 'lantern' batteries.

6-volt lantern batteries can have different amperage ratings, including 4.5 Ah, 5 Ah, and 11 Ah

Ampere hours (Ah) is a unit used to describe the number of amperes the battery can produce over a specific period, with the battery discharged to zero.

Two lantern batteries, wired in parallel does not increase the voltage but does increase the ampere hours. 

Two lantern batteries, wired in series, does double the voltage to 12v, but does not increase the ampere hours.

Discussion

Rovex trains run on 12 vdc.  No adjustment to ampere hour rating.

So, for a 10 hour period, from fully charged to flat, a pair of 5 Ah lantern batteries, wired in series, will supply 0.5 amps per hour, for each and every of the 10 hours.  This isn't quite perfect, as there will be a voltage drop over time.

Even if the 11 Ah lantern batteries are utilized, over a 10 hour period, that is still only 1.1 amps.

The amperes delivered halves if you choose a 20 hour discharge period OR doubles if you choose a 5 hour discharge period.

You could also drain the batteries in one hour, and deliver a whopping 11 amps. 

I think 10 or 20 hour period selection is quite a reasonable and practical selection, but your mileage may vary.  Further, the 5 Ah lantern battery the one used.

Conclusion

I would avoid the 2.5 ampere power supply, unless you intend to let all the magic smoke escape (burn the motor out).

The 1 ampere supply is plenty

Bee

Edited August 1 by What About The Bee

[Davewill]

I think my original Rovex (given to me in the early 1950s) was possibly second-hand as it did not have a battery box. Power was supplied by an accumulator (for the really young - that was like a glass car battery). Of course, my father being an engineer in an electrical company may have thought it was a cheaper option than buying batteries!

As regards the amps output, I must admit to a degree of confusion. I did a lot of research before deciding to replace the basic Hornby controller and a number of sources including at least two reputable suppliers said the GMC-100MO was entirely suitable for very old locos. (One was a Hattons Youtube review of various controllers)

I can only repeat what I said earlier; I will run the train sparingly

 

 

 

 

Edited August 1 by Davewill

[Rana Temporia]

If I get the chance over the weekend I can see how much current mine needs. I won’t try it with PWM controller as that might finish it off!

Tri-ang and especially Hornby Dublo locos needed more current than modern locos. At least one of the Tri-ang catalogues had an indication of how much current their locos needed. I have never had a problem with my Tri-ang and H&M controllers which provide plenty of power, and when I built some PWM units I got a 2A supply for them which is probably overkill. 

[Rana Temporia]

I just remembered that I had these that came unexpectedly with some Continental catalogues I bought years ago. My intention was to scan them and then ask a friendly local printer to clean up the scans and print me some decent ones for my loco and coaches. Unfortunately I don’t have the tender box. These are not in great condition.

[ntpntpntp]

Gaugemaster GM100MO is for O scale where you get heavy locos and stock needing a more powerful motor.    I'd have thought the old Rovex Princess motor is probably only going to want something like 500mA , maybe a bit more if heavily loaded?  Similar to a Hornby Dublo motor. 

[What About The Bee]

Hi Dave

The GMC-100MO is rated at 2.5 amperes.

My assessment is entirely based upon analysis, not first hand experience with a Rovex Princess.  Yet, it is a fairly straightforward analysis.

The Princess could run with an accumulator, batteries or a transformer.  Carefully now, the Princess internals did not change when using any of those sources.  As such, the analysis using batteries, provides us with some boundaries that will apply when selecting a power supply.

The unit that trips most people up is "Ampere Hours" (Ah).  This is related to, but not the same as amperes.  With amperes, you are describing a limitless measurement. Draw 1 amp today, tomorrow, next week, next year.  It is apparently limitless.  Switching to Ah, batteries are not limitless, they have a state of charge, from fully charged (new) to discharged (dead).  The 'h' in Ah is used to indicate the limited nature: hours.  As in 'how long to flat?'  

So.... Amperes [for this many] hours.  I hope that clears up the unit.  And that is how to translate it.   Simply divide the Ah by the expected number of hours and you get amperes.

The critical question is then, how many hours.  I used common sense, as your father did when he selected an accumulator, to pick a number of hours.  Somewhere above 10 hours.  So I conservatively picked 10 hours.  More hours reduces the amperes supplied. Anything less than 10 hours and parents would be plenty upset.  I have searched for the logical flaw in this discussion, and this may be the only spot.  The number of hours directly affects the solution.

I await Rana's measurement.

Bee 

 

Edited August 1 by What About The Bee

[What About The Bee]

There is one other very interesting data point, whilst we eagerly await Rana's measurement.  

Hornby Dublo was roughly from 1938 to 1963, right around the dates of Rovex Princess production. They would have used the commonly accepted OO standard.  The Hornby Dublo type 00/1 transformer had output fuses.  We discussed these awhile back.  There was some uncertainty over the rating, until an image of a box of fuses was found.

https://community.hornbyhobbies.com/forums/topic/34978-hornby-dublo-type-001-12v-transformer/?do=findComment&comment=371732

1 amp slow blow fuses.  Consistent with the battery analysis. 

Bee

[Davewill]

Not being an electrical expert no wonder I am confused!

This is the rear of the GMC-100MO box. Spec on web-site says 2.5 amp, box says 14v DC at 1 amp controlled.

[Going Spare]

Wrong box?  That is for the 100M, not an 100MO which has a higher output basically for 0-gauge motors.

Or is it - the main box printing says 100M but I think the label at bottom right says 100M for 0 gauge?

Does your controller have a din-plug socket or any output information on its case? 

Edited August 1 by Going Spare

[ntpntpntp]

So that list of specs is given for 3 different versions and seems to imply that for O gauge they up the max output voltage for the track by a couple of volts but still only 1 Amp.   

I was expecting the current limit on the O gauge version to be a bit higher.  Not as high as the LGB version (not mentioned on this box) which is 2.5 Amps at 20V on the track output, and I know some G scale modellers find the GM100LGB a bit under-powered.  Some of my G scale locos have 4 or 5 Amp decoders fitted 🙂 

To be honest I still expect that the 100MO will be perfectly fine for the Rovex motor. You don't want the overload cut-out to be too high or it won't give reasonable protection.

Edited August 1 by ntpntpntp

[Davewill]

The controller is an MO, as per the label on the actual unit. The din plug is M only I believe and is blanked out on my MO.

 

[Rana Temporia]

My partner is working so while she’s busy I have been up in the spiderfest and retrieved the loco. It wasn’t running forwards but a quick straightening of the con rod sorted that. Running like a new one now off the track but I can’t find the tender with the mk1 coupling for it. 

Running forwards light engine at a measured 16v from an old Tri-ang controller it drew 400mA, running in reverse it drew 350mA. An X04 fitted Tri-ang Nellie undergoing the same test drew 400mA in both directions. 

I don’t want to put it through much more of a test. I hope this is useful. 

[Davewill]

Just as a matter of interest I have looked at Pat Hammond's 'The Story of Rovex Vol 1 1950 - 1965', this is an extract from the section on motors.

Edited August 1 by Davewill