Triang R751 D6830 powering problem --

QUOTE (flygopher @ 31 Dec 2007, 04:28) <{POST_SNAPBACK}>I have obtained an old Triang R751 Class 37 D6830 Diesel Locomotive. But it doesn't seem to like
my hornby R921 power controller (12v). It runs very slow and is really struggling to pass points.
I tried my other locos made by hornby with no problem at all. For example, I have a LMS Coronation
class 7P 4-6-2 Duchess of Sutherland and a B12 4-6-2 stream loco. Both of them run well with R921.
It happened I have borrowed a professional digital power supply (0-30V 2A output) from our electronic
department. I tested the loco with no problem. I set up the voltage to 12v and the D6830 runs very well.
The current was some 0.58A.

I really need some experts's help. Because I don't have any access to a Triang power controller, I have no
idea about their technical data. I was told they were on a 16v or 14v output rather than new standard of 12v.
Is this the cause of the fighting between my D6830 and R921? I read a story somewhere in the net
saying that some people changed the capacitator of their old Triang so they can use a newer Hornby power to
run their Triang trains. Is that true? If so, what is the type or volumn of the capacitator I am looking for to
replace the old one (which looks quite small but with no mark at all) in my D6830 .
Or if there is any other way of doing it.

I guess not only me with a Triang loco and a newer Hornby power have this problem. One of my friends has the
same problem of running his old Triang Princess class in a new Hornby R921 power controller. Hopefully
there are some experts can answer our questions and help us out. Many thanks!

Basically older motors are a little less efficient and draw more current, so if an older loco and a new one are run on the same track at the at the same time on DC, the newer more efficient motor will run much faster then the old. This can never really be overcome as far as "double heading" is concerned unless you add resistance to the newer loco to reduce its efficiency to the same level as the older one - however it should be possible to get the older loco to run better by itsself.

Try this to improve the "older" loco.

Remove the capacitor completely - just snip it off without cutting the leads its attached to. Its not really needed as far as the motor is concerned anyway.

Strip the motor down - if its a standard flat pancake type take the face plate off and clean it, remove the armature and clean it of all oil (lots of detergent and a soft brush, a good rinse and a good air drying). Clean out the motor bogie frame thats left, removing all gumk and old oil.

(don't remove the magnets by the way)

Clean out the slots in the motor commutator carefully with a sharp toothpick (they'll be full of carbon from the brushes).

Clean the commutators copper face as well as you can with a cotton bud soaked in thinners or alcohol. Be careful if you use thinners as plastics don't like them.

If you have some some super fine wet and dry it can be used to polish the face of the commutator until it shines like a mirror. Use 1200grit or better glued to an ice lolly stich for this, and be gentle and "even" in pressure. Polishing the armature face evenly will improve the efficiency of the motor a lot.

Take the brushes from the motor and give them a good clean - soak in meths for a while and then give them a good clean with detergent - let dry totally (overnight in a warm place).

add a tiny drop of oil (TINY) to all bearings, use graphite behind any plastic gears on the pancake motor OR a very thin/minimal wipe of teflon based grease (NOT OIL - this doesn't really help with plastic and can actually add to drag as it thickens with time)

Check the brush springs and make sure they are dead equal in length. Adjust if needed so spring pressure is equal on the brushes when assembled.

Reassemble and try it - it should be running a bit better.

TIP: Go to the fishing gear shop and get the oil and grease for fishing reels - the most commonly sold brand is "superlube" - this stays where its put and is long lasting - its also plastic compatible and not very dear - a tube of each will last forever.

Regards

Richard Johnson
DCCconcepts

Hi Richard, thank you very much indeed.
Happy New Year!
That's really really help.

In fact, I have done the procedures to almost all my locos.
The newer Hornby locos work much better. Espeically clearning the slots in the motor commutator
increased the performance of the Hornby locos significantly. My B12 runs madly now.

But sadly, the old Triang locos have not been enhanced for a great deal. They stull run slowly
like slugs. One thing I didn't make clear is that I only run one loco at a time. The old Triang locos
still do not like Hornby power R921 after thorough clearning. Removing the capacitator does not big difference
as well. I have measured the current. The D6830 loco consumes some 0.6A at 12V with a professional
power supply. The R921 claims it can supply up to 4VA. But the D6830 won't like it at all.
I guess there is something else in the loco needs to be fixed.

David, thanks a lot for very prompt reply.

That does solve my myth. Both my old Triang locos consume more than 0.6 A current from reading
of the professional power supply. Yes, 4VA is printed on the front of the R921 power supply.
So I guess either I am going to stick on the pro power supply (although it is big and heavy) or
to search for a more powerful power supply such as an old Triang.

Happy New Year!

I have suffered, and reported on, these sorts of problems from the past, regarding old Athearn and MDC locoos....and subsequent meltdown of modern controllers.

H&M controllers are excellent.

I had a Clipper once...still have one of their transformers..which HAS to be at least 50 years old now....and I bought it 2nd hand too......50 years ago...[1958]...plus a couple of their basic rheostat controllers.

They also did a unit with half wave rectification.......I believe it had a slide control as well as the roary spped knobby thingy.

Half wave was , at the time, the D's B's regarding slow speed control....even if it was a bit noisy and jerky by comparison with today's efforts.

The problems with rheostat voltage control [H&M] was in my mind, the STARTING voltage, no load.....the controller seemed to 'jump' straight to around 3 volts.

I tried wiring a car lightbulb in series.....but that only made the control area very hot!

and gave me a headache looking at it!