Erattic running Hornby Castle .

[Sidecar Racer]

Hi all ,

 

just taken delivery of a Hornby Castle , not the latest all singing one but the older model , can motor and DCC

ready , it's one of the ones that have been split from packs , so no box .

 

When it was put on the track it ran like the proverbial bag of fretilizer , not to bad forwards but jerky and lumpy in

reverse , very much like a bad quartering problem .

 

A quick strip and a spot of lube , release the motor and check the running by pushing along , runs sweetly , back on the track

same as before , put up the rollers and given a very good run in both directions and seemed to be running fine , back on the track ,

no different , by now i'm starting to get a bit miffed .

 

All these test were done with a Kent Panel Controls feedback controller that runs all my other loco's with no problem , out of curiosity

I swapped this for an Orbit Supertroller , again a feed back type , this time I had a vast improvement in the running , very smooth in

both directions , then it started to play up , a runnaway situation developed even with the controller wound back and the direction

switch in the off position , next test was with an older H & M standard type unit , amazing result , perfect running in both directions

and good control .

 

So the question is , has anyone any idea what could be causing the problem when using a feedback controller ???

 

Could the capacitor across the motor be a possibility ? As stated earlier all my other loco's are okay , but most do not have the

capicitor as they are either kit built or of a much older vintage so may be more tolerant of controller , a Hornby 2800 tender drive runs okay as do most of the other older RTR ones .

 

Any thoughts and ideas will be most welcome , thanks for reading this far , and thanks in advance for any feedback .

[PWSlack]

The problem isn't the loco. It isn't the controller either. It's the combination of the two used together.

 

The motor may well be a modern low-inertia type, and it's these that feedback controllers have difficulty controlling.

 

A feedback controller tries to keep the motor speed constant by varying the width of the pulses of rectified DC it is sending to the motor. In the space between the pulses it measures the speed of the motor, by looking at its back-EMF, and decides by how much to vary the width of the next few pulses; if the motor is slowing, it will lengthen the pulse, and vice-versa. The problem with low inertia motors is that they respond to smaller numbers of pulses than the larger ones do, and in so doing thy have accelerated before the controller can work out what to do next. The same thing might happen if someone who is used to driving articulated trucks is put behind the accelerator of a Ferrari Enzo.

 

The simplest solution is to wire a resistance across the motor at some point. The most attractive of the simple solutions for steam engines is a grain-of-wheat-bulb in the firebox to give the impression of a loco working harder as speed rises. For diesels, well, one possibility is a smaller motor connected to a flywheel and a fan to give the impression of a turbocharger, perhaps, or possibly a light in the headcode box were one to be fitted. There are many ways to skin this proverbial cat!

[Sidecar Racer]

The simplest solution is to wire a resistance across the motor at some point. The most attractive of the simple solutions for steam engines is a grain-of-wheat-bulb in the firebox to give the impression of a loco working harder as speed rises.

 

Thanks for the suggestion , I tried a quick test by wireing a small bulb across the track , this did improve the forward running to some

extent but the reverse running was not really any better . I will have to try some other tests with the feedback units , I'm pretty well stuck with usung them as they are already wired into a large layout to be assembled .

 

Thanks again .

[Donw]

I would agree with PWslack about the controllers. Perhaps the mechanism is slighty stiffer or looser in reverse and the problem is greater then. Try different resistances and see if that works.

Don

[Sidecar Racer]

Thanks for your comments Don , I have been playing around some more and have found that the Orbit unit now runs the loco

smoothly in both directions . I did have both controllers wired from a common 16v supply , but only one connected to the track ,

the other was terminasted in a pair of crocodile clips for off track checks . Maybe there was a feedthrough problem even though

each one was switched off while using the other .

 

Certainly looks like the KPC unit is the problem . The Orbit when it was first introduced was said to be specially suited to Portescap

motors which it was said at the time should not be used with feedback . It certainly worked with the couple of motoers I had .

 

I will try again with a bigger resistance across the track to see what happens .

[Opelsi]

Hoping someone can help - just got a Hornby Caerphilly Castle.

 

Tested chip (Gaugemaster 26) which is fine on my ESU decoder tester and programmed it on said tester.

 

Fitted chip to the loco, the loco runs fast even when not selected on my ECoS. Just goes as soon as the power is on.

 

Has a trawl on here but not found anything - anyone know of any wiring issues with this model?

 

Thanks - Si

[CourthsVeil]

Si,

may I remind you: this sub-forum is named "Electrics (Non-DCC)".

You sure will get better response in the DCC-section of RMWeb.

   Armin