New Railway Modellers Forums

For fifty odd years manufactureres have been burdening us with all this paraphenalia attached to the inputs to our motors. Some chokes are fancy like on Bachmann installations and others are rather crude as in the old Triang fittings. Apart from the 'legal requirements' of interference suppression with the capacitor (plays havoc with DCC installations), what exactly is the purpose of the inductor/chokes fitted to our motors? Are they really necessary? In my years of modelling both 'h.o.' and largescale, one never came across these installations (except for Bachmann which in a feverish waste of energy, fitted chokes/capacitors to all their largescale 'Spectrum' locomotives and Thomas range locomotives).

Can they be removed and will it impact on operation, say with the old Triang motor?

Tim

Removing the RFI suppression components won't adversely affect the operation of a motor, in fact if it's on the old side it could conceivably improve it. You are only required to take reasonable steps to prevent interference from affecting a system with an efficient aerial, appropriate to its location. If you don't cause interference on your own TV/radios then unless you live in a very thin walled block of flats you are unlikely to interfere with anyone else's.
Cases of interference all but disappeared in the mid sixties with the shift from VHF to UHF for TV. The low powered digital transmissions were far more susceptible to RFI but now that switchover is completed there should again be very few situations where there's a problem. For anyone suffering from RFI don't bother reporting it if you haven't got the recommended outdoor aerial for your location!

I believe suppression is a legal requirement in the EU.

Tim

Reduction of RFI is a global requirement. The detail of what precisely is mandated in any given state varies somewhat, but the general principle is to limit emissions as much as is practical from what we might call 'serious' equipment. Design of electronics to reject interference has improved dramatically since they became part of everyday life. Regarding small scale trains in the UK, the 'old problem' of interference to AM radio and analogue television signals is now largely a thing of the past. 'Everybody' uses digital television signal streams which reject such interference very robustly, and AM radio is a minority thing.

GWR_fan wrote:Can they be removed and will it impact on operation, say with the old Triang motor?

I think the answer to this is "yes, if it doesn't cause an increase in RFI at its operating location". If you buy a S/H item which has had it removed, or you build your own, then you should check to see if it's absence causes any problems. Remember that directly received radio signals follow the inverse square rule so the test of it not affecting your own installation is a very good starting point. When the RFI investigations were handled by GPO engineers I was in the same office block as the local inspectors. They told some tales of horror of the standard of equipment that some complainants expected to give them good reception. By their reckoning model railways came a poor second to radio amateurs and in the vast majority of cases the problem was solved by fitting a half decent aerial, in some cases merely moving the set top aerial to the loft was enough. They referred to these as "coathanger cases." Nearly all of their problem cases came from two way radio base stations, and were usually cured by improving the transmitting aerial and turning down the gain.

I live approximately 150 metres from an amateur 'ham' radio operator. It must be a sizable installation as the aerial rivals that almost of a commercial radio station. Some fifteen years ago, I observed that every afternoon, my digital television reception would become distorted, almost on cue, at 2.30 pm. The disturbance would only last a minute or two. When I queeried about this I was told to look for anything nearby that may cause the disturbance. I put it down to the amateur radio operation in possibly the operator simply turning on his equipment. Digital television was then in its infancy out here and possibly not as resistant to interference as it is today. These days interference on digital reception is very infrequent.

Tim

Removing the suppression components may not be a good idea. Apart from the possibility of causing radio interference, which can affect all types of radio equipment eg wireless routers, video senders. TVs, radios etc, there can be an increase in the amount of sparking at the commutator of the motor. I remember, many years ago, running my old Triang jinty without suppression and the amount of sparking increased enormously and the brushes and comm' got very hot quite quickly.

Doh! wheres the edit button?

I meant to write "Triang Nellie" not "Triang jinty"