Advice, please, with a stuttering Class 37 TTS

[A Train, in a Garage In S]

Preface: I have been trying, in vain, to search existing forum threads for this problem. Therefore, it would be kind if more experienced forum users appreciate I am a new-to-forum-thread usage.

After running-in, in accordance with the suggested notes supplied with the new Loco (30 mins forward and 30 mins reverse) the loco, whilst running slow and fast, appears to have a stuttering movement.

The product details are:

RAILROAD PLUS - ENHANCED LIVERY

R30041TTS

COLAS CLASS 37 Co-Co

No.37421

(WITH SOUND)

The motor type, is one I have not seen before however, it appears to be of similar shape to a Ringfield motor.

Thanks

Gary

Moderators note - Title amended to add TTS and post moved to DCC section.

[96RAF]

The forum search facility is dire. Less is more when asking. ‘Class 37’ will get you more than ‘a long question’.

Odd that a new design loco would have a ring-field type motor, not something I have ever seen, any chance of some photos. Normally a recent Railroad model will have a single motor bogie with a can motor encased in a plastic housing that supports the gear train.

A factory fit TTS loco should be tuned for decent running out of the box, else adjust CV150 to value 1 and see if it improves things.

Early ring-field motored loco.

Later can motored loco.

[A Train, in a Garage In S]

Thank you so much for your reply. The diagram, you attached, answers the query regarding motor type - the first I recognise as a Ringfield and, the second, I believe, is the one fitted in mine. This is the first loco I have with this type of motor fitted.

I will certainly follow your suggestion, with regard to the CV setting and, see if that improves things. I have also taken on board your suggestion regarding short questions in the 'topic' when searching.

[A Train, in a Garage In S]

Your sound advice, regarding the CV, was the perfect 'fix' for the shuttering movement. As a novice when it comes to DCC CV workings, when I adjust the acceleration CV 4, will the adjustment I have made to CV 150, be affected?

[A Train, in a Garage In S]

(senior moment alert!)

CV 3 - not CV 4

[96RAF]

CVs in general act independently. CV3 has no bearing on CV150.

For a TTS decoder CVs 3 and 4 are set at a default value of 15 to allow certain sounds to play out before a loco moves off. These CVs affect the rate at which a loco accelerates or decelerates, i.e. its inertia. If say you set them at very high values >100 then the loco would take forever to get up to speed and also to stop. A value of zero would make stops and starts instant.

CV150 alters the basic characteristics that drive motor response.

[Fishmanoz]

The critical info here for a successful forum search is TTS and stuttering. The need to change CV150 Motor Algorithm has been covered previously on numerous occasions both for the algorithm itself and the two associated P and I CVs for finer control on each algorithm.

PS. Mods, can I suggest adding TTS to the end of the title and moving the thread to the DCC forum.

[A Train, in a Garage In S]

The critical info here for a successful forum search is TTS and stuttering. The need to change CV150 Motor Algorithm has been covered previously on numerous occasions both for the algorithm itself and the two associated P and I CVs for finer control on each algorithm.

PS. Mods, can I suggest adding TTS to the end of the title and moving the thread to the DCC forum.

Thanks for the updated info. As a CV beginner, can you tell me what ‘P’ and ‘I’ are referring to please? Not quite up to down yet with the hobby jargonese. Cheers G.

[Jupiter 1707822591]

Google "pid controller" this goes a long way in explaining how it works.

Basically has any device controlled by pid , as the limit ( this can be speed or temperature) is approached the controller begins to reduce the power supplied.then the controller can pulse the power needed to reach the Setpoint if the pid is set correct it will prevent an excessive overshoot of speed/ temperature

The fly in the ointment is the bemf of DC motors which can be jerky at the start and stop .which is what you are seeing

[Fishmanoz]

Once you have the PID info, just keep in mind, the first order adjustment is to P, the second order is I and the third D, but D is not used here.

Then also remember you only need to adjust P and I if the basic algorithm change doesn’t fix your problem fully and you’d like to refine the adjustment.