current overload protection for portescap motor ?

[Brit70053]

Some 35 plus years ago I put a Portescap motor into a DJH Standard class 5 model I built. Its the only example of this motor + gearbox I've used, having moved on first to Mashima plus DJH, then to Mashima plus High Level for subsequent kit builds.

I recall there being cautionary advice on the Portescap motor information leaflet about wiring in a circuit of 4 resistors(?) or similar to prevent, I think, current overload to the motor. Correctly or otherwise I'll call this the 'overload circuit' .

Last week the motor failed, but experimenting, I've managed to get it running out of the model and gearbox. The wiring on the overload circuit however came adrift when being removed from the loco boiler and when I've tried to re connect it no power is getting to the motor. My guess is I've wired it incorrectly and apart from the above, now vague memories, I can't recall much more about it.

 

Can anyone please either provide me with a copy of the appropriate circuit diagram, or advise me if it should be safe to run the motor under load without this complication ? My transformers/ power units are Gaugemaster 12 volt DC analogue. I also have Gaugemaster HF  track cleaners in use on the layout, but would readily remove them if they could present a problem when using this motor.

 

Many thanks for any information or advice anyone can provide.

 

Regards,

 

                  John

[Black5]

Hi John, I have the circuit diagram in relation to a Portescap RG 4 motor. It`s a very basic outline and may not be what you want. I can take a picture on my phone , but I need to figure out how load it to be able to send it , not having used this new system before. Let me know if it might be any use to you.

 

Jim.

[Brit70053]

Hello Jim (Black5), many thanks for your reply. It would be absolutely brilliant if you can manage to download/ upload/ attach (whichever applies) a photo of the diagram.

 

If you aren't able to do so, perhaps you could tell me from the diagram if the resistors (if that is what they are ?) are wired across both poles of the motor, or if the whole assembly just feeds from one of the input wires which has all 4 accessories in a circuit ?

 

Thanks again in anticipation of your further post.

 

John

 

 

Edited August 30, 2019 by Brit70053
spelling error

[Black5]

High John,

I`ve sent the picture as a PDF. Hopefully it`s arrived at your end and it`s of some use to you. Let me know if there`s a problem.

 

Cheers,

 

Jim.

RG4.pdf

[Brit70053]

Jim, That is exactly what I needed thank you very much. The diagram figure 2 matches what I extracted from the loco and shows the appropriate connection to one pole of the motor only, - the part I could not be sure of.

Hopefully I can now re install motor, gearbox and resistors correctly assembled.

 

Many thanks for your time and trouble, much appreciated.

 

                                                                      John

[Black5]

Pleased to be able to help John. Best of luck with your re-installation. I have a portescap in my scratchbuilt Duchess that`s going to get a Zimmo decoder in it. Like yours, my loco and motor are both 40 yrs old.

 

Cheers,

Jim.

[DCB]

Looks like 2 X 1 amp diodes in series.   I would have thought it would just keep the max voltage down a bit, 1 x diode is reckoned to drop voltage around 0.7 volts.   I think I would consider a fuse as recommended for the controller feed on board the loco, I'm not sure if polyswitches are available down in those ratings but the gradual reduction in power and "Resetting" when load removed should be ideal for on board fusing.

[Brit70053]

Thanks again Jim, it will be everything crossed for the re installation, but at least with the diagram you provided I'm now sure I'll get the wiring correct.

Good luck with your move to DCC, I hope the Portescap won't object, having run for so long (on analogue?) in your Duchess.

 

Thanks for the technical  elaboration about the components David, Its such a long time since I did the original circuit and to be honest I never had a great understanding of this type of electrical item.  Looking at my assembly, I'm a bit surprised that I seem to have put it together quite well using a piece of printed circuit board. I had no distinct memory of adding this in the motor circuit when I removed it from the model to investigate the motor.

I will however investigate the possibility of adding a fuse if I can progress to running the motor/ gearbox under load (in the loco) successfully.

 

                        Regards,

 

                                       John

Edited August 31, 2019 by Brit70053
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