Loc motor capacitors

An area we all have problems with at some point. Don't be neutral, come on in to this lively forum where everyone is down to earth...

Loc motor capacitors

Postby jonnyb522 » 13 Jan 2010 23:48

Hello
Iam attempting to rebuild and convert a old hornby class 101 dmu (dated 1970s)to dcc control.
Does anyone have any useful tips?
Does the capacitor across the brushes need to be fitted? if so what is the rating?
In the wiring loom there is a suppressor fitted what is this component and rating?

I would appreciate any help

JB
jonnyb522
 
Posts: 5
Joined: 13 Jan 2010 23:33

Re: Loc motor capacitors

Postby Flashbang » 14 Jan 2010 10:07

Hi
Firstly, old ringfield motors are notoriously poor performers but are long lasting. So you really need to be 100% sure the loco and motor run faultlessly on dc power before considering converting it to DCC.
If it is at all hesitant or fails to start etc then don't even consider it for conversion. It will become much worse on DCC! You should be able to get a new replacement motor??

If it runs smoothly then go ahead.

The radio interference suppressor (RF capacitor) fitted across the two motor brush strips is not needed for DCC operation and can be removed.

Are you sure the other item is an in-line suppressor? I doubt it. The suppressor capacitor is across the motor brushes. What you have may be an inductor or a resistor. If its not in any directional lighting (If lighting is fitted?) and its in the feed line to the motor from the wheel pick-ups I would remove it for DCC operation. But if its in the lighting supply then leave it.

Once all the wires are removed from the two motor brush strips YOU MUST test each strip in turn to all the power bogie wheels and the metal chassis of the motor bogie to ensure there is no connection. If clear proceed with the DCC conversion. If a short is revealed (particularly on the left-hand strip to wheels or chassis) the cause MUST be removed before you progress any further. Often this is either a little protruding tab touching from metal chassis to a tab on the strip or the left-hand strips fixing screw needs insulating from the strip itself.

The chosen decoder needs to have a fairly large normal motor current output, so dont use the Hornby R8249 (500ma rated). So look carefully at what's available. I use and recommend TCS decoders which will work well with older motors or look at the Digitrax and Lenz range too.

A photo would help with the final verdict for the in-line item? :)
Best wishes with your railway modelling.
Broken? It was working when I left it!
User avatar
Flashbang
 
Posts: 455
Joined: 21 Oct 2009 18:22
Location: South of the Thames. UK

Re: Loc motor capacitors

Postby jonnyb522 » 14 Jan 2010 14:43

Thanks for your help

I will rebuild as a dc first and test,
The motor in the power bogie R157 is not the ring field type but is listed as a X112
However I would be interested in where I could get new motors
The component Iam talking about is on the service sheet is the one on the end of the x217 arrow. And is labelled as a TV. suppressor(Tried to add photo- failed )
The model does have directional lights on the top name plate
jonnyb522
 
Posts: 5
Joined: 13 Jan 2010 23:33

Re: Loc motor capacitors

Postby Flashbang » 14 Jan 2010 15:17

Hi again
I see what you mean now...Thought it would be a Ringfield, but its not as its much older! So ignore the previous advice! Sorry! :oops: :oops:
I see the item you're referring to - X217 or X216. They should not be used for DCC.
Commence by removing all wires from the motor brushes and chassis.
There must not be any connection what-so-ever between the motors chassis to either of the two brushes - see text below re insulating the V spring. Check the brush gear return spring (S3121) is not allowing any connection to the brushes!
Now wire directly from the pick up wire end (where the suppressor was cut off) to the decoders red wire and then the black decoders wire connects to the chassis - normally its easier to fit it under the screw that holds the V spring in place! But you might be able to use the former lighting connection screw too?
There shouldn't be anything else in the circuit.
Then wire the Orange and Grey wires directly to the two motor brush connections. You will need to place a piece of insulation sleeving on both sides of the V spring under the brushes top (there should already be one on one side anyway!) The spring keeps the brushes under tension onto the comm. Ideally solder the orange and grey decoder wires directly to the tops of the brushes, or use one (or two if you have them) of the little shaped push in connectors with the decoder wires soldered to them and they are then pushed in along side the brushes top part and held by the now fully insulated V spring.
If the loco runs the opposite way from the direction set on the console, reverse the Orange and Grey motor wires.

Having previously removed all lighting wires from the motor connections and chassis. You can now use the decoders White wire together with the common Blue wire for the directional lighting (Blue is common positive). 'F0' will turn on/off the light. The light will be automatically extinguished when running in reverse. If there is another light at the rear use the Yellow decoder wire with the common Blue to feed that.
The other alternative is to use the green decoder wire (on a 3 or 4 function decoder) and the blue wire. Then 'F1' will operate the light but its wont automatically turn off on direction change.

Insulate all in-line soldered joints ideally with some heat shrink tubing placed onto the wire before twisting together and soldering the joint. Then once the soldered joint has cooled, slide the tubing over the soldered joint so as it covers the joint and some of the wire insulation at both ends of the joint and then shrink it down with the aid of the soldering irons hot tip. :D

Service sheet link....http://www.modeltrains.net.au/hornby/service_sheet_details.asp?sheetid=166
Best wishes with your railway modelling.
Broken? It was working when I left it!
User avatar
Flashbang
 
Posts: 455
Joined: 21 Oct 2009 18:22
Location: South of the Thames. UK

Re: Loc motor capacitors

Postby jonnyb522 » 17 Feb 2010 22:59

Hello
Its been a while but I have finally managed to attempt the conversion but not much success :(
First I rebuilt it as DC and it ran around sweet as a nut with no stutter and good speed control.
Installed the DCC chip with red wire to pickups , black wire to body , orange and grey direct to the motor brush. Now other components.
I used a TCS T1 chip.
On the first run it ran very well with good slow speed control, however when I tried it the next night the motor would not run, the motor was buzzing with occasional slow spin but would not run properly. Checked for circuit with meter all correct
Any ideas ?
New motor brush, any additional components.
:?:
jonnyb522
 
Posts: 5
Joined: 13 Jan 2010 23:33

Re: Loc motor capacitors

Postby Flashbang » 18 Feb 2010 10:07

HI
You can try altering CV2 and CV6 values.
CV2 is the start voltage, which controls what the motor receives voltage wise at speed step 1.
Suggestion.... you start at a value of say 50 and try upwards by adding units of 10 and if necessary go below 50, again in units of 10. e.g 50, 60, 70 etc and if too fierce at 50 then reduce to 40, 30, 20 etc Note; you can try 'fine tuning' once the major 'Ten' unit is determined, by using values between the tens e.g. 25 or 38 etc.)

CV6 is the mid range voltage area and determines how the motor will perform after starting and before reaching the top voltage setting which is controlled by CV5.

Make a note of each CVs settings value as you change them, then you can easily revert to a previous (better) setting if need be.
Best wishes with your railway modelling.
Broken? It was working when I left it!
User avatar
Flashbang
 
Posts: 455
Joined: 21 Oct 2009 18:22
Location: South of the Thames. UK

Re: Loc motor capacitors

Postby jonnyb522 » 12 Mar 2010 23:26

The final chapter, Maybe!!
Well I went for a replacement of the motor brushes which I purchased from the bay, And had a play with the CV valves. It worked the train ran sweet as a nut with excellent slow speed control. I tested over a couple of day and all was good.
Then I wired up the light,its a mini filament type, and I think this managed to fry the chip I think, then I read the instruction and the function only have 100mA I think a filament bulb is more than this.[url][/url]
Any way will buy a new chip. Unless I can send the fried one to the USA
Anyone tried this?
jonnyb522
 
Posts: 5
Joined: 13 Jan 2010 23:33

Re: Loc motor capacitors

Postby Flashbang » 13 Mar 2010 10:49

Hi
Depends on the Decoders make?
If its a TCS it comes with a years 'Goof Proof' warranty. So no matter what caused the failure they will repalce it.
Other makes will depend on the manufactures literature statements re warrant!

You can obtain decoder with larger function current ratings - some are 250millamps each!

Good luck anyway :D
Best wishes with your railway modelling.
Broken? It was working when I left it!
User avatar
Flashbang
 
Posts: 455
Joined: 21 Oct 2009 18:22
Location: South of the Thames. UK

Re: Loc motor capacitors

Postby Son of Triangman » 01 Apr 2010 07:27

A word of caution about DCC and removing RF capcitors to imporve running. One thing to bear in mind when removing the supression RF capacitor for DCC running is that you will be breaking the TV interferance laws. If it inteferes with your neighbours telly and he reports the problem, you could be in for a very hefty fine.
Son of Triangman
 
Posts: 195
Joined: 31 Mar 2010 13:22


Return to Electrical & Electronics

Who is online

Users browsing this forum: No registered users and 1 guest

cron