Manual Speed Control

Dr. Bond of the DVLR · Post by **Dr. Bond of the DVLR** » Tue Jul 21, 2009 4:01 pm

I am currently making a locolines tiny kit that I found from a couple of years ago for a friend. I should like to be able to controle the speed using a potentiometer and IP engineering sell a kit. I have all the components but a circuit diagram on how to wire up the potentiameter would be greatly appreciated! Two DPDT switches will also be encorporated for on/off and direction control!

Many thanks,

Um help someone??- Please!

Hancockshire · Post by **Hancockshire** » Sun Jul 26, 2009 5:34 pm

Here's a circuit diagram

The speed controller is actually a variable resistor (changes the flow of current). I'm not sure if it'll work but have a go.

mhlr · Post by **mhlr** » Sun Jul 26, 2009 11:49 pm

I actually sent him a diagram like that a while back. But he said hes done that, do you mean Bond; a diagram to show how to wire the pot. with a chip etc...?

Dr. Bond of the DVLR · Post by **Dr. Bond of the DVLR** » Mon Jul 27, 2009 10:33 am

No Pete- I have tried all that and have come to the conclusion that my Potentiometer has far too much resistance giving me a sort of off/on switch instead. Testing with a multimeter the motor has a resistance of about 2 ohms and I will be running it at 2.4 volts (2 AA rechargeables) therefore by introducing a resistor at 2 ohms you halve the speed of the motor, thus I need a potentiometer that has a range of 10 ohms to nearly 0 ohms resistance, a 10 ohm pot is rediculusly small- the one I had in stock was 1 K ohm! So I need to find one of a smaller value. I was wiring everything up correctly!

DLRdan · Post by **DLRdan** » Mon Jul 27, 2009 10:51 am

i know what you are trying to do, using just the pot to controll the speed it does work as i have done this with my jack and ive used a 10 ohm pot to do it. The down side it that the 10 ohm pot is nearly 4cm across

Dr. Bond of the DVLR · Post by **Dr. Bond of the DVLR** » Mon Jul 27, 2009 11:53 am

Right! So where did you get it from- also I beleive that IP sell there kit with a thermistor if you look in the picture- or it might be a transistor. This might be why their kit comes with a pot that looks identicle to the one I used and why I wondered if any one had one of there diagrams! Also how much does a 10 ohm pot cost??

DLRdan · Post by **DLRdan** » Mon Jul 27, 2009 1:46 pm

mine came out the loft from dads box of bits but after looking araound they are about £14

mhlr · Post by **mhlr** » Mon Jul 27, 2009 4:14 pm

Mr. Bond of the DVLR wrote:IP sell there kit with a thermistor if you look in the picture- or it might be a transistor??

Would not be a thermistor, that changes the resistance according to temperature. Definately a transistor.

New Haven Neil · Post by **New Haven Neil** » Tue Jul 28, 2009 1:53 pm

The IP transistor is actually 2 in one case, a 'darlington pair'.

The pot does not control the speed, it balances the electrical power which is less wasteful than shunting it off to be wasted as heat in the pot.

I have a diagram 'somewhere' if you need.......and the components can be bought from maplins for less than IP......

NHN

Dr. Bond of the DVLR · Post by **Dr. Bond of the DVLR** » Wed Jul 29, 2009 11:06 am

I have a diagram 'somewhere' if you need.......and the components can be bought from maplins for less than IP......

Many thanks! That would be most useful! I am trying to get this done before the 25th of September for a friend's birthday however I have started to become attached to my creation.....

New Haven Neil · Post by **New Haven Neil** » Wed Jul 29, 2009 1:13 pm

I'll have a scratch around tonight for it....it's 'somewhere' in the garage - which, if you had seen it, you would realise is a challenge!

It's a crib of the IP one anyway, dead easy to do, honest....

I'll try to find a components list too.

Crackingjob · Post by **Crackingjob** » Fri Jul 31, 2009 1:39 pm

Can I point you to the web site of cambrian...who do a series of controllers for both types of batteries ie gell and the other??!!
plus lots of other 'ittle bits and bobs'. The controllers can be bought pre made or as a kit (saving a few quid...the wife says pre made is worth the money saving the swearing and smell of burnt flesh/electrics) Ideal for the budget credit cruch engineer.
I can recommend....

http://www.cambrianmodels.co.uk/

Also recommend.....

http://www.timpdon.co.uk/timpdon/index.htm

and for those with a few more pennies (and expensive trains) the upmarket http://www.brianjones.free-online.co.uk/

All are very helpful and in the case of Mr Jones sells batteries,chargers etc and all will help taylor your rquirements.

If my links fail..look in the www.16mm.org site and go into Links and Resources and to the bottom of the page where you will find links to these and other traders
I have a few other diagrams i will post but add one i have which cuts out a set of batteries (drop voltage up amps i 'tink') You use two switches as opposed to speed pedo controller.

Crackingjob

Also as seen on 'Peda J' my camborne & Redruth Mineral Tram
ps I have fitted one into a Faller loco ..converted from 12v track to 9volt battery and into my vertical loco...also small in size

Happy electronics!!!!!

New Haven Neil · Post by **New Haven Neil** » Fri Jul 31, 2009 2:23 pm

H*ll, I forgot about this - I'll try to see to it this weekend for you!

Apols

Neil.

Dr. Bond of the DVLR · Post by **Dr. Bond of the DVLR** » Fri Jul 31, 2009 7:08 pm

many thanks!

New Haven Neil · Post by **New Haven Neil** » Mon Aug 10, 2009 8:55 pm

Ta daaaa, here it is - this is a blag from either Carl on the continental forum, or Neil Robinson on GSM, I don;t recall which, sorry guys.

Now, I see it doesn't have the values on...oh here we go again, another bit of paper I have lost.....I do however have several in use so can look at them!

To reverse, add in a dpdt switch like in the post above in the leads to the motor - NOT the input from the battery. If you do that, the magic smoke will be let out of the transistor.....and it won;t work any more......

Dr. Bond of the DVLR · Post by **Dr. Bond of the DVLR** » Tue Aug 11, 2009 11:49 am

Many thanks indeed, I'll get on with that when I get back from Wales!

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