Those 'horrible' electric (diesel) locomotives

[stantheman]

I am one of 'those' that built an electric (diesel outline) locomotive primarily to be used by my grandson until he was able to handle either of my steam locomotives. I ended up using four 24 volt motors run through one of the well known UK suppliers of controllers (Parkside). I did in the first instance purchase a sound unit to give it a little bit more credibility when running, but this turned out to be only suitable to use on 12 volt motors, being a unit that connected across any two motor feeds. It fairly quickly destroyed itself.
The suppliers, again a well know UK source, promised a 24 volt version 'sometime last summer' I am still waiting to hear from them.

Is there any chance anyone out there has details of such a unit or circuit diagrams, that could be used this summer. Time is marching on I understand, even though I still feel young!

Thanks. Stan.

[steam4ian]

G'day Stan

I understand you now have Jaycar in the UK and I think they mail order. They would certainly have a web site. In Oz they have 24/12V converters as kits and maybe as modules. Why not give them a try?

regards,
Ian

[stantheman]

Thanks for the info about Jaycar.
I have tried to find them in the UK and apparently they trade under the name Techstore. Will try to find out more about their products and see if they can help with the question of the sound units. Thanks again.
Stan.

[jackrae]

Apart from Parkside, the other well-known Uk amnufactirer is 4QD
Their website 4qd.co.uk contains an amzing amount of useful info and their prices are quite reasonable.
Regards
Jack

[JohnP]

Stan,

When you say the original unit "connected across the motor", is that the supply for the unit or (more likely) the circuit that senses the speed? It seems to me that you have two requirements, one to power the sound system off the 24V supply, and also to reduce the voltage coming off the motors.

Both should be fairly easy to do, although there may be complcations with reversing. Do you have a circuit diagram?

JohnP

[stantheman]

Hi John.
The sound producing unit had just two supply wires, these connected to any pair of the motor current supplies. The unit as a whole then obviously sensed the 'speed' and through the electronics produced the sound, which varied as speed built up and was reduced. The unit itself had a small amplifier and speaker, but I did disconnect that and passed it through a much bigger amplifier and suitable speaker. I did at one stage place a voltage regulator across the supply to the unit to limit that down to 12/14 max, it worked in some way but the speed of the 'sound' was still as though the unit was receiving 24v and not 12v. On start up it was almost a racing speed and quickly became almost one continuous 'pulse' as speed was increased. (All very mysterious). I do not have any circuit diagram for this unit. I am not really into any of these integrated circuits or any other come to that, so any 'technical' help would probably be lost on me. I did say in my first post about circuit diagrams, but maybe that was just wishful thinking on my part.

I do know about 4QD but that was not really my question.

Thanks anyway for the help so far to everybody.
Stan.

[Chris Kelland]

Hi Stan,

I run a pair of class 20 loco's with sound units in both. The sound units are from Trax Controls. Although they work from 12 volts use a feed from the battery that is closer to earth i.e. the +ve is at 12 v. above chassis. The speed feed is taken from the controller pot not the motor so only has a few millivolts at most, one end of the pot is at earth potential. Trax make 2 types, one to drive and external audio amp and the one you want with its own small o/p stage. Usual proviso's.

Regards,


Chris.

[Chris Kelland]

Hi again Stan,

Have a look at www.traxcontrols.com. No connection with Company other than a satisfied customer.

Chris.

[JohnP]

Stan,

I'd have thought you could have sensed the voltage through a potential divider - that's only two resistors, in this case probably equal and a couple of thousand ohms each would do - not critical - unless the unit derives its power from there too, in which case it would just not do anything. Did the unit have its own batteries?

JohnP

[peterseager]

I have a loco with the same set-up. You do not state the manufacturer of the sound card is but mine is made by Trax. See www.traxcontrols.com/ for information.

The Trax Printed Circuit Board (PCB) has 6 terminals. If you position the board with the preset controls at the bottom, there are two on the left and four on the right.

.........................................................3 Speaker +ve
1 +12V DC...........................................4 Speaker 0V
2 0V DC...............................................5 Speed A
........................................................ 6 Speed B

I assume you have two 12V batteries connected in series to give 24V. This gives three connection points, 0V, +12V and +24V.

The Parkside controller is connected to 0V and +24V via heavy wires terminated directly to the PCB inside the controller. The hand control unit, used to drive the loco, plugs into an 8 pin DIN socket on the controller.

Referring back to the sound card, connections are as follows:

Terminal 1 - +12V. This is connected to the +12V connection between the batteries via a switch and 1 amp fuse. If you are using 12V horns, the switch can be a 6A Miniature circuit breaker (MCB). The horn circuit may be fed directly from the MCB but the fuse is still needed for the sound card.

It is possible to install a 24V to 12V converter to drive the sound card. Maplin have a couple of suitable items in their catalogue (N62AW (pre-assembled module) and VE58N (kit)). Again this circuit should be fused.

Terminal 2 -0V. This is connected to the 0V battery point, preferably at the battery terminal. (A 24V to 12V converter would also have a 0V connection here).

Terminal 2 & 4 - Speaker. These connect to the loudspeaker. The loudspeaker must be mounted in a box for good results. Even better is a larger speaker. Again Maplin can supply these. I have a 5 1/4 inch speaker which is the biggest that will go into the 5inch gauge Hymek body. It is positioned facing forward under the cooling fan grill. I have found a thin piece of polythene from a freezer bag, taped across the top of the speaker box so that it hangs down loosely in front of the speaker, will protect the speaker from rain without degrading the sound. The sound output from the Trax card is adequate for normal use eg school fetes. If it were louder it would become annoying to the driver.

Terminals 5 & 6 - Speed. Terminals 5 and 6 connect to a diode bridge on the PCB and are intended to be connected to the track of a model railway layout where the 12V DC supply for the PCB is supplied from a transformer isolated supply. In the case of the model railway the sound card has to cater for forward and reverse. Our installation is completely different. In fact the PCB track to terminal 6 was burnt out when I bought my loco because this had not been appreciated. I recommend terminal 6 is left disconnected and let the speed control circuitry find its 0V via Terminal 1. This leaves us with terminal 5, which is I think the real nub of the question. This has to be connected to the connection between the speed control on the hand control unit and the controller. Forget trying to connect to the motors. That is chopped 24V variously switched to provide forward and reverse which gives the results stated in another post.

If you connect the hand controller directly to the controller, open the box of the Parkside controller you will find an orange connector inside connecting the DIN socket to the PCB. You need to connect a wire into the third pin from the end nearest the DIN socket. It will already have a blue wire in it. Connect the other end of the wire to Terminal 5 on the sound card. Best to drill a hole in the lid, it can be removed completely so that swarf is kept out of the controller. The Parkside hand controller outputs 0 to +24V for speed but the Trax sound card is designed to work with this. Speed is independent of the Forward and Reverse setting.

If you have provided a socket on the loco for the hand control and wired this to the controller you can connect Terminal 5 to the wire connecting pin 1 on the DIN connectors. As part of the current rebuild I have included an interface PCB between the loco socket and controller so that any of the control signals may be picked off easily.

The Hymek has undergone an internal rebuild this winter and now includes a 24V to 12V regulator. I have modified the sound card so that it now sounds as though the engine starts and stops rather than the abrupt stop provided by the standard card. I am also experimenting with a more powerful amplifier, not for engine sound but to add electronic horns. I am not impressed with the Trax horn module it does not sound right and only gives a fixed dee daa cycle when you trigger it. I currently use car horns. I have used Audacity to generate suitable tones on the computer, I just need to develop the hardware. When the existing horns go the connection to the 12V point will also go.

I hope this helps.

[stantheman]

Thanks to everyone for your replies and information, sorry for the delay in answering but have been away for a couple of days.

My own diesel sound card was in fact from Trax. It did state clearly that the connection should be across the motor feeds and was as stated designed for 12v operation. I have spoken with them and it was from there the idea of waiting for a 24v unit came. My amplfier is a unit from Maplin, which did the job very well combined with a larger speaker mounted on the floor of the loco facing downwards. All of the info that means taking the sound unit and altering the wiring sounds a little too far above what I want to do, but thanks anyway. I guess Trax will come up with the goods one day, they promise to let me, and a few hundred others, know when it is available.

Thanks again to everyone. Stan.