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9V/PF crossover?


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#1 Matt Dawson

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Posted 16 December 2009 - 09:29 PM

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Here would be a system that would allow the best of Power Functions and 9V - and no, not DCC (though similar).

As with 9V, the track is fed from a wall mounted transformer; however, this is just to provide a stable voltage - around 9.5V - which is roughly the voltage for PF. No controller would be between the transformer and the track.

The track is the same as 9V, except that special 'converter' pieces were available for loops etc., which would have a small, 5mm plastic rail section in the middle to allow a change-over in track polarity.

To power the trains, a motor, similar to the 9V one, would be available, though this one would feature a small flywheel. It would have a new 2x2 4 contact PF connector bit, which would connect to a new reciever. A 2x2 plate would be available to convert the motor for 9V use.

A new reciever, based on similar lines to the new one, would feature one normal and one new lead with 2x2 4 contact PF electrial comnnector, split into two pairs; 1 pair for track power collection, one pair as a motor feed. It would also feature a small 'detection' sub-circuit that would allow the detection of a polarity change, and alter the motor feed accordingly. If you needed to use/feature 2 motors, a duplicate trackfeed/motor socket would feature on the underside but not feature a lead - a special one with the new 2x2 4-piece plate connection would be available seperately.

So the benefits of this new system?

1. Track feed from the wall-mounted transformer would do away with the bulky battery,
2. Track feed would also allow for extra current collection if needed, for heavy loads, hills etc.
3. The motor is 9V compatable (depending if the 4 contact connector was of 9V or PF style, lights also), pleasing the train fans which needed new 9V motors.
4. The controller from the current PF range would still be usable with the new system.
5. Allows the return of 9V style track, which is another boon for the 9V community.

What are anyone's thoughts?
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#2 TaltosVT

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Posted 16 December 2009 - 11:55 PM

View PostMatt Dawson, on Dec 16 2009, 04:29 PM, said:

So the benefits of this new system?

1. Track feed from the wall-mounted transformer would do away with the bulky battery,
2. Track feed would also allow for extra current collection if needed, for heavy loads, hills etc.
3. The motor is 9V compatable (depending if the 4 contact connector was of 9V or PF style, lights also), pleasing the train fans which needed new 9V motors.
4. The controller from the current PF range would still be usable with the new system.
5. Allows the return of 9V style track, which is another boon for the 9V community.

What are anyone's thoughts?
This is possible today with available parts.  See the discussion on this Flickr group: http://www.flickr.co...57617947835040/

I found that it works well on a small layout, but when we tried it at the NMRA show in July, it didn't work as well.  I think the lighting conditions and distance played a large part in that.

Rather than trying to bring back 9v track at this point, which they won't do for multiple reasons that have been mentioned over the last couple of years, I'd rather see LEGO work on making a smaller battery.  The PF trains are powerful enough, the batteries they have available are just a bit larger than I'd like.

-Elroy

#3 Mark Bellis

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Posted 19 December 2009 - 05:27 PM

View PostTaltosVT, on Dec 16 2009, 11:55 PM, said:

This is possible today with available parts.  See the discussion on this Flickr group: http://www.flickr.co...57617947835040/

I found that it works well on a small layout, but when we tried it at the NMRA show in July, it didn't work as well.  I think the lighting conditions and distance played a large part in that.

Rather than trying to bring back 9v track at this point, which they won't do for multiple reasons that have been mentioned over the last couple of years, I'd rather see LEGO work on making a smaller battery.  The PF trains are powerful enough, the batteries they have available are just a bit larger than I'd like.

-Elroy

This circuit could help with IR control for large layouts and tunnels.  My idea was to put the IR LED in a tunnel so that there were no IR "not-spots" along the track.  The receiver would be visible to the operator but out of sight of the public at a show.

There's no reason why you couldn't use two IR receivers in parallel, as long as they received the same signal.  Also, use receivers per track section, with insulating tape at the rail joints.  That way you can use separate transformers to supply the power.

I'm working on hybrid 9V/PF trains, which would use the PF battery for the lights whilst running off 9V track but would be able to switch to battery power for the motors too, to go over double crossovers and other plastic track sections.  I have found a need to isolate the PF power from the 9V power because the 9V power attempts to charge the battery, drawing too much current!  I've added a relay circuit to solve this and it is working in the prototype, but is not ready to publish yet.

For the PF LiPo battery, we need more power in the smaller size - both attributes are limited by the technology!  Let's hope there's a new battery in 3 years' time, which has double the energy density (riding on the back of mobile phone and laptop battery technology!).
We also need faster charge time, though the charger puts out 700mA already.   Faster charging might not be possible due to child safety restrictions on the maximum voltage and current in a toy.
I hope we get inductive charging - a device that sits on top of a track piece (4x8 and 2 plates high with smooth top), making it look like a level crossing, containing coils, with a wire to a transformer that supplies a charging signal.  A 4x8 device containing another coil is slung under a wagon to pick up the charging current, with a wire going to the battery on the train.  Inductive charging mats are in the shops now, able to charge a phone or DVD player, so hopefully such a device for LEGO trains is not too far away.

Mark
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#4 Matt Dawson

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Posted 20 December 2009 - 06:55 PM

View PostMark Bellis, on Dec 19 2009, 05:27 PM, said:

For the PF LiPo battery, we need more power in the smaller size - both attributes are limited by the technology!  Let's hope there's a new battery in 3 years' time, which has double the energy density (riding on the back of mobile phone and laptop battery technology!).
We also need faster charge time, though the charger puts out 700mA already.   Faster charging might not be possible due to child safety restrictions on the maximum voltage and current in a toy.
I hope we get inductive charging - a device that sits on top of a track piece (4x8 and 2 plates high with smooth top), making it look like a level crossing, containing coils, with a wire to a transformer that supplies a charging signal.  A 4x8 device containing another coil is slung under a wagon to pick up the charging current, with a wire going to the battery on the train.  Inductive charging mats are in the shops now, able to charge a phone or DVD player, so hopefully such a device for LEGO trains is not too far away.

Mark

The main reason I suggested this crossover is to get rid of the need for batteries - it also means that one track supply could feed many trains - one battery can't...

However; there's nothing stating that you wouldn't do away with the battery all together; a similar arrangement is used on real electric trains - the 'battery' ensured that the motors kept turning until track power was regained. Theidea was also floated a couple fo years ago to enable electric freight locos to go onto un-electrified track to shunt a few wagons...
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#5 Ashi Valkoinen

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Posted 03 January 2010 - 02:48 PM

Trains powered from overhead wires, crossing 9V and PF - what do you think, could it work?

Below the image you can find some description:

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Step 1: Use 9V speed regulator and a piece of 9V track for electricity supply. Use copper wires and make it touch the metal piece of the 9V track. Then connect this wires with the overhead wire.
Step 2: We need a modified pantograph to get electricity from the overhead wires. The main problem is to separate the two wires to avoid short circuits.
Step 3: We need this time to modified a 9V extension wire to connect the 9V system and the overhead wires.
Step 4: We use this time the 9V-PF extension wire.
Step 5: Connect the PF IR reciever and the extension wire.
Step 6: this time we use a 9V-PF extension wire again...
Step 7: ...to connect the train motor to the PF-IR reciever.
Step 8: Turn the 9V speed regulator to maximum voltage, and use PF IR speed regulator to drive your train.

Advanteges  :thumbup:
-You don't need batteries (or the expensive rechergeable battery box) to supply your trains.
-9V system grants you power but you don't need lot of 9V track anymore - and you can controll train light and train speed separately.
-It seems more realistic to power your train from overhead wires.
-Using more 9V speed regulators and making more, separated track sections makes your display realistic.
Disadvanteges  :thumbdown:
-You need to mod a 9V extension wire.
-You don't use ony lego parts.
-It's hard to make wires above switches - but it's not impossible.
-I don't know, that system would work or not. :D

What do you think about this?
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#6 peterab

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Posted 05 January 2010 - 05:41 AM

View PostAshi Valkoinen, on Jan 4 2010, 01:48 AM, said:

Trains powered from overhead wires, crossing 9V and PF - what do you think, could it work?

What do you think about this?

It's an interesting idea, but I'd do it slightly differently.

In the protoype typicaly only one active overhead wire is used, and it would be easier to keep the connection between the train and wire solid in lego too. Unfortunately that would require 9V track for the earth, so negate most of the benifits of having a powered overhead wire anyway.

If I were to do this I'd do it purely for looks, and use the PF battery for power.

#7 Duq

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Posted 05 January 2010 - 08:15 AM

It's a nice idea but impossible to get to work.
If you do it like in the real world you still need metal track. It'll be difficult and possibly expensive to make the overhead wires.
Using the double overhead wires would make it even more difficult to make; you'd need something like the overhead wires for trolley buses. Switches will be a nightmare.
It would be an interesting exercise but I can't see it working reliably for displays and I can't see it being cost-effective.
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#8 Matt Dawson

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Posted 05 January 2010 - 12:04 PM

The main reason I suggested 9V equipment is that it's proven technology. It's 2010, a lot different from 1991 when 9V was introduced.

Besides, the obvious technological improvements make my system far better - constant supply of power (with battery if you wanted for backup/didn't want the 9V stuff) and it also means that the only thing that would run out is the controller (unless you used just the battery), due to it's reliance on batteries. The System would be very simple to implement, and would also mean that we could have PF accessories that were 'plug-n-play' as they wouldn't need a battery.

Edited by Matt Dawson, 05 January 2010 - 12:05 PM.

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#9 fred67

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Posted 17 March 2010 - 09:51 PM

What I would like to research is finding a way to pick up from the 9V metal rails (or the alternatives that are floating around) to power an RC or PF motor.

There was some discussion (maybe here... but I read a few things on bricklink) about using a dead 9V motor as a pick-up for the PF or RC motors.

Let's be clear on this...

A dead 9V motor with metal wheels (as long as it's not seized) connects to an RC motor (8886, the one that looks a lot like the 9V motor and is, itself, also 9V) or a PF motor.

The bonus is regulating the power and direction should have the same effect on each item; if you use a modified cable, you would also be able to control the train remotely (probably by keeping the power cranked up on the power pack) and inserting the IR receiver between the 9V motor and the other motor.

That's the theory, but I've yet to hear if someone accomplished this.  The method of modifying the cable was in a recent Brick Journal ***, which I'll dig up and peruse again to make sure I'm right.

My problem is that the method requires a dead 9V motor... or to sacrifice a good working one (NO FREAKING WAY).

I'm open to suggestions on an alternative method of picking up the voltage from the tracks.  Metal brushes maybe, but metal wheels from something would be ideal.

*** EDIT: Brick Journal Issue 7, Volume 2 - September/October last year.  The article is called "Make a 'Legacy' 9V to Power Functions Adapter," and involves using an 8886 Extension wire (the kind with both kinds of connectors - old and PF), and modifying it to power PF devices (the images show an IR receiver) using an old 9V battery pack... BUT HE ALSO SPECIFICALLY MENTIONS "it's use in places where mains power was more suitable (train speed regulator)."  Written by Rob Hendrix.

So the only question is how to pick up power from the rails?  Using this technique, you could indeed use an 8866 motor powered by rail BUT REMOTE CONTROLLED if you can pick up the current from the rails.  I wouldn't even do that... I don't need the conversion, I'd just go from rails to the 8866 motor and control the train speed/direction with the regulator; but the benefit of this method is, if you use the remote, the way to do it is to fully power the rails... which means if you have any lights or other electronics on the train, they are FULLY POWERED... no more lights whose intensity is proportional to speed... they'd be nice and bright the whole time, without running out of battery.

Edited by fred67, 18 March 2010 - 01:43 AM.




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