For My Next Trick.....

[AndyB]

A short video.

 

[Martin Wynne]

Thanks Andy.

I have now done this:

increased the size of embedded Youtube videos
switched off Youtube setting cookies on your system
switched off the annoying automatic jump to something else at the end

I can see it is going to take me a while to get everything here set up just right.

test:

cheers,

Martin.

 

[Rob Manchester]

Hi Andy,

Yes, stay alive caps are very handy, especially with sound fitted locos as they tend to go through an engine start-up sequence when power is lost even if the loco doesn't actually stall.

When you build a compensated chassis you can also have the loco ride over a matchstick placed on the track

Happy New Year to you. We are 9 hours(?) further into it......

Rob ( Manchester )

 

[AndyB]

Hi Rob,

Just eight hours. This bit of Idaho is on Pacific Time but the greater part of the state is on Mountain Time (7 hrs behind you).

The stay alive video might be bit different from what you are familiar with. It's not DCC and there is no decoder. Just smooth DC to the track and $7 worth of components on the loco.

And a Happy New Year to you and all Temploteers!

Andy

 

[AndyB]

A bit more action. This one might give a better sense of the inertia.

 

[Rob Manchester]

Hi Andy,
Thanks for the video. Good to see people that still like the older generation of RTR models - lots of people these days won't buy stuff unless it is in the latest box and has a DCC socket. Mind you some items in the current Bachmann range are still the same items as 40 years ago but in fancy boxes.

What is in the circuit for the stay alive/electronic flywheel. I assume you put a resistor and some diodes in there to limit the charge current for the caps ?

Rob ( 8 hours in front of you )

 

[AndyB]

Hi Rob,

It's very simple. Not even a diode and even the resistor might be overkill.

These caps are 8mm diameter by 12mm long and should fit in just about anything in OO. I plan to use them in a L&Y Pug.

Cheers,
Andy

 

[Rob Manchester]

Hi Andy,
1 Farrad caps ??? Surely not. Those are the ones the heavy metal guys use in their cars to stop the headlights dimming when the music is loud. Thanks for posting the circuit, but I am a little confused ( or thick ) about the way it would work in practice even though you show the loco running over the insulating material. What happens if you switch direction when the train is moving ?

The 'Pug' is a nice model. To make it even better this chassis kit is the thing to get : http://highlevelkits.co.uk/pugpage.html

Rob

 

[AndyB]

Hi Andy,
1 Farrad caps ??? Surely not. Those are the ones the heavy metal guys use in their cars to stop the headlights dimming when the music is loud. Thanks for posting the circuit, but I am a little confused ( or thick ) about the way it would work in practice even though you show the loco running over the insulating material. What happens if you switch direction when the train is moving ?

The 'Pug' is a nice model. To make it even better this chassis kit is the thing to get : http://highlevelkits.co.uk/pugpage.html

Rob

Hi Rob,

They are one Farad but caps in series works like resistors in parallel which makes the capacitance a "mere" quarter Farad. The caps are only spec'd to be good for 3 volts which is why there have to be at least four in series for a 12 volt supply. Two of them point in the opposite direction which makes the combination work like a non-polarized capacitor even though they are electrolytic.

If you switch direction while the train is moving the controller discharges the capacitors and recharges them with the opposite polarity. The loco just stops then reverses after a delay while the cap recharges. Obviously that's not exactly recommended operation but if the controller has proper overload protection nothing bad will happen. You can also reverse the controller polarity to act as an emergency brake although it might be better to connect a resistor across the track via a push-button switch to discharge the caps.

Cheers,
Andy

 

[Rob Manchester]

Thanks Andy, I am surprised that the caps are that small even with a 3 volt rating. There are lots of posts on RMweb etc asking how to make a stayalive for DC and none of them came up with an idea of how to do it whilst making it like yours so well done.
Rob

 

[AndyB]

Hi Rob,

AVR make a 1 Farad cap with an even smaller diameter body - 6.3 mm rather than 8 mm. It has a higher effective series resistance (ESR) and a lower peak current. It would probably work in a lot of situations too but I thought I better play it safe for this experiment.

Another option would be to just use two caps with a six volt motor. That might work well for small industrial shunting locos that are tight for space but it would require a controller adaptation. From what I have been able to determine so far the caps have pretty much the same effect as a large flywheel with the advantage that they take up a lot less room and they don't put a huge load on the motor while it's accelerating. You can also discharge them quickly without putting any strain on the motor.

I thought some of the reactions on RMweb were pretty funny although quite understandable. Nobody actually said they were going to write to their MP although I suspect some were seriously considering it

Cheers from a very wet Pacific Northwet. The recent snow is disappearing fast.
Andy

 

[Rob Manchester]

Hi Rob,

AVR make a 1 Farad cap with an even smaller diameter body - 6.3 mm rather than 8 mm. It has a higher effective series resistance (ESR) and a lower peak current. It would probably work in a lot of situations too but I thought I better play it safe for this experiment.

Another option would be to just use two caps with a six volt motor. That might work well for small industrial shunting locos that are tight for space but it would require a controller adaptation. From what I have been able to determine so far the caps have pretty much the same effect as a large flywheel with the advantage that they take up a lot less room and they don't put a huge load on the motor while it's accelerating. You can also discharge them quickly without putting any strain on the motor.

I thought some of the reactions on RMweb were pretty funny although quite understandable. Nobody actually said they were going to write to their MP although I suspect some were seriously considering it

Cheers from a very wet Pacific Northwet. The recent snow is disappearing fast.
Andy

Hi Andy,
I am normally hooked into the DCC + sound decoder route for locos but I do have some future plans for narrow gauge layout that have small locos that don't have enough space for decoder/speaker/caps so I was looking at runiing with DC on them and having a sort of surround system playing loco-type sounds to give some aural pleasure.

Shouldn't you be modelling Spokane Portland&Seattle or the Central Oregon&Pacific being as where you are now ? I have a lot of locos and rolling stock for US railroads and am trying to formulate some layout plans. Shame to say I don't have a 60x30' railway cellar with a house on top like many of the guys over there seem to have - I need to be looking at switching dioramas and shortline operations. The original blue box Athearn diesels of the 70's got me into US railroads but I never actually got to the layout stage back then - maybe this time ??

Thanks for your thoughts on the 'soft flywheel' - food for thought.

Rob
( wet and slushy in Manchester with more snow to come later this week - and going into another COVID lockdown tomorrow.)

 

[AndyB]

And here we go again

DCC is okydoky but it's also a wee bit spendy (to say the least).

Here's Andy's cheapo solution. Not that I'm saying you wasted your money. You won't get any cool sound effects with this.

Before:

After:

The difference is I connected the caps (those blue things) in the second video.

The caps cost less than $10. They add some "inertia" but, I think, more importantly they overcome the intrinsically intermittent electrical connection between the track and the motor.

 

[Rob Manchester]

Hi Andy,
Thanks for the videos. I had always thought the finger push was par for the course with standard DC ! The loco seems a good runner on the clean bits of track too.

Rob