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Let's Talk...INERTIA???
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 Posted: Tue Mar 22nd, 2016 05:06 pm
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Bob D
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I'm O-scale, but I figure this would apply to all scales.

I know there's adjustments for the Deltang Rx65x (RCS of Australia ALPHA3v2) concerning Inertia, but I guess I'm really not sure how inertia works.

From the v611 features/instructions, inertia/soft start/momentum are the same thing?

Is there also an adjustment in the transmitters (I use the RCS Tx3 and Tx7k)?  I don;t think so but thought I'd ask.

What can I expect to see when the engine/train starts to move or starts to stop if inertia is changed?

What about inertia in a 0-6-0 switcher that doesn't get over a certain speed most of the time anyway?

Most, if not all, of my engines (steam and diesel) have flywheels on them also, so what effect would the flywheel AND inertia have together?

Would inertia help an engine that has poor-fair-good-excellent gearing?

Would inertia help a larger engine more than a smaller engine?

The v611 instructions indicate there's "immediate" to "8 seconds", is that a delay time or is the speed gradually ramped up during that 8 seconds?

I suppose the best way is to try it and see, but I thought I'd drink from this vast well of knowledge first :thumb:

BobD.



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BobD
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 Posted: Tue Mar 22nd, 2016 08:13 pm
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Rod Hutchinson
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I have a deltang TX22 throttle. The inertia is controlled from that. You may use it or not use as you wish.

Inertia slows the start and end of the loco speed cycle.

My locos are geared locos so I don't use inertia at all.



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 Posted: Tue Mar 22nd, 2016 10:46 pm
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davecttr
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I believe the Rx 'on chip' inertia ramps between 0 and 8 seconds but have only used the default so far. The inertia knob on my Tx-22's are actually timed throttle increases which do not change the 'on chip' inertia. There could be some interesting combinations there!



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 Posted: Wed Mar 23rd, 2016 01:11 am
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NevadaBlue
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I use inertia on my Air Porter loco and it makes movement much more realistic I think. Instead of the motor just stopping when you turn down the throttle, there is a 'soft stop' if you will. I like it.
I need to experiment more with all the settings on the transmitter.



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 Posted: Wed Mar 23rd, 2016 08:42 am
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DavidT
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Bob, I expect models to have a much higher power to weight ratio than full size trains so can benefit from some electronic aids...

1. The Inertia setting in the Rx does what I expect a flywheel to do which is to dampen speed changes in a short timescale. If you have both then both are having an effect.

2. The Inertia control on the Tx simulates train 'mass' which slows down speed changes over a larger timescale (up to 1 minute with center off motor control). The instructions for your product will tell you if you have this control.

3. BEMF reduces the need for operator skill/finess to control stiction and wheelslip. My Rx do not have BEMF but do have a minimum start power setting which perhaps falls into this category.
Regards, David.

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 Posted: Wed Mar 23rd, 2016 10:53 am
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Bob D
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Thanks guys :2t:

So changing the Inertia setting causes the speed to ramp up/down in a 0 to 8 second time frame.

The MIN voltage (Start Power) setting can be set so there's 0 to MAX volts on the motor as soon as it is turned on.

The reason I'm asking is I have 1 or 2 engines where I have to turn the throttle knob almost 40 degrees to get the engine to move, and at that point it suddenly starts moving, quicker than I would like. My other engines (different brand than the 2 in question) start to move at around 20 degrees of turn of the knob.

It may be due to some binding (in which case changing settings probably won't help) and I'll take a look into that. It could also be the gear ratio, my engines with higher ratios (like my Williams brass 4-8-4, 43:1) start off smoothly with a very small turn of the knob.

I may want to change the MIN start voltage first, then play with the Inertia setting.

The 2 engines in question have their engines mounted at an angle with the engine mount screwed to the chassis. The screws may be too tight and causing binding between the gear/worm on the motor shaft and the gearbox. I may loosen them up a bit first and see what happens.

BobD.



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 Posted: Wed Mar 23rd, 2016 04:24 pm
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NevadaBlue
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I have found that different motors have a lot different starting characteristics. My Air Porter starts so beautifully, I can make it start so slow you have to set stakes to see it going. My Little Mine loco has a different type of motor, one of the old HO locomotive motors. It doesn't like to get going slowly. I'll have to look into the settings on the Rx for it I guess.



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 Posted: Thu Mar 31st, 2016 01:52 am
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Bernd
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I've been experimenting with a mechanical momentum system using an Eddy Current drive.

http://kingstonemodelworks.com/ECDtb.html

Bernd



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 Posted: Thu Mar 31st, 2016 11:22 pm
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Bob D
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Bernd, I saw where you had mentioned this before, interesting!

It got me looking at my old magazines and found this Fluid Drive clutch in the August 1951 Model Railroader:


I guess as long as it doesn't leak we'd be OK, but it could mess up all the fancy electronics we now put in our engines.

BobD.

Bob--Sorry, but I had to remove the Model Railroader article. Kalmbach is very nasty about their copyrights

Herb



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 Posted: Fri Apr 1st, 2016 01:56 am
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Budd
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Bernd wrote:
I've been experimenting with a mechanical momentum system using an Eddy Current drive.

http://kingstonemodelworks.com/ECDtb.html

Bernd


Who is Eddy Current and what scale does he model in?

???

Wayne from Oz.



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Modelling the 3'6" gauge railways of South Australia of course.
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