Greg

I have learned over the years the internet communications has its limitations.  Generally if you cannot convey your  information in two email exchanges the chance of doing it further emails diminishes greatly.  If this topic is of real interest to you give me a call and I will put you in touch with Rutger, Bernd, Peter, Jurgen or one of the other manufactures of high end motor drive circuits who can go into the theory of this in whatever depth you desire.

If we were talking about brushless motors then indeed the flywheel mass would be way too small to serve a useful purpose.  Indeed a brushless moter is the gold standard. There are a lot of brushless motors in model railroad applications and they have a very big advantage of extremely smooth and uniform operation over the full 360 degrees of operation.  A brush motor is different.  The operation between poles is not uniform or smooth.  If you measure the stall current using the resistance test you will also generally find a difference in each pole.  When you rotate the motor you can feel the poles.  It all adds up.

Do the math.  When you have a PWM of 25-35KhZ even a 9 pole motor will have a very uneven operation when measured from the time one pole energizes the motor to the time the next pole energizes the motor.   When you pulse and measure the motor at 30khZ using a modern microprocessor, the time between poles from the perspective of the micro is a very long time, especially in slow speed operations.

A flywheel, even a very small one will tend to integrate these difference and present a more unified operation over the rotation of the motor.  From a simplistic standpoint it makes the brush motor appear more like the brushless one.

As you can see this topic has wondered far from the initial questions and is beginning to get into a depth not of real interest to most of the readers here.  Again if you have a real interest in this topic give me a call and we can work through it or get you in touch with the right people who can explain the theory better than I can.

Stan
www.tttrains.com/largescale

Quote from: BobHuddleston on November 10, 2008, 04:54:42 PM
Thanks for the answers.

I did check and make sure that all switches are on. I will check the counter weights later today. They were replaced when I purchased it.

I stopped in Caboose Hobbies this morning and they thought -- without seeing it -- that a gear might be stripped.

WIth power off, the engine rolls easily.

Bob

From your description it soulds like the locomotive and gears are working normally.

But their is a simple test to check everything out. 

Remove your QSI decoder and replace it with the dummy plug that came with your locomotive.

Now run the locomotive on normal DC.

If the locomotive runs fine you have isolated the problem to the decoder.  If the locmotive still does not work with the dummy board installed push the locomotive by hand on a non powered track with the dummy board installed and see if the headlights lights when the locomotive is being moved. Let us on the forum know the results of how the locomotive works with its dummy board installed and we can walk you through some simple repairs to get the locomotive working properly again.

Stan Ames
http://www.tttrains.com/largescale/

Quote from: Barry BBT on November 08, 2008, 04:15:32 PM
Mr. Ames,

I don't appreciate your condescending attitude.

You don't seem to understand either.

A slow moving flywheel will have little effect on anything, even with a mystery motor control unit.

Barry - BBT 

Barry

My humble apologies.  As one of your customers I have marveled at what you have been able to accomplish with improved mechanical designs.   I have great respect for your opinions in the areas you have expertise in and It was never my intent to be condescending nor do I believe it would be appropriate to do such a thing. 

The motor drive hardware and software now used by many of the top end model railroad electronics manufacturers is also a marvel.  When great electronics is combined with excellent mechanical designs the results are pronominal.

Normally the electronics are retrofitted into existing locomotive designs.  Several years back manufacturers begin to build locomotives the other way around by making specific mechanical improvements solely to improve the ability of the electronics to control the locomotive.  Locomotives designed this way are beginning to show up in a variety of scales.

So while it is indeed true that the K27 flywheel has little effect as a traditional flywheel, it does indeed provide a significant improvement when used with a hi frequency back emf motor drive circuit.  You do not need much mass to smooth out the motor back emf between high frequency pulses.  This concept is now being applied to locomotive designs in a variety of scales by a number of manufacturers.

As both electronics and locomotive design evolve I fully expect to see further improvements in the future.

Hope that helps.

Stan Ames
http://www.tttrains.com/largescale/

Quote from: Tony Walsham on November 08, 2008, 01:12:39 AM
Is that Plug'n'Play or Plug'n'Pray?   

Just a joke. 

Tony

Yes indeed product development cycles differ.

Quote from: Joe Satnik on November 08, 2008, 07:49:17 AM
Dear Stan,

You wrote:   "rectifier" and "AV"

Did you mean "bridge rectifier" and "AC"?

Why do you need the diode bridge?  Is there a DC fan to blow the smoke?

Sincerely,

Joe Satnik

Sorry yes "bridge rectifier" and "AC".  

The smoke generator has a voltager regulator and draws current. The desire is to not load the function wire with this current.  When the item in the socket brings the trigger line for the smoke unit to ground it is actually activating a transistor which conects the smoke unit to the locomotive DC.

The DC in the locomotive also activates the motor fan and the optos for the chuff.

Quote from: Tony Walsham on November 08, 2008, 08:21:49 AM
Joe, there is a fan in the K-27 boiler to blow smoke.
Only problem is it is mounted backwards and sucks the smoke down the chimney and blows it out under the boiler.
When the fan is reversed (a big job) it works specatularly well.

True indeed.  Apparently some K27s have the fan in backwards.  I have one that does not smoke well because of this and two that smoke exceptionally well.

Stan

To check out the smoke unit put in the dummy plug turn the motor off and place the locomotive on the track.  The smoke should work in the DC mode.

To get the smoke to work in DCC mode you need to have both a + and - voltage to the locomotive.

The Digitrax decoder has its - pin cut at the factory so you will have to add a small rectifier to make it function properly.  Any 1 amp or greater rectifier will work.

Connect the rectifiers AV input to the locomotives J1-1 and J1-12 connections and connect the + and - to the locomotives + to J1-6 and - pin to J1-7.

Hope that helps.

Stan

Quote from: Barry BBT on November 06, 2008, 02:39:06 AM
Just one observation, there is no need to lube the Pittman armature shaft.
It is a ball bearing motor with a thrust bearing between the "flywheel" and the motor housing.  The reason for the quotes is the uselessness of the flywheel, it has no effect on the performance of the motor, beside slower response.  The purpose of the flywheel is to provide an optical tape to be scanned for DCC.  I tested flywheels in the course of trying to solve a surging problem many years ago, larger flywheels than found on this loco and a smaller (8000 series) motor.

Not being able to actually lube the bearings in a Pittman is frustrating, but ineffective.

Barry - BBT 

Barry

You appear to be a little confused.  Let me try to clear up this confusion.

In the smaller scales the most common use of a flywheel is to is to act as an energy store to power the locomotive across small sections of dirty track.  To perform this function the mass of the flywheel must be sufficiently large to be able to store this energy.

In a locomotive with the mass that exists in the K27, to perform a similar function the mass of the flywheel would half to be quite large which is not practical.

So you are correct that if this is what you expect out of a flywheel then indeed such a small flywheel will have no measurable effect.

But that is not its purpose.

Nor is the purpose of the flywheel for an "optical tape to be scanned for DCC"

The purpose of the Flywheel in the K27 and other emerging Large Scale locomotives is to significantly improve the slow speed operation of the locomotive and in the case of the K27 this works exceptionally well.

To gain this benefit you will need to use a modern generation motor drive control circuit. 

Hope this helps

Stan Ames
http://www.tttrains.com/largescale/

If you hook up the battery to the P5 as detailed in the CVP instructions for AirWire installations and you use the inversion transistor for the P5 then the K27 internal optical sensors will work as expected.

Their is one sensor in each cylinder. You can select only one cylendar for a 2 triger chuff  or use both sensors for the more prototypical 4 cylinder chuff.

My k27s optical chuff produces a slightly out of time chuff which is protoitypical for an out of square locomotive.

When a locomotive first comes out of the shop the cylinders are in square and produce a chuff that is in time.  As the locomotive is used D valve adjustment will move slightly and become out of square.  When this happens the chuff becomes slightly out of time.   Because the Bachmann locomotive is one of the few that has chuff trigers in each cylinder it is one of the few in the market which can produce this realistic chuff.  By adjusting the triggers you can adjust the square of the locomotive as you desire.

Hope that helps

Stan Ames

Greg is correct, the second reference to 9 volts is a typo.  If you look at the photo at the bottom of the page you will see the standard Sierra Battery.

Stan

Quote
i was told that the sound in a three truck shay will work with just dc. will it work all funtions-bell- wistle etc.?

Perhaps I can provide a little more information to help you fill in the gaps.

The sound unit in the 3 truck Shay is an OEM version of the Soundtraxx Tsunami decoder that Bachmann uses in its HO, On30, and the Shay, the only difference being the amp rating (the Shay draws more current).

Various DCC sound decoders work differently in DC mode.   For example, QSI uses a polarity change to activate the various sounds, MRC uses a radio transmitter, LGB and Phoenix use auxiliary contacts.  The Soundtraxx OEM sound decoder that Bachmann uses only supports an auto mode in DC operation.  This means the chuff is active and you can configure the whistle and bell to come on at start up.  You or your dealer can configure this auto mode by setting the values of various parameters in the decoder.  This configuration requires a DCC programmer.

Another product in the market is the Black Box from MRC.  This allows a DC user to control any of the sounds in any DCC decoder while using DC.  I do not believe that a hi amp version for Large Scale has been released yet but I may be mistaken.

Quote
what do i need? i use a bridgewerks td-25. will the bachmann dcc system work with this or is there something elce i should use?

Bachmann makes 2 DCC systems.  With either you can fully control the sounds in the 3 truck Shay.  Neither system provides enough current for Large Scale use.  For Large Scale you will need to augment your Bachmann system with a power station (booster).  Bachmann makes a 5 amp one that comes with its own power supply.  Other DCC manufacturers make 10 amp versions and they also work with the Bachmann systems or other DCC systems in the market.

Hope that helps.

Stan Ames
http://www.tttrains.com/largescale/stan.htm

It is often very hard to identify a problem from internet posts.  I have several 2 truck shays and they run smoothly.

Quote
this shay is also stalling at points at slow speeds.

This is a hint which may explain your poor performance.

From your posting it sounds like a shay with very dirty wheels that is getting intermitmtnt pickup.  Since it is a new shay I doubt the wheels are dirty but perhaps the pickup is not cunducting properly.

With an ohm meter checkthat all wheels per side are connected together.  My bet is that you will find onw or two truck sides that are not picking up power.

Just a guess

Stan Ames

Greg is correct.  I normally use the P5 and forgot that the 2K2 was also DCC capable.

See page 19 of your Airwire manual.   Make sure the battery connection is made between the Airwire and the 2K2 as per the AirWire manual.


Sorry for the confusion.

Stan

The installation instructions are correct and have had multiple installations.  Each installation was approved by the respective manufacturer prior to its being posted. They can also mix and match the installation approaches as they are rather generic.  I have a P5 in my K and it works great.

The reason your installer recommended a P5 over a 2K2 is because your AirWire receiver is designed to control a sound board that has a DCC input.  The P5 has such an input.

Another alternative would be to use the QSI sound decoder together with the GWire receiver as this combination will also work with your AirWire system.

If you use the optical chuffs for sound you may notice that the chuffs are slightly out if time which is exactely as most K27s actually sound.

Hope this helps.

Stan Ames
http://www.tttrains.com/largescale/stan.htm

Quote
We've been waiting since December for the install review/how-to...here they are... and RCS is still the only provider of a "True" Plug and Play device to operate the Bachmann K...

Cale

RCS does indeed have an excellent PNP product for the socket in the K27 for its RC/battery users.

There are two others currently in the market and a few others expected.

For DCC/Sound users the ESU board is a true plug and play board, that has full access to all the K27 sound and lighting functions.

For DC, DCC, and RC users the QSI board is also a plug and play board but at the present time is only designed for the lights, motor control and sound.  The other lighting functions are accessed through the switches behind the smokebox door.

The QSI board is currently the only board designed for all three communities.

Most QSI users use the calibrated automatic chuff.  This is one of the best auto chuffs in the market and was designed this way because most Aristo-Craft locomotives do not have a sound cam.  Myself I prefer the optical triggered chuff.  A simple inversion transistor is currently required for the QSI PNP board for those users that want to use the optical chuff.

Hope that helps.

Stan

Back in December Bachmann asked if I could assist with some installation documents for various 3rd party control and sound systems.  The first drafts were completed in early January.  The time since was spent in coordinating the installation write-ups with the various manufacturers and waiting for the Bachmann WWW site to stabilize to a point where the WWW master could load them.

To access the K27 installation documents please click on the “Product Reference” tab at the top of the page.

Then from the Product Reference page go to the Manuals tab, K27 manuals, Sound and control Products.  This will bring up the page for the electronic installations.

Scroll down to the type of install you desire and click on the hyperlink for the product information you want.

The responsibility for ensuring the installation document is correct rests with the manufacturer of the 3rd party equipment, so for any questions you need to check with them.  I have personally done the installs listed to check them out.

There have been a lot of changes since these pages were first written.

ESU â€" Their adaptor board was shown in Nuremburg and has since been plugged into a K27.  I have not yet touched the actual board (will next week), but ESU reports that the board can control all functions and the integrated sound system works without the need for any additional modifications.

RCS â€" RCS has shown their new plug-in board at the ECLSTS.  It also allows the ability for a direct plug in Phoenix P5.  This installation has been published several times on the board.  At last check Philadelphia was waiting for a PDF version to update the older one now on the site.

AirWire900 â€" This was one of the first installations that Roger completed back in December.  The installation document was sent to CVP for review.  They indicated that they desired Bachmann to send them a locomotive so they could check out the install.  Not sure what the status of the review is.  The installation is rather straightforward.  The key element is to follow the CVP recommendations for a normal install by hooking the battery directly to the P5.

Aristo-Craft â€" Aristo-Craft has a plug and play board but no longer has this board in the market, so an installation document was not completed.  Aristo-Craft has announced a new RC plug-in product, but the date for release or characteristics are unknown.

Digitrax â€" Digitrax has discontinued their plug and play product. A replacement has as of this writing not been announced.


I am sorry but I will be off-line for a few weeks so I will not be able to answer questions till I return

Stan Ames
www.tttrains.com/largescale

Nick

You have an older version of QSI software. From experience I am very confident that the version you have will not work properly.  At a minimum you will need to upload to the latest version of K27 sofware that is on the QSI solutions WWW site.

Since the lights work in DC more the K27 is fine. Once you upload the software to the current version, you will be able to determine if you have a hardware problem in your QSI product. One can not tell until you have the current software.

Stan