Intermountain Cab Forwards

[SirTainly]

Cool, thanks guys. Bit to big to usefully fit in my case, need to get some running in before the toys go into storage.

[dclyde]

Well, I picked up an AC-12 from MBK a few days ago.  I installed a TCS X decoder I had laying around and programmed it.  It ran slowly at first but improved dramatically once it was broken in.

Our layout is Atlas Flextrak on foamular.  As such, I can't say that any part of our layout is perfectly flat.  I noticed some rubbing on the cow catcher in a couple spots on our layout.  A small amount of filing of the cow catcher took care of that.

So far, so good.  It runs like a champ.

Dave

[sizemore]

I finished tweaking the decoder settings in mine over the weekend. In order to get some decent slow speed control I set the "pulse" (CV-65) to 10 or so, and the "strength" (CV-66) to 55. I kinda think the motor is anemic, or there is a lot of friction in the system due to Amp draw, throttle response and watching the slow speed operation.

The S.

[victor miranda]

the motor in the loco is different from most n-scale motors.
it has about twice the resistance as other motor
A Kato motor at 18 ohms and the Intermountain at 35.

the voltage ends up at about twice the usual number

With the gear ratio at 40:1 an anemic motor is not a worry.

victor


 

[sizemore]

the motor in the loco is different from most n-scale motors.
it has about twice the resistance as other motor
A Kato motor at 18 ohms and the Intermountain at 35.

the voltage ends up at about twice the usual number

With the gear ratio at 40:1 an anemic motor is not a worry.

victor

Could you elaborate more on how the motor is different? I understand ohm resistance but what is causing it?

The S.

[up1950s]

Ok I checked the traction tires for slippage and all 4 were ok . I cleaned all drivers and test track with alcohol . I retested the tractive and now I get 22 grams , better , but not so hot either . I also noticed that while cleaning the drivers upside down that the drivers would jam to a stop at times , and reverse was needed to unjam it .  Here is where it sits on my tractive list .

[GaryHinshaw]

Whoa, the Athearn Big Boy really hauls a$$, eh?  You gotta love the Walthers 0-8-0.   

[victor miranda]

the motor in the loco is different from most n-scale motors.
it has about twice the resistance as other motor
A Kato motor at 18 ohms and the Intermountain at 35.

the voltage ends up at about twice the usual number

With the gear ratio at 40:1 an anemic motor is not a worry.

victor

Could you elaborate more on how the motor is different? I understand ohm resistance but what is causing it?

The S.

I measured to two motors for resistance.
I was trying to determine If I had a bad pole.
the IM motor seems fine.

I do not know this for certain as I have not made these measurements
the usual way to raise the resistance in a motor is to use
finer wire or more wire.   most times one does both.

If I understand motor construction correctly...
the increase in resistence allows the motor to run at higher voltages.
I am not sure what the other reasons might be for that difference in resistance.

victor

[SkipGear]

More wire mass on the armature results in more torque. Finer wire reduces the air gaps between each turn of the motor meaning you can put more on in both turns and mass. A higher turn motor will make more torque, a lower turn motor makes more RPM.

Turn - each wrap of wire around a segment of the armature.

This all comes from RC racing. A typical RC rock crawler motor is around 55 turns of very fine wire so that you good low speed torque to climb. The off road race motors are around 10-12 turns and onroad was down around the 8-9 turn range, for those that still use brushed motors. RC is just about completely switched over to brushless now. I bet we will eventually start seeing brushless in model railroad, first probably O or HO, something that can use the torque that can be generated. It would amost have to be DCC though because you need a motor controler to drive the motor.

[victor miranda]

ok they are clearly after more torque
I think that is good...
the motor uses more power than I am used to seeing
so extra torque may be a good explaination.

geared at 40 to 1 and an extra torque motor
that seems not to get to warm....

I expect the motor can handle the load of hauling cars...

victor

[SkipGear]

Right now, the only thing wrong with the AC-12 in my opinion is that we still don't have ours at the shop. The distributors most recent date is that they are shipping tomorrow (Friday).

IM really should have held them all at the warehouse until testing was done. They are fortunate that the units for the most parts are getting good reviews. With this release strategy, it they were dogs, you would see a lot of unhappy customers and shop owners stuck with stock. Already we have lost a couple sales to the mail order shops that were able to get theirs before us. Fortunately, I am not worried about those loco's getting sold as it looks like this one is a winner.

[sizemore]

Ok I checked the traction tires for slippage and all 4 were ok . I cleaned all drivers and test track with alcohol . I retested the tractive and now I get 22 grams , better , but not so hot either . I also noticed that while cleaning the drivers upside down that the drivers would jam to a stop at times , and reverse was needed to unjam it .  Here is where it sits on my tractive list .

Rich,
When it hangs up, stop it immediately and you may note that the driver's side-rod pin closest to the steam chest is hanging on the crosshead OR crosshead guide due to some lateral play in the drivers. You may also find that the eccentric arm for the eccentric rod is not properly offset from the wheel center.

The S.

[up1950s]

I did stop it , this ONLY happened when it was upside down and some cleaning pressure was applied to a single tread , and as such canting the driver set to one side of the loco . So until it happens to a right side up , and on the rails hands off situation I will just dismiss it as excessive manipulation by me , though worth the mention as general knowledge for others when they clean their drivers .