# Shout-out to Airwire G2 Motor Bump Value



## East Broad Top (Dec 29, 2007)

Tuscarora Railroad #2 is built on a Bachmann 2-6-0 chassis, but despite my best efforts, I always found this particular loco's performance underwhelming. It was lethargic at best, and slow-speed control was seriously lacking. The motor just didn't have the oomph to get things going smoothly until a certain voltage, at which point it would take off at nearly a scale 10 miles an hour--about 2/3 "maximum speed" on my railroad. Performance would degrade with time as the motor got warm. (This seems to have been unique to this loco, as another 2-6-0 I had ran a good deal better than this one.) Well, I had occasion to jockey some electronics around in some of my locos, after my dad blew out a Sierra sound system and I offered one of mine as a replacement. Through this, I installed a Phoenix P8 sound system in this loco with the "Dockside" sound set. I had put this same sound set in one of my dad's locos and fell in love with the whistle. Alas, when I went to control the P8 with the original control system, I couldn't trigger the short "toots" on the sound board that I found particularly appealing. So I removed that control and replaced it with an Airwire G2 board since I knew that would allow me better control of the whistle. (Yeah, I'm weird. Sound performance trumps locomotive performance for me.) In reading through the instructions on the G2, I read about the "motor bump value" control the board offers. This is a quick pulse of voltage designed to give the motor just a little extra "kick" at slow speeds to get the motor turning, but keep speeds very slow. I figured it couldn't hurt to try it to see if I could get better slow-speed performance out of this loco. 

In the immortal words of auctioneers everywhere, "Sold!" 

Turning that feature on, thus giving the locomotive just a little bit of kick made a world of difference in how this loco performs. It just c-r-a-w-l-s along now. Even after running for two hours straight, I can switch cars in and out very slowly and smoothly; something that was essentially impossible prior. If I had to grade its performance, it went from a C- to an A. I'd love to see the output on a scope to see what's really happening with the pulses, but certainly the results speak for themselves. It's finally the locomotive I was hoping it would be when I first started building it.

This feature is only available on the G2 and Drop-In Airwire boards. The original Airwire board does not have this feature. So if you've got a particularly lethargic loco, this may be just what the doctor ordered in terms of a cure. I will say that the original control system has proven itself worthy in all of my other locos; it's just that this one is particularly temperamental and definitely benefitted from the extra TLC. So if you've got a loco that you don't run as often as you'd like for lack of slow-speed performance, this might be a solution to your problems. I wasn't expecting it--I just wanted something to let me blow the whistle quickly--but I'll definitely take it.

Later,

K


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## TonyWalsham (Jan 2, 2008)

Kevin, 
Was the donor chassis one of the Spectrum 2-6-0's? 
If so did you remove the motor suppression pcb from the end of the motor? Some of them had one (or both) of the caps in the wrong way around.


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## East Broad Top (Dec 29, 2007)

Yes, and the PC boards were removed. Since I have scrapped the first 2-6-0 (the one that ran okay) to use some of the parts for my EBT #7 project, I was getting ready to swap the motor/gearbox and the wheels to see if that made any difference (but looking forward to that level of surgery like a root canal). I think it's just one of those quirky things with this particular motor. But since it seems to be resolved without needing to replace the running gear, I'll just smile and wave as it rolls by. 

Later, 

K


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## Greg Elmassian (Jan 3, 2008)

That's good to know the CVP finally added this feature. It's common in DCC decoders. Even the old original NCE D408 has it. I think they call it "torque compensation kick", CV's 116 & 117. If you ever get a wild hair you should try a decoder with BEMF motor control, it will blow your mind another "level". 

Glad you found a way to easily improve the running qualities of your loco. 

Greg


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## K27_463 (Jan 2, 2008)

Airwire did not "finally add this feature" The g2 has been sold for about 4 years and has had this capability all that time.


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## Paul Burch (Jan 2, 2008)

Isn't the cruise control in the G2 a form of bemf?


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## East Broad Top (Dec 29, 2007)

Isn't the cruise control in the G2 a form of bemf? 
Yes it is, and it works well to hold trains to a constant speed regardless of grade--quite a nice feature on my dad's railroad with its 4% grades. 

I didn't mean to imply this was "new" technology by any means--this was merely the first time I've had a locomotive whose slow speed performance was such that it needed a helping hand; a hitch in its giddy-up that just needs to be powered through on occasion. I figured there may be others who hadn't thought to try that feature, or might have a mix of original and G2 boards they might consider swapping around to help particularly lethargic locos. Since our choice of DCC boards capable of running in a battery R/C environment is quite limited, we must avail ourselves of whatever technology is around for our use. When Airwire finally gets around to introducing a higher-amperage version of their recently-announced "Converter" generic wireless receiver, I'll readily jump in and play with some of the other DCC decoders on the market. (I have no idea whether Airwire plans to do so, mind you. Zimo--or someone--announced a similar receiver a while back, but I've not seen it yet on the market.) 

Greg, on the QSI, I know the PID settings are there for enhanced slow speed operation, but to my understanding, that only works in Regulated Throttle Control. CVs 116 and 117 in the QSI manual are sound control CVs, so if there's a "torque compensation kick" CV with the QSI that's unrelated to the PIDs, that'd be great to know. PIDs are black magic, so a simple way to similarly enhance performance--especially in Standard Throttle Control--would be great. A search for "torque" in the QSI DCC guide came up empty. 

Later, 

K


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## Greg Elmassian (Jan 3, 2008)

I did not mean to derail the thread, nor bring up QSI, sorry. 

There's news about RTC and QSI I will reserve for another thread, so I won't go into detail answering that question. 

PID's are used by EVERY system that uses BEMF, just not all decoders are adjustable. They are definitely not black magic, but you need to understand them a little to tweak them. They are actually the initials of the 3 parameters in the equation to calculate the BEMF "response". 

In my response, was just saying that the "kick" or "bump" feature has been in many DCC decoders a long time, and the example I gave was a NCE D408, with it's CV's. 

Yes, the "cruise control" is definitely using BEMF, and I forgot that feature, sorry. It's BEMF "tuned" to one "extreme" , a pretty cool feature.

Greg


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## East Broad Top (Dec 29, 2007)

Thanks. Didn't know if the CVs you gave were NMRA standard CVs or decoder specific. (And I don't mind a little excursion within threads if it answers questions I have.  ) 

Later, 

K


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## Paul Burch (Jan 2, 2008)

Kevin,
Your comments on the motor bump feature got me curious. I have never played with it. So I put my two Aristo 2-8-0's on parallel indoor tracks sitting side by side. Without changing the settings and the speed steps at 28 they both start moving at speed step 3. Very smooth as far as I was concerned. I then set cv56 to 25 and cv57 to 3 on one of the locos. The loco I changed now starts moving on speed step 1 at such a low speed that you hardly notice it is moving. 12 seconds from the leading edge of one tie to the next or in my case 3/4". So thank you for posting. I don't know why I hadn't played with it before. I will be taking these locos to Marty's.


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## East Broad Top (Dec 29, 2007)

I just re-programmed the G2 that's in my Bachmann outside frame 2-8-0 ("Connie") with a Barry's Big Trains replacement gearbox. In all honesty, there was nothing about the performance of this loco that I found lacking with just the straight throttle. Start-ups and stops were very smooth (as we'd expect from Barry's drives.) I tried this just on a whim--to see what difference it made. I was tweaking the sounds anyway, so why not? 

Yeah... 

If you've got a G2 (or now G3)-equipped board, you owe it to yourself to turn this function on. 

Later, 

K


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## Gary Armitstead (Jan 2, 2008)

I have to agree Kevin! If you have a G2 board, these "bump" CV's make a world of difference in performance.


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## Bill Swindell (Jan 2, 2008)

I am woiking on a Connie right now with a G-3. Do you have any suggestions at to whatr values you ended up using for CV56 & CV57?


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## East Broad Top (Dec 29, 2007)

Sorry, Bill, I didn't see this until just now. I forget what the values I used were. I usually set the frequency fairly high, and then play with the amount, alternating low/high values until I end up with something in the middle that is fairly smooth.

Later,

K


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## Gary Armitstead (Jan 2, 2008)

Bill Swindell said:


> I am woiking on a Connie right now with a G-3. Do you have any suggestions at to whatr values you ended up using for CV56 & CV57?


Bill,

I just saw this post. Hope I can help. I have a Connie with Barry's drive and a G2. My settings are as follows: CV5=0, CV6=50, CV56=40 and CV57=1

I made these settings on November 30, 2012 and are still working great with Barry's drive.


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