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Post by dave on Oct 4, 2015 21:59:43 GMT -5
Good evening,
Today, I test ran 3 Z-scale locos that I purchased over the last couple of months. First is an AZL GP7; next is a MTL GP35 and finally, a MTL SD40-2. I am using 3 sections of Rokuhan straight track a Z-Track Snail 9V controller. The controller is about 4 years old but I put a new battery in it today.
All of the locos ran very slowly (I am used to N-scale). Even at full throttle, they seemed very slow to me. The AZL was the fastest with the GP35 second and the SD40-2 the slowest.
My question is whether these locos would run any faster using a Rokuhan controller; I just feel they are too slow using the Snail controller and question whether they would even be able to climb a small grade with any cars attached.
Any input from your experience and recommendations would be appreciated. Thanks for your help.
Dave
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Post by domi on Oct 5, 2015 3:35:54 GMT -5
Indeed are they able to climb grades with trains behind or aren't they?
Myself I run a mix of AZL and MTL locos. All of these are within a range between really slow and "mid pacer" (I've no experience with N scale but when reading reports about average N scale motive power in MR I'm dazed to see most N scale locos running at 120 scale mph under max voltage...). I run my trains with a Passmann snail speed controller.
And although they are slow, all of them pull like mules.... As I'm working on a current railroad that depicts mountain railroading and planning a future railroad that will be a derelict shortline, I don't care about speed.
So about your problem I'm wondering: what are your grades? How many locos are you running simulataneously?
In my opinion, that could be a lack of amps. Maybe the battery powered controller, even giving 9 volts if in the beginning, is a little bit low on amperage for your needs?
Dom
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Post by Rob Albritton on Oct 5, 2015 7:05:37 GMT -5
Good evening, Today, I test ran 3 Z-scale locos that I purchased over the last couple of months. First is an AZL GP7; next is a MTL GP35 and finally, a MTL SD40-2. I am using 3 sections of Rokuhan straight track a Z-Track Snail 9V controller. The controller is about 4 years old but I put a new battery in it today. All of the locos ran very slowly (I am used to N-scale). Even at full throttle, they seemed very slow to me. The AZL was the fastest with the GP35 second and the SD40-2 the slowest. My question is whether these locos would run any faster using a Rokuhan controller; I just feel they are too slow using the Snail controller and question whether they would even be able to climb a small grade with any cars attached. Any input from your experience and recommendations would be appreciated. Thanks for your help. Dave Hi Dave, Good question. Our AZL GP7 is rated to make full speed at 12 volts (just like N scale) You were using a 9 volt power pack. So yes, a Rokuhan 12 volt power pack will make them run faster. And they will climb a bit better too. Best, -Rob(A) AZL |
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Post by Hans Riddervold (AZL) on Oct 5, 2015 10:22:22 GMT -5
Hi Dave,
Which AZL GP7 do you have? If it is a UP, PRR, C&O or Nickel Plate, the motor is a 8V 8mm Faulhaber. All other AZL GP7s and GP9s have the 12V 7.5mm motor.
Sincerely, Hans
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Post by boxcarwilly on Oct 5, 2015 11:25:28 GMT -5
Hi Dave:
I have had the same problems with my AZL engines as you do and yes, like you I like to run a lash up of mixed AZL/MTL engines. I find that most of my MTL engines will run faster than my AZL's at the same throttle setting on my pack. I presented this problem to AZL several months ago and was told by Hans and Rob that no two AZL engines will run exactly the same because of minute differences caused by the manufacturing process. I have never found this answer to be satisfactory, but have accepted it and proceeded accordingly. If you put a MTL GP35 on your track and run it at say 50 scale mph, it's a safe bet that your AZL GP 38 will not run at the same speed regardless of where you set your throttle. It's an unfortunate fact. To be fair, no 2 MTL Geeps will run at the exact same speed either so, the problem is consistent across the board.
What I have had to do, is put all my engines of one type, ie: MTL GP9's, 35's, SD 40's on the track, give them the juice and observe which ones are faster then others, then number them accordingly. I have done the same for my AZL GP 38's SD 70's and 75's. That way, I know which ones I can put together to pull my trains at as close to a realistic scale speed as possible.
I too have a layout based solely on the Rockies and during my many experimentations I have found that I can only pull so many cars with so many locos up my 2% grade. For example, I am currently running a hopper train of 20 cars pulled with 2 AZL SD 75's and one MTL SD 40. The grade is extended over 16 ft. At a scale speed of 50kph, this train barely makes it up the entire length of the grade before reaching a level track. It slows right down to a crawl because of the weight behind the locos. Not a big deal, however, what I've experienced is weak couplers. I start with a specific number of engines, then add 5 cars at a time and do one complete revolution of my layout. I continue to do this until I get to the point where cars pull apart on the upgrade. That tells me how many of that weight of car I can pull with that number of engines. MTL and AZL couplers are inherently too weak to pull long trains. I have tried making up trains with heavy cars up front and lighter cars behind, but on the up grade, anything over 20 cars, just will not hold together. I would have thought that putting the lightest cars at the end would reduce drag, but it doesn't. It matters little how many engines you put at the head, it's the couplers that for me at least, are the problem. That's my biggest disappointment in Z scale. I never had this problem with HO or N. On my layout, running 50 car grain trains from the prairies to the coast through the Rockies is a dream that won't ever come true. The same with tankers, containers, and mixed freight. The couplers just can't handle it. So unless someone somewhere comes up with stronger couplers that can do the job and yet remain as realistic as possible, then I have to restrict my trains to 20 cars or less. I suppose, in the grand scheme of things, a 20 car container train is realistic enough to the average person, when running on my layout through the Rockies. But to those of us who try to model actual prototypical rail lines, it's jut not realistic enough. I share your pain.
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Post by dave on Oct 5, 2015 13:08:19 GMT -5
Hans, it is a CB&Q GP7.
Also, will it hurt Micro-Trains locos to use the 12V Rokuhan controller?
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Post by domi on Oct 5, 2015 15:52:04 GMT -5
Speaking of Geeps, one of my GP38 has a little jerky motion, with a rythmic speed change. Looks like there would be a hard spot on one of its gearings. I ran the locomotive 30 minutes each way to break it in, but the problem remains.
What do you guys recommand to solve this?
Dom
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Post by zscalehobo on Oct 5, 2015 16:01:52 GMT -5
Speaking of Geeps, one of my GP38 has a little jerky motion, with a rythmic speed change. Looks like there would be a hard spot on one of its gearings. I ran the locomotive 30 minutes each way to break it in, but the problem remains. What do you guys recommand to solve this? Dom Your first communication should be with your authorized AZL dealer who sold you the item. If that doesn't help, then you contact AZL here: azlforum.com/thread/387/azl-customer-support |
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Post by domi on Oct 5, 2015 17:40:21 GMT -5
I don't even remember who was the seller! And as it's one of my undecs, I've no way to recognize which comes from where... But anyway, I'll directly try with AZL if needed.  Dom |
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Post by dave on Oct 5, 2015 19:16:36 GMT -5
Rob,
I was just looking at the Rokuhan controllers and they say that the maximum output is 10V at 800mA. The AC adapter has an output of 12V and if you use the 8 AA batteries, that is also 12V. With the 10V max output, will it really make a difference vs. the 9V snail controller? Thanks again for your help.
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Post by markm on Oct 7, 2015 14:39:27 GMT -5
Dave,
The difference between the Rokuhan and Snail isn't so much the voltage as the manner in which the power is supplied. The Rokuhan uses a more sophisticated scheme than the Snail and in theory ought to provide a bit better pull.
Mark
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Post by Rob Albritton on Oct 7, 2015 16:21:49 GMT -5
Rob, I was just looking at the Rokuhan controllers and they say that the maximum output is 10V at 800mA. The AC adapter has an output of 12V and if you use the 8 AA batteries, that is also 12V. With the 10V max output, will it really make a difference vs. the 9V snail controller? Thanks again for your help. Lots of technical things going on here: 1) input voltage 2) output voltage no load 3) output voltage under load 4) Rectifying AC to DC 5) pulse power (frequency, cut off, etc) 6) motor efficiency at various voltages (it is not linear) 7) static motor load due to design 8) static motor load due to environment (dirt, hair in gears) 9) manufacturing tolerances of the motors 10) manufacturing tolerances of the locomotive drive train My point is that LOTS of things go into how fast a locomotive runs. Unfortunately, the smaller the scale, the greater the influence of any one factor. When Marklin released Z scale in 1972 their solution was to basically put a slot car on rails. Trains rand at warp speed, but had very little low end control. Time has passed and more and more people want their trains to run at more prototypical speeds, which in Z scale may look a little slow to the untrained eye. But to answer your question directly, I measure max 10.5vdc of my rokuhan controller at the rails. I also use a Kato N scale power pack with my newer AZL locos with no problem. Kato used 15vac input and about 12vdc to the rails. I suspect your snail controler is actually providing about 8.5vdc. Start voltage is usualy somewhere between 2.0 and 2.5vdc, and I find that our motors tend to max out their power curve at about 10.5vdc. So that puts the useful range of power at about an 8 volt spread (10.5-2.5=8) with the snail your getting about 6 volts of that spread, or about 75% of max speed. So yes, I suspect a rokuhan or other controller will probably give you a nice speed bump. I can't swear to it due to all the variables listed above, but its's a little like chicken soup: it can't hurt. Good luck! -Rob(A) AZL |
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Post by dave on Oct 7, 2015 21:54:06 GMT -5
Rob,
Thanks for your help. I have several of the Kato powerpacks and I will give one a try. I will report back with the results. Thanks again.
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Post by dave on Oct 10, 2015 17:02:49 GMT -5
Good afternoon,
I got the Kato power pack out and did some testing. At full throttle on Rokuhan track, it was 13.6 volts. I scaled back the throttle to 11.8 volts and made a mark on the throttle. I then tested the GP35; obviously, it run much faster at 11.8 volts and it seemed to run OK. I then tried the MTL SD40-2 and it was about the same result. Finally, the AZL GP7; it ran very nice; smoother than either MTL. I was happy with speed increase but I think the happy medium is about 9.8V to 10.8V. I am going to make some sort of small stop I can glue to the Kato power pack so I don't exceed that voltage by accident. Thanks to everyone for your help.
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Post by dave on May 4, 2016 6:53:48 GMT -5
I wanted to revive this thread to ask about another controller. On my layout, I would like to panel mount a small controller and am looking at the the Medvend AN-C-1 controller. Has anyone used it and if so, results and comments would be great. If you have used it, what power supply are you using? I will be using MTL, AZL and Marklin DC locos. Thanks for the help.
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