From nw-modeling-list at nwhs.org Mon Jun 8 12:46:16 2009 From: nw-modeling-list at nwhs.org (NW Modeling List) Date: Mon, 8 Jun 2009 12:46:16 -0400 Subject: P2K GP30 speed? In-Reply-To: <6451F6631F7A4D8F8281EE7D49C49010@Dunford> References: <7EEB6ED0DAD248D1BB3DFDFE3060E1DD@hecker> <6451F6631F7A4D8F8281EE7D49C49010@Dunford> Message-ID: Remember that a DC motor has a straight line output curve on a horsepower diagram. For a given RPM there is a fixed torque output at a certain voltage. ( Horsepower equals torque times rpm.) Basically at zero RPM you have very high torque and at max rpm you have virtually no torque. To change this curve- really the slope of the straight line, the internal windings have to be changed. Gearing is a way to match the motor output to the load, in other words, change the torque output at the gearbox output. Thus, the slower locomotive with the higher gear ratio should be able to pull more cars assuming that the wheel adhesion does not come into play. Speed control via gearing change is not really the right way to look at the issue. Output torque is. For two models of the same production batch to run differently, there are some 'quality' issues within one of the models that increases its frictional losses as compared to the other model. It could be alignment of shafts, binding somewhere in the mechanism, brush to commutator issues, friction or binding within the trucks or wheel sets (is the wheel spacing correct?). The point of all of this is that when one observes a change between two models one needs to compare the gear ratios and also see if the motor was changed to determine what might be done to correct the issue. Digital controls pulse the voltage to the motor (Pulse width modulation) via the semiconductors to bring the dissimilar models into similar speeds, which makes the motor not run on the straight line curve, but to one side of the curve. Gary Rolih Cincinnati _____ From: nw-modeling-list-bounces at nwhs.org [mailto:nw-modeling-list-bounces at nwhs.org] On Behalf Of NW Modeling List Sent: Sunday, June 07, 2009 6:10 PM To: NW Modeling List Subject: Re: P2K GP30 speed? It has been my experience that in many cases two identical locomotives from the same run often operate at different speeds. Not using DCC, my solution has always been to put the faster locomotive behind the slower. That way the faster one is slowed down by doing most of the pulling of the train. Dick Dunford Blacksburg VA ----- Original Message ----- From: NW Modeling List To: NW Modeling Sent: Friday, June 05, 2009 7:55 PM Subject: P2K GP30 speed? Hi Listers, I was able to run some new engines on a friend's layout this afternoon. For the first time I ran my new Athearn N&W SD45's. They ran great! I tried a new N&W P2K GP30 and the 45's just dragged it along. It appears to run about half speed of the Athearn's. I didn't have any of my older Athearn's or PPW or Atlas to compare it to. So my question is that the P2K's will only run with other P2K's? Thanks in advance, John Hecker _____ ________________________________________ NW-Modeling-List at nwhs.org To change your subscription go to http://list.nwhs.org/mailman/options/nw-modeling-list Browse the NW-Modeling-List archives at http://list.nwhs.org/pipermail/nw-modeling-list/ -------------- next part -------------- An HTML attachment was scrubbed... URL: From nw-modeling-list at nwhs.org Mon Jun 8 13:50:13 2009 From: nw-modeling-list at nwhs.org (NW Modeling List) Date: Mon, 8 Jun 2009 17:50:13 +0000 (UTC) Subject: P2K GP30 speed? In-Reply-To: Message-ID: <2135165303.1210441244483413869.JavaMail.root@sz0005a.emeryville.ca.mail.comcast.net> Hi Gary; Your note seems to indicate that you are assuming the motor is perfect.? There are also variations motor to motor such as: ? the variability of the steel in the laminations ? the number of laminations - being off ?1 is not uncommon on low end end motors due to thickness variation of the lamination material. ? variability in the magnet material - high energy NdFeB magnets are typically ?5%; cheaper ferrite magnets can be "tuned" resulting in tighter tolerances, but less efficient motors. ? geometric variability in the magnets. For low end motors like in our model locomotives, three sigma limits of ?10% within a particular model of motor should be expected. I worked on spindle motors and voice coil motors in hard disk drives. Nigel http://www.linkedin.com/in/nigelmisso ----- Original Message ----- From: "NW Modeling List" To: "NW Modeling List" Sent: Monday, June 8, 2009 9:46:16 AM GMT -08:00 US/Canada Pacific Subject: RE: P2K GP30 speed? Remember that a DC motor has a straight line output curve on a horsepower diagram.?? For a given RPM there is a fixed torque output at a certain voltage.? ( Horsepower equals torque times rpm.)? Basically at zero RPM you have very high torque and at max rpm you have virtually no torque.? To change this curve- really the slope of the straight line, the internal windings have to be changed.? Gearing is a way to match the motor output to the load, in other words, change the torque output at the gearbox output.? Thus, the slower locomotive with the higher gear ratio should be able to pull more cars assuming that the wheel adhesion does not come into play.? Speed control via gearing change is not really the right way to look at the issue.? Output torque is. For two models of the same production batch to run differently, there are some ?quality? issues within one of the models that increases its frictional losses as compared to the other model.? It could be alignment of shafts, binding somewhere in the mechanism, brush to commutator issues, friction or binding within the trucks or wheel sets (is the wheel spacing correct?). The point of all of this is that when one observes a change between two models one needs to compare the gear ratios and also see if the motor was changed to determine what might be done to correct the issue. Digital controls pulse the voltage to the motor (Pulse width modulation) via the semiconductors to bring the dissimilar models into similar speeds, which makes the motor not run on the straight line curve, but to one side of the curve. Gary Rolih Cincinnati? From: nw-modeling-list-bounces at nwhs.org [mailto:nw-modeling-list-bounces at nwhs.org] On Behalf Of NW Modeling List Sent: Sunday, June 07, 2009 6:10 PM To: NW Modeling List Subject: Re: P2K GP30 speed? It has been my experience that in many cases two identical locomotives from the same run often operate at different speeds.? Not using DCC, my solution has always been to put the faster locomotive behind the slower.? That way the faster one is slowed down by doing most of the pulling of the train. Dick Dunford Blacksburg VA ----- Original Message ----- From: NW Modeling List To: NW Modeling Sent: Friday, June 05, 2009 7:55 PM Subject: P2K GP30 speed? Hi Listers, ??????????? I was able to run some new engines on a friend?s layout this afternoon.? For the first time I ran my new Athearn N&W SD45?s. ?They ran great!? I tried a new N&W P2K GP30 and the 45?s just dragged it along.? It appears to run about half speed of the Athearn's.? I didn?t have any of my older Athearn's or PPW or Atlas to compare it to.? So my question is that the P2K?s will only run with other P2K?s? Thanks in advance, John Hecker ________________________________________ NW-Modeling-List at nwhs.org To change your subscription go to http://list.nwhs.org/mailman/options/nw-modeling-list Browse the NW-Modeling-List archives at http://list.nwhs.org/pipermail/nw-modeling-list/ ________________________________________ NW-Modeling-List at nwhs.org To change your subscription go to http://list.nwhs.org/mailman/options/nw-modeling-list Browse the NW-Modeling-List archives at http://list.nwhs.org/pipermail/nw-modeling-list/ -------------- next part -------------- An HTML attachment was scrubbed... URL: From nw-modeling-list at nwhs.org Mon Jun 8 16:10:57 2009 From: nw-modeling-list at nwhs.org (NW Modeling List) Date: Mon, 8 Jun 2009 16:10:57 -0400 Subject: P2K GP30 speed? In-Reply-To: <2135165303.1210441244483413869.JavaMail.root@sz0005a.emeryville.ca.mail.comcast.net> References: <2135165303.1210441244483413869.JavaMail.root@sz0005a.emeryville.ca.mail.comcast.net> Message-ID: <36BDAA1D2EA745119E7DC913C9012C6F@071927350f> Nigel: I didn?t want to get into these details about DC motors because this stuff usually makes the average modeler fall asleep. The guy trained in physics or engineering enjoys the discussion and information, but to those not trained in the art it is information that they can?t readily understand. Personally, I like it. Never the less, based on my engineering experience, and you will probably agree with this, it is likely that the simple dimensional, fit and alignment issues are causing the differences between the two locomotive models. ?Make it like the print!?, is something you have probably said too. 90% of the time it is a dimensional issue. Somewhere in one model is a binding situation that is likely causing most of the trouble. The basic problem is the Chinese production lines have poor or no quality control. While the motor manufacturing line which uses some pretty definite hard tooling to product a motor which tends to limit the range of variability between motors to a rational Bell curve of performance ( Let?s not get off into this assumption!), the hand assembly line for the model itself has very limited control on quality. They build ?em. And if they run, they get shipped. Customer service will sort out the bad ones by shipping out a new one hot off the production line to replace the bad one. Gary _____ From: nw-modeling-list-bounces at nwhs.org [mailto:nw-modeling-list-bounces at nwhs.org] On Behalf Of NW Modeling List Sent: Monday, June 08, 2009 1:50 PM To: NW Modeling List Subject: Re: P2K GP30 speed? Hi Gary; Your note seems to indicate that you are assuming the motor is perfect. There are also variations motor to motor such as: * the variability of the steel in the laminations * the number of laminations - being off ?1 is not uncommon on low end end motors due to thickness variation of the lamination material. * variability in the magnet material - high energy NdFeB magnets are typically ?5%; cheaper ferrite magnets can be "tuned" resulting in tighter tolerances, but less efficient motors. * geometric variability in the magnets. For low end motors like in our model locomotives, three sigma limits of ?10% within a particular model of motor should be expected. I worked on spindle motors and voice coil motors in hard disk drives. Nigel http://www.linkedin.com/in/nigelmisso ----- Original Message ----- From: "NW Modeling List" To: "NW Modeling List" Sent: Monday, June 8, 2009 9:46:16 AM GMT -08:00 US/Canada Pacific Subject: RE: P2K GP30 speed? Remember that a DC motor has a straight line output curve on a horsepower diagram. For a given RPM there is a fixed torque output at a certain voltage. ( Horsepower equals torque times rpm.) Basically at zero RPM you have very high torque and at max rpm you have virtually no torque. To change this curve- really the slope of the straight line, the internal windings have to be changed. Gearing is a way to match the motor output to the load, in other words, change the torque output at the gearbox output. Thus, the slower locomotive with the higher gear ratio should be able to pull more cars assuming that the wheel adhesion does not come into play. Speed control via gearing change is not really the right way to look at the issue. Output torque is. For two models of the same production batch to run differently, there are some ?quality? issues within one of the models that increases its frictional losses as compared to the other model. It could be alignment of shafts, binding somewhere in the mechanism, brush to commutator issues, friction or binding within the trucks or wheel sets (is the wheel spacing correct?). The point of all of this is that when one observes a change between two models one needs to compare the gear ratios and also see if the motor was changed to determine what might be done to correct the issue. Digital controls pulse the voltage to the motor (Pulse width modulation) via the semiconductors to bring the dissimilar models into similar speeds, which makes the motor not run on the straight line curve, but to one side of the curve. Gary Rolih Cincinnati _____ From: nw-modeling-list-bounces at nwhs.org [mailto:nw-modeling-list-bounces at nwhs.org] On Behalf Of NW Modeling List Sent: Sunday, June 07, 2009 6:10 PM To: NW Modeling List Subject: Re: P2K GP30 speed? It has been my experience that in many cases two identical locomotives from the same run often operate at different speeds. Not using DCC, my solution has always been to put the faster locomotive behind the slower. That way the faster one is slowed down by doing most of the pulling of the train. Dick Dunford Blacksburg VA ----- Original Message ----- From: NW Modeling List To: NW Modeling Sent: Friday, June 05, 2009 7:55 PM Subject: P2K GP30 speed? Hi Listers, I was able to run some new engines on a friend?s layout this afternoon. For the first time I ran my new Athearn N&W SD45?s. They ran great! I tried a new N&W P2K GP30 and the 45?s just dragged it along. It appears to run about half speed of the Athearn's. I didn?t have any of my older Athearn's or PPW or Atlas to compare it to. So my question is that the P2K?s will only run with other P2K?s? Thanks in advance, John Hecker _____ ________________________________________ NW-Modeling-List at nwhs.org To change your subscription go to http://list.nwhs.org/mailman/options/nw-modeling-list Browse the NW-Modeling-List archives at http://list.nwhs.org/pipermail/nw-modeling-list/ ________________________________________ NW-Modeling-List at nwhs.org To change your subscription go to http://list.nwhs.org/mailman/options/nw-modeling-list Browse the NW-Modeling-List archives at http://list.nwhs.org/pipermail/nw-modeling-list/ -------------- next part -------------- An HTML attachment was scrubbed... URL: From nw-modeling-list at nwhs.org Mon Jun 8 23:42:57 2009 From: nw-modeling-list at nwhs.org (NW Modeling List) Date: Mon, 8 Jun 2009 20:42:57 -0700 Subject: P2K GP30 speed? Message-ID: Hi All, Thanks for the many responses to my question. I failed to mention that I only have access to a DC layout and test track. The GP30 I bought is a DC only version; so I won't be changing any CV's. I've never had the shell off so I don't know what I have inside. Oh well I guess I'll have to buy another to match it or one heck of an expensive shell to put on another chassis. As a side note I have one of the old GSB SD40-2's but it's never been out of the box so I don't know about how it runs. Take care, John Hecker P/S: Did you all see that Athearn is doing high hood SD40-2's in N&W? I saw this in their e-mail newsletter a few weeks ago.I can't hardly wait until the October release. -------------- next part -------------- An HTML attachment was scrubbed... URL: From nw-modeling-list at nwhs.org Tue Jun 9 11:54:54 2009 From: nw-modeling-list at nwhs.org (NW Modeling List) Date: Tue, 9 Jun 2009 11:54:54 -0400 Subject: P2K GP30 speed? In-Reply-To: References: Message-ID: The Athearn web site shows that they'll be producing 1627, 1632, and 1635 correctly had a high hood. 1625-1635 were N&W's only High Hood SD-40-2's. The remaining 1600 series SD-40-2's (1636-1652) and all the 6073's and 6207' SD-40-2's were low hood. Just a bit too modern for my model railroad! It be nice to have a couple of high hood SD-40's in blue (as delivered from EMD). Ed Painter; Narrows, VA currently living in Russelville AR From: nw-modeling-list-bounces at nwhs.org [mailto:nw-modeling-list-bounces at nwhs.org] On Behalf Of NW Modeling List Sent: Monday, June 08, 2009 10:43 PM To: NW Modeling Subject: RE: P2K GP30 speed? Hi All, Thanks for the many responses to my question. I failed to mention that I only have access to a DC layout and test track. The GP30 I bought is a DC only version; so I won't be changing any CV's. I've never had the shell off so I don't know what I have inside. Oh well I guess I'll have to buy another to match it or one heck of an expensive shell to put on another chassis. As a side note I have one of the old GSB SD40-2's but it's never been out of the box so I don't know about how it runs. Take care, John Hecker P/S: Did you all see that Athearn is doing high hood SD40-2's in N&W? I saw this in their e-mail newsletter a few weeks ago...I can't hardly wait until the October release. -------------- next part -------------- An HTML attachment was scrubbed... URL: From nw-modeling-list at nwhs.org Wed Jun 10 17:23:43 2009 From: nw-modeling-list at nwhs.org (NW Modeling List) Date: Wed, 10 Jun 2009 14:23:43 -0700 (PDT) Subject: Rapido Trains to offer (quasi) PM Class N&W Coach in N scale! Message-ID: <231843.83898.qm@web38708.mail.mud.yahoo.com> Get these discounted if you can, a bit pricey! http://www.rapidotrains.com/pan04z.html On the up side these look to be the best passenger cars by a wide margin in N scale. They also make a resonably stand-in for the PM class to my eye. The HO ones look pretty good, especially in terms of color. Mark Peele Catonsville, MD From nw-modeling-list at nwhs.org Sat Jun 13 19:45:13 2009 From: nw-modeling-list at nwhs.org (NW Modeling List) Date: Sat, 13 Jun 2009 19:45:13 -0400 Subject: Help with Steam Engine Decals Message-ID: <564524A6-C441-4B30-ADB0-F45C953C3D61@earthlink.net> I have recently acquired a few engines and stripped, aligned and painted them only to find that I had only one set of decals. I model the pre-WWII era and have a need for up to 20 sets of the old Champ BRH-46 set they originally released in 1991. The Microscale decals I had have disintegrated, and the Walthers set is mostly wrong. I don't want to use Duluxe Yaller either. I have a W-2 and M as well as a Y5, and a pile of Powerhouse Y3's to repaint and decal. The Powerhouse bodies need a 4-5 day soak in Lacquer thinner to get the paint off but under that is fairly crisp detail. Mark Lindsey Stuck in the 1930's From nw-modeling-list at nwhs.org Sun Jun 14 05:34:32 2009 From: nw-modeling-list at nwhs.org (NW Modeling List) Date: Sun, 14 Jun 2009 04:34:32 -0500 (GMT-05:00) Subject: Help with Steam Engine Decals Message-ID: <27412553.1244972072311.JavaMail.root@elwamui-polski.atl.sa.earthlink.net> Mark, BRH-46 shows on the Champ on-line list (bronze gold) as still available. Dave West Franklin Park IL -----Original Message----- >From: NW Modeling List >Sent: Jun 13, 2009 6:45 PM >To: NW Modeling List >Subject: Help with Steam Engine Decals > >I have recently acquired a few engines and stripped, aligned and >painted them only to find that I had only one set of decals. I model >the pre-WWII era and have a need for up to 20 sets of the old Champ >BRH-46 set they originally released in 1991. The Microscale decals I >had have disintegrated, and the Walthers set is mostly wrong. I don't >want to use Duluxe Yaller either. I have a W-2 and M as well as a >Y5, and a pile of Powerhouse Y3's to repaint and decal. The >Powerhouse bodies need a 4-5 day soak in Lacquer thinner to get the >paint off but under that is fairly crisp detail. > >Mark Lindsey >Stuck in the 1930's >________________________________________ >NW-Modeling-List at nwhs.org >To change your subscription go to >http://list.nwhs.org/mailman/options/nw-modeling-list >Browse the NW-Modeling-List archives at >http://list.nwhs.org/pipermail/nw-modeling-list/