What do the first four numbers refer to with pittman 12v dc motors ?
9413 vs 8413. Thanks.
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The first two letters, if present, will be GM to indicate a gearmotor, if the letters are missing, the motor has no gears.
The "9" indicates the series.
The next number indicates the type of terminal or leads; 2 = lead wires, 4 = side terminals, 5 = rear terminals.
The next number indicates output; 1 = standard performance 3 = high performance.
The next number indicates can length; 2, 3 or 4 where 2 is shortest and 4 is longest.
The next set of numbers is specific customer order information and any custom work such as a specific mounting thread, etc, etc…
Pat
Yep, I guess that means my 9433F686 motors are a pretty decent buy at around $9/ea a couple years back! 
Would changing a 12 volt pittman to a 24 volt pittman give you better low speed control ?
This would be for Sunset C449W's made back in 1998-99.Thanks.
I would say unlikely. You need X amount of torque to move a train. You would just have to use a higher voltage to reach that torque. Top speed will be less for sure.
Pete
@nikko posted:Would changing a 12 volt pittman to a 24 volt pittman give you better low speed control ?
This would be for Sunset C449W's made back in 1998-99.Thanks.
This will all depend on how you run it, how it’s geared, and what if any control system you are or intend to use,…..we’ll need more information….
Pat
@nikko posted:Would changing a 12 volt pittman to a 24 volt pittman give you better low speed control ?
This would be for Sunset C449W's made back in 1998-99.Thanks.
yeah it does
If you're looking for a simple fix, try a few diode pairs in series with the motor. Truthfully, I doubt you'll be happy with the result of just changing the motor.
@nikko posted:Would changing a 12 volt pittman to a 24 volt pittman give you better low speed control ?
This would be for Sunset C449W's made back in 1998-99.Thanks.
Yes it would, for a couple of reasons. First: for any given change in input voltage, the change in motor RPM will be smaller. (The "slope" of the speed-voltage curve isn't as steep.) You can use a wider range of travel in the transformer lever, or more "speed steps" in your command decoder. In a sense, the steps end up closer together which gives more precision.
More importantly, the "step-off" or breakaway will be gentler, and this is why: Let's say you are starting a heavy train with the slack stretched. With the loco in forward, as you advance the throttle, but before it actually starts moving, the motor is effectively stalled and drawing a lot of current. Depending on how well-regulated your power supply is, this current draw reduces the total voltage in the circuit. So you keep advancing the throttle... As soon as you reach the threshold where motor torque is sufficient to overcome static friction, the loco and train will move. The loco may surge unrealistically. Not only because the torque required to overcome rolling friction is less than that required to overcome static friction, but also, as soon as the motor starts turning it draws less current than it did a second ago when it was stalled. So even if you don't continue to increase the throttle, the power supply is unloaded and there's more voltage on the track! That difference between stall current and rotating current is smaller with a 24-volt motor, so the aforementioned increase in circuit voltage is less. And, the 24V motor is half as sensitive to slight changes in voltage! So the starting behavior is gentler, more train-like. Don't take my word on this. Get yourself an ammeter and a voltmeter, connect them both to the track feed, and see for yourself!
Now- if you've already upgraded your Dash-9 with a speed control system, depending on how it's tuned, whether the gear train is self-locking, the gear ratio, etc., the effect of a 24V motor upgrade may be subtle, but still beneficial. I did most of my experimentation circa 1994-2000, before speed control was available in 3-rail O gauge. When I swapped in a 24-volt motor, I saw a performance improvement every single time. The locos that had poor (i.e., too fast) gearing demonstrated the biggest improvement, and that describes about 95% of all the O-gauge locos ever made. My $.02, YMMV.
One down,three to go.The overall performance with the sunset,1998 GE dash 9,is night and day now that the 12v pittman can motor has been replaced with a 24v,same series-size pittman.Slow speed is perfect and so is normal scale speed.Starting slow speed,7v at.4a VS 9v at 1a.Normal train speed is 12v-14v at .8a-.9a.Extreamly happy,only MTH Z4000 with no speed control.So much more realistic with 24v motor.
@nikko posted:One down,three to go.The overall performance with the sunset,1998 GE dash 9,is night and day now that the 12v pittman can motor has been replaced with a 24v,same series-size pittman.Slow speed is perfect and so is normal scale speed.Starting slow speed,7v at.4a VS 9v at 1a.Normal train speed is 12v-14v at .8a-.9a.Extreamly happy,only MTH Z4000 with no speed control.So much more realistic with 24v motor.
Question will be when you pull a string of cars, ……and are you strictly running conventional, with no command or cruise features?….some of us actually look for that 1 amp draw, …..the amp is the torque, ….and torque is what gets the train moving, ……while less than 1/2 amp is great, will you be able to get the power out of it to do the job the locomotive is supposed to do?…..I’ve tested about every conceivable Pittman option in large, O scale steam, and my observations have been the higher the voltage range, the less torque I had at lower voltages, and some stumbling handling a train…..this may be apples & oranges, as I’m testing in a command environment,……
Pat
Pat I did my testing on "home-sized" layouts. Pulling about 15-17 plastic cars I never got anywhere near the peak or stall torque of these motors.
Looking at the Pittman spec sheet, I'm pretty sure that the 12- and 24-volt windings of a given motor, for example Pittman 9433, have the SAME stall torque. But the 24V motor develops it at half the amperage. So you don't really get less torque out of the higher-voltage winding. In any case there's more than enough to pull the train, and starting behavior is more realistic.
Lionel consulted with Pittman when they were developing the Odyssey System circa Y2K. Pittman advised them to go with a higher-voltage winding. They ended up choosing 15V because they knew the speed control system would keep 3-4V in reserve, and were perhaps concerned that zoom-zoom toy train guys would complain about a lack of speed. If they didn't need that buffer for speed control, I'm pretty sure they would have chosen a 19V winding, which would be a great choice for conventional operation. A 19V motor would make a great upgrade for most people, but 24V motors seem to be more readily available in the secondary market.
When a tach sensor is used to detect movement / RPM, the rated voltage make much difference in the starting behavior. However, if the speed control system relies on back-EMF and it's not tuned for a 24 volt motor, then I suppose that could cause stumbling. Like I said, I was testing mid-to-late 1990s locos with PS1, QSI, and Dallee reverse units, before speed control was offered in 3-rail O.
One of the things I don't like about a lot of the speed control systems is that the motor sometimes feels "over-controlled" and robotic. This can be true of starting AND stopping. Proper gearing and a carefully-spec'd motor will produce reasonable control of train speed, a decent continuous slow speed, and realistic train handling. Folks in other scales have enjoyed realistic operation for years without speed control, and many still do.
The only downside to a higher voltage winding: as you know, unless you're willing to put 24V on the rails (which I DON'T advise), you will give up some top speed. IMO on home-sized layouts with short straightaways, 50-60 mph is fast enough! I'm glad Nikko took my advice, and he got to experience the benefits for himself.
All 4 Sunset GE's are now finished w/pittman 24v motors,#8314.All 4 w/25 car train 8.5v @ 2.6a slow speed and 12v-14v @ 3a normal speed.I'm very pleased with over-all performance and time spent on these.Thanks to all of you.
@nikko posted:All 4 Sunset GE's are now finished w/pittman 24v motors,#8314.All 4 w/25 car train 8.5v @ 2.6a slow speed and 12v-14v @ 3a normal speed.I'm very pleased with over-all performance and time spent on these.Thanks to all of you.
That’s great news, let’s see a video of your repowered engines at work!!
Pat
For comparison here is a 3rd Rail E7 with a 12v 9234 Pittman.
Pete
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Videos (1)
@Norton posted:For comparison here is a 3rd Rail E7 with a 12v 9234 Pittman.
Doesn't that one have ERR Cruise Pete? 
Amps through a motor do not equal torque. For two motors of equal voltage rating, current matters, sure.
But for motors with different windings, you can't simply use current to compare.
@nikko posted:All 4 Sunset GE's are now finished w/pittman 24v motors,#8314.All 4 w/25 car train 8.5v @ 2.6a slow speed and 12v-14v @ 3a normal speed.I'm very pleased with over-all performance and time spent on these.Thanks to all of you.
Any plans for your 12v Pittman motors? If you want to offload one or a couple I might be interested.
@rplst8 posted:Amps through a motor do not equal torque. For two motors of equal voltage rating, current matters, sure.
But for motors with different windings, you can't simply use current to compare.
I’ll correct you Ryan on one thing, the amp draw of a motor can be a direct link to torque value, ….the amps being drawn are a direct link to the work being performed……..often, people relate the amp draw as a consumption of power to do a task, but it also can be used to equate the power being delivered, and in the case of our models, where the amp draw is in relation to gcm, …(grams per centimeter)
Pat
@gunrunnerjohn posted:Doesn't that one have ERR Cruise Pete?
They do John. This was posted only to demonstrate that 12v motors can run pretty slow too. Maybe not slow enough for Nikko but plenty slow for me.
Pete
@Norton posted:They do John. This was posted only to demonstrate that 12v motors can run pretty slow too. Maybe not slow enough for Nikko but plenty slow for me.
Yep, I'm perfectly happy with cruise.
