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Bob Delbridge posted:

Thanks George!

I think when we say a motor is 12vdc that is a "nominal" voltage, could be a bit higher or lower.  I was wondering what a slightly higher or lower voltage would do to a 12vdc motor.

Hey, I haven't forgot about you and those boards I have, just been too lazy to get in touch, sorry.  I'll get with you soon.

12v DC motors run at lower voltages all the time, ask the scale folks. 

Don't forget, it the three rail world, there are various electronics that convert the AC voltage to DC and regulate the DC output to the motor.

Rusty

Rusty...I'm actually "In a world of my own" LOL!

My main "command system" of choice is battery-powered, remote-control, no power to the track.  At least my 8 steamers are all BPRC.

7 of my 8 diesels are still PS2 or ERR/TMCC/Legacy.

This question popped into my brain because of the top speed I'm seeing on my Williams brass N&W J 611, only about 45mph, using an 11.1v LiPo battery pack.

With PS2/DCS, it was running about as fast as I could ever want.  I never pushed it to the limit but I know it got over 70smph using the same Pittman motor that's in it now.  So the only difference is in the "command system".

I don't mind the 45mph, just curious as to why it runs so much faster under PS2/DCS.

This topic is pretty interesting.  It seems that the manufacturer is running these motors at some voltage over what they are rated for,maybe one of the MTH/DCS gurus knows the answer?  As for PWM affecting the speed, you can't have more than 100% duty cycle so the max speed  going to be voltage dependent, not have much of anything to do with the controller.  (Actually PWM controllers can never quite get to 100% duty cycle, more like 99.9%, so the same voltage will turn a motor ever-so-slightly faster when directly connected without a PWM controller.)

As for the motors are we sure they are 12VDC, or could they be 20 or 24V motors? I'm sure there are techs that would know this, but I don't.  

JGL

I m not sure a 12VDC rating is a limit as much as a nominal voltage for maximizing efficiency.  Not an expert in this field, but have read through some of the Mabuchi literature they have on their website that talks to characteristics of DC motors.  Speed, torque, current, power, efficiency.

Also there is a difference when pulsing a motor using a high voltage for a short period versus a low voltage for a longer period.  So despite the same effective voltage applied the resultant output of the motor would be different.  

 

Bob, most Decoders I have seen that are used with batteries for G gauge are using 18 to 24 or 30V batteries.  Especially if your decoder is using PWM.  If you want more speed go higher voltage.  2 in series would do it.   G

George,

After reading your comments I took another look at the receiver (ALPHA-3v2) from RCS and the instructions say the input can be from 7.2-18v max, nominal being 14.8vdc.

I may get a 14.8v, 2600Mah LiPo pack, but the price between it and the 11.1v packs I've been getting almost triples if I use the same vendor!!!  I'll look at other sources, but may go this route to see what happens.  It's only the "J" that is slower than I was used to (before with PS2) so I'd only need the 1 pack.

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