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How many M cars?


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From RM Models Magazine,  Model Train Controller Ampere Limit Search ~ How many M cars? 


Circuit breakers kick in on Tomix controllers.  Kato, well it could burn out your motor.


* This is just an experiment. * In many N gauge vehicles, the amount of electricity required to drive = amperage is fixed. Generally, motor vehicles are 0.3A, lights and interior lights are 0.025A with LEDs, and recently Although it is not often used, it is said that the light bulb and interior light are 0.06A. However, depending on how the train is organized, it often works normally even in a state that seems to exceed the amperage that can be covered by the controller. As a matter of fact, how many motor vehicles (how many amperes) can be moved at the same time to reach the limit of various controllers?




Edited by bill937ca
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Interesting little test, it's actually pretty impressive how many motor units you can run with a single controller.


I'm not good with electronics though, does the controllers shut off to protect themselves or to protect the motors?

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All these controllers know is at a certain point there is too much current draw thru them. Once it’s near the Max safe current that the controller can handle they have circuit breaker systems built into them to shut things off so the controller or say a wheel set short circuiting a point does not melt down and potentially catch fire. Most all electrical things these days has some sort of over current circuit breaker built in so they don’t burst into flames if short circuit or current overdraw. Basically same concept as your circuit breakers in your house. Some breaker systems are more intelligent than others and some automatically reset, some need manual reset and some like old style fuses destroy themselves when tripped.

Modern ones now are usually a thermocouple and when too much current goes thru they deform and break the circuit. When they cool off they pop back and re-establish the circuit. Nice as they are pretty small and cheap components so put in more strategic spots now in more complex equipment so you can protect out closer to the point of a problem and not all the way back at the point of main power supply only. Each of your USB ports has a small breaker usually is case a usb cable or device short circuits and power is cut off right at the port and not further back on the motherboard where more damage could get done before a breaker is tripped.



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I've had Kato controllers overload and cut out before now, for example they do not like pairs of whitemetal locos in OO. No harm done to anything, just removed one loco and pressed reset.


They are surprisingly resilient for a controller aimed at N (and Kato's own low current draw HO). Mine is quite happy powering old Keyser whitemetal locos singly, although the motors aren't original and I've tuned the chassis to be as low friction as possible.

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