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Post by steveturner on Oct 19, 2015 11:09:34 GMT -8
Guys i have couple of can motors for a project i am doing.They start up too fast on the throttle.Is there a way of slowing them down so they are not so fast at beginning of throttle movement. Not a biggy i can get another motor but if there is away such as resistors or whatever to slow start up i wouldnt mind learning about it. I ordered some Mabuchi motors with same model number as previouly i had but for whatever reason they are not same speed as my previous purchase though model number same. I ordered Mabuchi motor FK 130-sh my previous order the motors were perfect speed on throttle, new ones to fast off the throttle. I guess i dont understand motor terminology though model numbers were the same.Thanks Steve
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Post by mlehman on Oct 19, 2015 12:25:26 GMT -8
DC or DCC? Just checking, although I'm guessing DC?
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Post by atsfan on Oct 19, 2015 12:28:47 GMT -8
What is the project? Gearing an option?
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Post by steveturner on Oct 19, 2015 12:39:47 GMT -8
DCC guys ,Motor application steam loco cup and dogbone. Dont want to use cvs to slow down motor or fine tune it unless its fairly good application to start with. I was pretesting motor with DC power pack and compared it to other motors. I usualy break motor in and oil bearings and run both directions DC for a bit.The motor has too many RPMS at low throttle movement.I was hoping to decrease this. It probably is usable but i will not be moving throttle to far.All part of the fun of tinkering with projects LOL Steve
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Post by atsfan on Oct 19, 2015 12:42:41 GMT -8
Increasing resistance on the input will lower the input power. So yes it will run slower undee less power.
There probably is a minimum starting voltage you will need to still reach though to get the motor to turn over at all.
I say gearing or CV would be simpiler though....
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Post by mlehman on Oct 19, 2015 12:51:10 GMT -8
Steve,
Just a whole lot easier to use the CVs to adjust for something like this. DC solutions tends to be kludges for this sort of thing. The resistor would need to be rated at least 1 watt and then might still get hot. I hate melted models.
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Post by steveturner on Oct 19, 2015 13:01:40 GMT -8
Ok.I will hook up to a decoder on bench and see what i can do with motor speed. This is new territory for me so we shall see what happens.Thanks for the input.Steve
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Post by Mark R. on Oct 19, 2015 16:39:42 GMT -8
What kind of DC throttle are you using for testing ? If you are using an older rheostat type, they will not control high efficient motors very well. IF that is the case, try using a transistor throttle as they can regulate the voltage much better.
Your DCC system is entirely different again as it doesn't feed a variable DC voltage to the motor, but rather varying spikes of full voltage (pulse width modulation). With CV2 (start voltage) set to 0, and your motor still runs too fast at speed step one, you can't adjust it any lower than that.
Mark.
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Post by mlehman on Oct 19, 2015 16:58:10 GMT -8
SNIP With CV2 (start voltage) set to 0, and your motor still runs too fast at speed step one, you can't adjust it any lower than that. Mark. Now here is one place where the resistor might help some, although the results may still result in too much heat. The problem with higher wattage resistors is that they're bigger. Sort of a bad combination with a tiny motor, but depends on your application, room available, and probably most of all the top speed you intend to run. If low, then it might just work, but if you want control up to full speed, it's gonna be tough. |
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Post by Mark R. on Oct 19, 2015 19:17:12 GMT -8
I've never actually tried it .... how would a resistor affect the PWM and BEMF ?
Mark.
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Post by steveturner on Oct 19, 2015 19:34:53 GMT -8
Ok i hooked motor up to a Decoder.Low speed fine.................it attains top speed to fast ,not much movement of throttle. Maybe cvs could adjust that?.I will have to think about that and maybe try a speed curve on Decoder Pro. Good motor maybe just not the correct one though i am sure folks have used this motor. I dont understand if they are marked the same model number on can how they can be so different. Steve
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Post by jonklein611 on Oct 20, 2015 2:30:34 GMT -8
Ok i hooked motor up to a Decoder.Low speed fine.................it attains top speed to fast ,not much movement of throttle. Maybe cvs could adjust that?.I will have to think about that and maybe try a speed curve on Decoder Pro. Good motor maybe just not the correct one though i am sure folks have used this motor. I dont understand if they are marked the same model number on can how they can be so different. Steve Speed tables are your friend. (even just playing with Vstart Vmid and Vmax might work) |
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Post by bnsf971 on Oct 20, 2015 2:46:53 GMT -8
Ok i hooked motor up to a Decoder.Low speed fine.................it attains top speed to fast ,not much movement of throttle. Maybe cvs could adjust that?.I will have to think about that and maybe try a speed curve on Decoder Pro. Good motor maybe just not the correct one though i am sure folks have used this motor. I dont understand if they are marked the same model number on can how they can be so different. Steve Try setting cv5 to 255, and cv6 to 50, and see how that works. Tweak cv5 downward for lower top speed, and cv6 down for lower starting/midrange speed, and up for higher. |
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