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Discussion Starter · #1 ·
hi all! how many turns of AWG do i need to turn a standard ninco analog controller into a 35 ohms unit. thanks john.
 

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Discussion Starter · #2 ·
hi, doesn,t any body know the way to rewrap a resistor to give me 35ohms, come on some of you electronics guys that contribute to this forum. john.
 

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Probably not worth doing this with a ninco controller, the obvious answer would be a cheap parma controller.
The less obvious would be to connect a 50 ohm resistor in parallel which will drop the overall resistance (assuming your exising resistor is 55 or 60 ohm) to around 25 to 30 ohms.
 

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QUOTE (stoner @ 10 Aug 2011, 13:11) <{POST_SNAPBACK}>hi all! how many turns of AWG do i need to turn a standard ninco analog controller into a 35 ohms unit. thanks john.
Copper wire isn't suitable, you'd need a vast length of very thin wire to make 35 ohms.
Resiatance wire is more difficult to come by.
Maplin do constantan resistance wire but only in 28 AWG , that's 4.2 ohms a meter. You could measure up your resistor and work out how much wire you can get on it, If your resistor is big enough to wind 8.3 meters that'll give you 35 ohms.

Like slotcarscrapyard, I'm not sure its worth doing with that controller
 

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Rich Dumas
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Nichrome wire is what is used for controllers. Putting a fixed resistor in parallel with the variable one will lower the overall resistance, but the combination will not have a linear response. I would go for a Parma controller.
 

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Nichrome wire is what is normally used for controller resistors.
Constantan is an alternative that works well.
Either is difficult to come by.
 

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Discussion Starter · #8 ·
thanks guys, ive got a parma 45 ohms and a ninco with a 15ohm parma barrell resistor fitted[easy job], but due to severe lack of funds at the moment , i thought i could could just strip some arm wire and rewind the resistor with that or is this a complete no no for some reason. buy the way ive got huge amounts of varied coated wire for arm rewinds. thanks john.
 

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Quick back of an envelope calculation says theoretically around 300 turns of 39 AWG enamelled copper wire would give about the resistance you want.
It would have to be wound with the wire touching to get all those turns on, then rub off the enamel where the wiper runs.
Not sure how long wire that thin would stand up to a wiper rubbing on it and motor stall current is close to the fusing current.
Try it if you like but don't be surprised if it doesn't last long.

The Parma is much more practical.
 

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QUOTE (RichD @ 11 Aug 2011, 18:24) <{POST_SNAPBACK}>Nichrome wire is what is used for controllers. Putting a fixed resistor in parallel with the variable one will lower the overall resistance, but the combination will not have a linear response. I would go for a Parma controller.

Hi RichD, what do you mean by "non linear response" ?

I owe a 60 ohms Parma i fitted with 2 resistors and a 3 position iterruptor, so it makes a 60/40/20 ohms, and I'm quite satisfied with it.....i did not really saw a difference in the curves response ?
 

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Discussion Starter · #11 ·
lancia b, any chance of a simples! diagram and parts no,s ect, its got to be clear and simple ,im somwhere below moron when it comes to electrics, i would be dead greatfull if possible, just pretend youre explaining it to a 5yr old. thanks john.
 

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Bill Beggs
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QUOTE (stoner @ 13 Aug 2011, 00:14) <{POST_SNAPBACK}>lancia b, any chance of a simples! diagram and parts no,s ect, its got to be clear and simple ,im somwhere below moron when it comes to electrics, i would be dead greatfull if possible, just pretend youre explaining it to a 5yr old. thanks john.

Then you are going to end up with a bunch of parts that cost close to what a new parma Economy would cost and still not have a controller that works. Save up and just buy a new controller. Geez they are only around $30.
 

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Rich Dumas
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Blame it on Ohm's Law! When two resistors are connected in parallel the reciprocal value of the effective resistance is equal to the sum of the reciprocal values of the parallel resistors. 1/RE = 1/R1 + 1/R2
Suppose that we try to make a 65 ohm controller act like a 25 ohm controller. RE = 25 and R1 = 65 in that case. 1/R2 = 1/25 - 1/65. Therefore R2 = 40.65 ohms. The problem crops up when you squeeze the trigger more. See the chart for a comparison of 25 ohm, 65 ohm and 65 ohm with a parallel 40.65 ohm fixed resistor.



The 25 ohm controller and the modified 65 ohm controller are clearly not the same. The effect is not as drastic if you do not try to lower the effective resistance too much. I shall point out that some people like controllers like that. You should give this idea a try and see how you like it.
 

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Discussion Starter · #14 ·
hi, black3sr. slightly off course and i agree with you but i could,nt save 30 pence up at the moment, its all relative, when some people say there boracic it means they cant buy an nsr and hafto settle for a slot it. when i say i.m boracic i dont even have the money for a set of braids. hopefully the current situation cant go on for much longer. i got most of my scratch parts from usa 1/8 bore gears ect old parma pinions and i use silver steel for the axles because its all dead cheap and works. i posted a previous comment that i could have a completely new.rear end for less than £2.50 that includes copper rear brkt[scrap bin] new axle new pinion new gear new tyres new bearings add £0.99p to that if you want ball bearings rear end. other guys on the forum are helping me out big time with parts and swaps. many thanks to them. i,d rather buy slot it, ortman, nsr parts, but the hard rains. falling directly on my head at the moment. glad i got that off my chest cause i was feeling fed up this morning, thank goodness for slotforum. thanks again to the guy that have been helping me especially you [john]. all i need now is a 2nd class stamp and the morning will be wonder full. greatfully john.
 

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The simple answer is to carefully strip the wire off the Ninco resistor, noting where the beginning and end were connected, and reduce the length of it to get a reduced resistance. Clean up the wire and the resistor core of all the old coating.

Half the wire equals half the resistance. If you have a multimeter you can measure accurately for the right resistance. Attach one probe to the end of the wire, then move the other along until you get the desired resistance.

Wind the wire carefully back onto the core, soldering the ends back on where they came. Clearly with less wire you will have fewer turns but it's relatively easy to space them out.

Use a heat-resistant paint to secure it all - not epoxy.

Simple and cheap!!
 
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