[GregK]

I was messing about with an analogue Scalextric mini (very rare for me as I am 100% digital ...

) and I flicked the back wheels which caused the lights to briefly flicker on ...... this set me thinking.

Without power, the motor appears to be acting as a dynamo and generating a sizeable current. When the car is under power and belting along as these cars do ....... what happens to the power that is due to it's kinetic energy??

The Mini has an FF motor so I tried the normal 18k Mabuchi in a Aston Martin DBS and yes the same phenomena is apparent.

 

[RikoRocket]

In braking that power goes to resisting the forward motion, try turning the wheels of the car when not on the track and you will find they spin much more freely.

The smaller the resistance across the braids the greater the current that can be supplied by the "generator". So if you put a resistor in one of the wires to the braids then the maximum current will decrease, that means the motor does less work so its easier to turn, and that means your braking effect is less.

 

[GregK]

Reading my post again ........ I should have added that I was holding the car in my hand and spinning the rear wheels with my other hand.

So ...... could you squeeze a bit more top speed or torque out of a motor if you increase the resistivity of the wires and braids???

 

[Ian B]

Or put one car on the track, put another in the same lane push the 2nd car and the 1st will move!

 

[GregK]

Wow ..... this electrickery stuff is amazing ...

I'll try that later ....

 

[Mr Modifier]

If you increase the resistance in the wires or braids you decrease the amount of power able to reach the motor and reduce power and torque. Increasing resistance reduces voltage (which is why you need a resistor for a 3v LED between it and the 12v supply). The power that the resistor consumes generates heat in the resistor (so watch your fingers!).

If you want more power from the motor the less resistance between the power supply and the motor the better. Copper comes in various grades - the 99% or 100% oxygen free copper is best as it offers least resistance. Voltage also drops with distance but as there is such a small distance between braids and motor you are talking hundredths of a volt.

Power tapping your layout is the best way to keep power loss to a minimum.