BANBURY SCALETRIC RACING
TECHNOLOGY: Motors and Gearing
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This is a guide to how a slot car works aimed primarily at schools Key stage 2.
1/32 Scale cars nominally run with a 12 volts DC motor and a current up to one Amp. The motors Revs Per Minute range from 16000 to 24000 for 12Vdc,
reducing the DC volts applied will reduce the motor RPM and changing the DC polarity will run the motor in a different direction.
To power each lane a regulated adjustable 15 volt DC power supply is recommend, providing 2.5 amps as motors take more current to start turning.
The motors RPM is reduced by a ratio of (nominally) 3-to-1 through a simple gear train to turn the wheels with increased driving torque with essentially one of two gear layouts.
Inline: Crown gear with pinion (magnet retained, lead added to help keep guide in its slot)
Sidewinder: Spur gear with pinion (motor suspension mount, magnet removed, lead added to help keep guide in its slot)
The standard method of adjusting motor speed is with a plug in hand controller, this adds an adjustable power resistor to the 12Vdc positive supply line.
Controllers have a spring loaded wiper that rests on a separate contact pad connected only across the motor working as a brake.
Pulling the wipers lever moves it on to and across the resistor reducing the Ohm's (resistance) increasing the DC volts to maximum. Releasing the lever lets the spring return the wiper to the default brake position,
any turning motor then becomes a shorted out generator acting as a brake.
It is possible to enhance a controller by switching in additional resistors to give a three sensitivity ranges.
To limit power switching in diodes can reduce power, useful for beginners or rally type layouts.
Return to top BSR HOME PAGE
TECHNOLOGY: Motors and Gearing
1/32 Scale cars nominally run with a 12 volts DC motor and a current up to one Amp. The motors Revs Per Minute range from 16000 to 24000 for 12Vdc, reducing the DC volts applied will reduce the motor RPM and changing the DC polarity will run the motor in a different direction. To power each lane a regulated adjustable 15 volt DC power supply is recommend, providing 2.5 amps as motors take more current to start turning. The motors RPM is reduced by a ratio of (nominally) 3-to-1 through a simple gear train to turn the wheels with increased driving torque with essentially one of two gear layouts.
Sidewinder: Spur gear with pinion (motor suspension mount, magnet removed, lead added to help keep guide in its slot)
The standard method of adjusting motor speed is with a plug in hand controller, this adds an adjustable power resistor to the 12Vdc positive supply line. Controllers have a spring loaded wiper that rests on a separate contact pad connected only across the motor working as a brake. Pulling the wipers lever moves it on to and across the resistor reducing the Ohm's (resistance) increasing the DC volts to maximum. Releasing the lever lets the spring return the wiper to the default brake position, any turning motor then becomes a shorted out generator acting as a brake.
It is possible to enhance a controller by switching in additional resistors to give a three sensitivity ranges.
To limit power switching in diodes can reduce power, useful for beginners or rally type layouts.
Return to top BSR HOME PAGE