Maintain your Scalextric car's RX motor with these simple hints and
tips
Abstract
The earlier Scalextric cars produced in the 1960s were fitted with
open frame motors the most common of which is known as the RX motor.
A motor similar to this was also fitted to many of the Hornby locomotives of the
period. This article shows how an RX motor can be serviced in a methodical
way by considering the mechanical, electrical and magnetic aspects of
the motor.
Introduction
The
RX
motor was fitted to most Scalextric cars from the 1960s. In order
for your Scalextric car's RX motor to give the best possible performance
it has to be in the best possible health. Effectively giving the maximum
torque for the electrical power available to it. For any electrical
motor to give its best 3 key areas need to be considered; the mechanical
condition of the motor, the electrical condition of the motor and the
magnetic condition of the motor.
Mechanical
Mechanically the RX motor needs to be in the best condition possible
to ensure that no energy is lost and the motor can transfer all of the
generated torque to the rear axle. To do this several areas need to
be reviewed:
- Firstly check and ensure that all the parts are present and undamaged.
All missing
or damaged parts must must be replaced.
- Check and ensure the motor armature spins freely with no rubbing
or tight spots. This could be caused by missing or damaged bearings
or a damaged / deformed motor housing.
- Inspect the motor brush
holder for damage and replace if necessary.
- Review the motor pinion gear and ensure all the gear teeth are in
good condition. Replace the pinion gear if gear teeth damage is found.
- Add a drop
of oil to each of the bearing felt pads.
- Ensure the brush
spring sleeve is present and in good condition. Replace if necessary.
Electrical
There are many electrical connections and contacts used on the RX motor.
Each of these must be in good condition to ensure the best performance
of the motor. To do this several areas need to be reviewed:
- Firstly check and ensure that the solder joint between the wire
from the pick-up brush and the eyelet that fits over the brush
spring sleeve is complete and sound. Replace
or remake this joint if any of the wire strands are broken or
not making contact.
- Inspect the eyelet
for any dirt or metal oxides that may have formed over the years.
Clean the brush spring back to clean shiny metal where it contacts
the motor brush.
- Inspect the brush
spring for any dirt or metal oxides that may have formed over
the years. Clean the brush spring back to clean shiny metal where
it contacts the motor brush and the screw that secures the magnet.
- Inspect and clean the motor
brushes removing any dirt, oil and carbon deposits. Ensure the
carbon block is present and securely attached to the brass strip.
Clean the motor brushes back to clean shiny metal where they contact
the brush spring and eyelet.
- Remove any dirt, oil and carbon deposits from between the commutator
segments of the armature.
- Remove any dirt, oil and carbon deposits from the commutator.
- Check the three solder joints that secure the armature windings
to the commutator, remake these joints if necessary.
- The electrical connections for a car with an RX motor are:
- Contact: Track braid to track rail
- Contact: Braid contact to track braid
- Solder joint: Wire to braid contact
- Solder joint: Motor brush sleeve to wire
- Contact: Motor brush to motor brush sleeve
- Solder joint: Motor brush carbon block to motor brush
- Contact: Commutator to motor brush carbon block
- Solder joint: Armature wire to commutator
- Solder joint: Armature wire to commutator
- Contact: Commutator to motor brush carbon block
- Solder joint: Motor brush carbon block to motor brush
- Contact: Motor brush to brush spring
- Contact: Brush spring brass bolt
- Contact: Brass bolt to eyelet
- Solder joint: Eyelet to wire
- Solder joint: Wire to braid contact
- Contact: Braid contact to track braid
- Contact: Track braid to track rail
Magnetic
The magnetic field used by the RX motor is provided by a
permanent
magnet at the rear of the motor. The magnetic field reaches the
outside of the armature by the use of steel plates that are also used
as the housing for the motor. To ensure the magnetic circuit is maintained
the RX motor uses various materials to ensure the magnetic field is
not reduced. Over time the magnet can lose some of its magnet field
strength thereby reducing the motor's torque and top speed. A replacement
Neodymium
magnet is available to restore and improve the RX motor's performance.
- Ensure the magnet is secured by the correct brass screw.
- Ensure both the steel housing plates make good tight contact with
the magnet.
- Ensure the aluminum plate adjacent to the magnet is fitted correctly.
- Ensure the brass plate at the commutator end of the motor is fitted
correctly.
General
Through experience we have found that some RX motors still do not perform
well even with all of these checks completed. This may be caused by
a weak magnet or internally damaged armature windings. These faults
are outside the scope of this article. There are many other possible
faults with the earlier cars with the open frame motors. This is intended
as a simple fault finding guide only. If the information above does
not resolve the fault then contact us for further information.
About the author:
Gary Harding has been working with Scalextric cars for over 30 years
and now operates Scalextric Car Restorations in the UK. Scalextric Car
Restorations is a Worldwide internet based business that offers for
sale high quality Scalextric cars and Scalextric parts from the 1960s
to the present day. All the restoration work is carried out to the highest
standards with the highest quality parts available. Only the best cars
are selected and the final result is a car that is genuinely like new.
Further help and advice relating to this article or Scalextric cars
in general can be found at:
http://www.scalextric-car.co.uk
