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4.9 Reel Assembly
4.9.1 General
The machines are generally fitted with the Gamesman and Starpoint types of reel assembly.
4.9.2 Gamesman assembly
The Gamesman reel assembly is a single unit comprising a blue injection-moulded frame
carrying a stepper motor, reel drum, light box and opto,
The stepper motor is fitted to the frame by means of an adjustable mounting ring and the
light box mounting has sufficient adjustment to allow use of the reel in the Horizon or Rio
machines without having to change the reel position.
Reels are mounted side by side on a mounting plate, to which they are securely fitted by
means of Snap-On fixing feet.
Electrical connection to the reel assembly is via a 14-way I.D.C. connector slotted into the
frame and held in place by a retaining pin. All connections are routed to the REEL5 control
board, which is mounted separately in the cabinet.
4.9.3 Stepper motor
Each reel is driven by a stepper motor having 48 steps and of a type identical to those used
on the MPU5 reel assembly.
The stepper motor consists of two stators each with twelve pole pairs and each with a
toroidal winding to two coils and a rotor which is common to both. The rotor consists of two
permanent magnets fixed to a common spindle, each magnet having poles to match its
stator. The second stator is rotationally offset from the first by half pole spacing (i.e. 7.5
degrees) so that by directionally energising both stators the motor has 48 stable positions.
Directional energising in this application is achieved by applying 12V D.C. drive through
switching transistors, to either the first or second winding on each stator. By changing the
sequence of the drive, the rotation of the rotor and its direction can be controlled in steps of
48 per revolution.
When stopped, one coil in each stator will be energised. In order to reduce the power
dissipation in the motor the REEL5 control board continuously switches the drive to these
two drives on and off at a frequency of 250Hz. For this reason the voltage across an
energised coil at standstill should read about 7 volts.
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