Tread-Belt Motor Drive; Mechanics; Controls - Technogym Forma Service Maintenance Manual

FORMA: Service & Maintenance manual - rev. 3.0

3.2. TREAD-BELT MOTOR DRIVE

3.2.1. M
ECHANICS
The tread-belt is actuated by the motor through a linkage consisting of the motor pulley, the driving
roller and the belt which connects them. In this way, a given belt motor speed corresponds to a
predetermined linear tread-belt speed. The belt motor is controlled by the inverter which generates a
variable-frequency sine wave signal: variations in frequency cause the motor speed and hence the
tread-belt speed to vary.
3.2.2. C
ONTROLS
To start the motor, the CPU board sends a Start signal to the inverter through the driver board,
enabling the inverter to drive the motor. After outputting this enable signal, the CPU board sets the
motor speed by sending a PWM signal to the driver board, which the driver board converts into an
analog input voltage to the inverter. The relationship between the analog input voltage and the
inverter output frequency is determined by the values of the configuration parameters in the inverter
program.
During its movement, the inverter checks the motor and, if any problems are detected (overvoltage,
overcurrent, SW and HW problems to the inverter, etc.) it halts the motor and sends an alarm signal
to the CPU board, which displays the error message "E3".
To protect the motor from overheating, each motor phase has a thermal cutout connected in series. If
the temperature exceeds the threshold value, the thermal cutout opens and interrupts the circuit. The
inverter detects this condition as the opening of a NC external contact. In such a case the inverter
halts the motor and outputs an alarm signal to the CPU board, which displays the error message
cited above.
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