Technogym CROSS PERSONAL, Service Maintenance Manual

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CROSS PERSONAL: Service & maintenance manual - rev. 1.1
Page 3.11
The electromagnetic field produced by the winding and the rotation of the disk will induce eddy
currents in the disk itself, giving rise to a force that tends to brake its motion. This generates the
exercise resistance.
The higher is the value of current generated from the Brake Board on the winding, the greater is the
resistance produced. Furthermore, with the same excitement of the brake, the higher is the
rotational speed of the disc, the greater is the resistance produced.
Due to the eddy currents, energy is dissipated on the brake disk in the form of heat.
The control on the CURRENT is of type CLOSED LOOP. The Brake Board calculates
the current value to send on the winding of the brake, it controls the supply with a
special driver circuit, and finally checks the actual presence on the brake circuit
through reading and A/D conversion of current signal read.
Control over the Resistance actually present on the pedals (effective user torque) is
Open Loop. The system (Brake Board) + (brake) provides no adjustment to calibrate
the resistance value produced, but only using the braking table stored in the Brake
Board. The accuracy of the braking system has a tolerance of ± 10%.
During the movement, the speed sensor detects the heads of the brake disk fixing screws, and
produces a speed feedback signal that is sent to the Brake board. The brake board will adjust s the
excitation current of the brake winding so that the speed detected by the speed sensor is equal to the
set value.
If the brake board does not receive a speed signal, which indicates that an exercise
session is in progress, the machine will not produce any resistance.
During the movement, the brake board monitors for possible malfunctions. The errors which can
occur are detailed at paragraph: 6.9. “The Brake Board has detected an error”.
In all that cases, the Brake Board interrupts the supply of current to the brake, the green LED
changes from being steadily on to blinking and sends an error message to the Display Board which
displays the “THE EQUIPMENT IS BLOCKED CONTACT TECHNOGYM TECHNICAL
SUPPORT (X)” where “X” represents the Error Code detected.