Electromagnetic Brake; Speed Sensor; Power Entry Module - Technogym CROSS PERSONAL Service Maintenance Manual

CROSS PERSONAL: Service & maintenance manual - rev. 1.1
3.2.20. E
LECTROMAGNETIC BRAKE
This is an eddy current brake, consisting of a flywheel weight and a flat copper disk that rotates in
the air gap of a winding. Variations in the winding current produce changes in the magnetic field,
which in turn varies the eddy currents induced within the copper disk and hence its resistance to
"vertical" movement of the machine.
Two solenoids (cylindrical-shaped coil composed of a series of very closely wound circular turns of
a single strand of conducting material) connected in series are supplied by an adjustable direct
current generator to obtain a magnetic field of varying intensity. The inertia disk (flywheel) rotates
between the coils.
As a result of its movement, each sector of the disk is crossed by a magnetic field flux that varies
continuously, giving rise to electromotive forces within it that cause induced currents to circulate.
These currents flow in a direction which opposes the cause that induced them, i.e. the movement of
the disk inside the magnetic field. Consequently, they have a braking effect that slows down the
movement of the disk. The braking effect is intensified as the magnetic field strength of the coils
increases, and therefore with increasing speed of the disk. This operating principle also means that
when the disk is stationary the braking action will be zero.
Unlike the majority of mechanical brakes, which operate by taking advantage of attrition forces,
there electromagnetic brake has no parts subject to wear.
The winding resistance is approximately 5Ω Ohm, consequently the brake absorbs a maximum
current of 2.2 A.
3.2.21. S
PEED SENSOR
This consists of a magnetic induction sensor which detects the heads of the Electromagnetic brake
disk fixing screws.
3.2.22. P
OWER ENTRY MODULE
This is a module consisting of:
• power inlet socket;
• power outlet socket;
• fuse-holder for protecting line voltage and neutral with two 3.15A fast-blow fuses.
It is situated on the side of the rear footboard.
WARNING: The maximum current extractable from the output of power entry
module is 7A. This places an upper limit on the number of machines that can be
connected together: do not connect more than N°8 equipments with a 220Vac mains
supply and N°5 equipments with a 110Vac mains supply. If other types of machines are
connected together, the maximum number is determined by their current draw.
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