Precor AMT12 base, Service Manual

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the larger the magnetic braking force placed on the flywheel of the generator, thus providing
mechanical resistance.
The reason that Precor uses a 3-phase generator on a self-powered AMT while self-powered EFXs
use a 6-phase generator is centered in its use of Magnetic force as a resistance method.
Horizontal Resistance:
The A
MT’s horizontal braking force is achieved through the use of a drum style eddy current brake
assembly. The inner drum of the assembly has a number of fixed magnets glued to outer
circumference of the drum. These fixed magnets are considered the primary magnetic field. The
outer drum of the assembly has a copper sleeve bonded to the inner circumference of the drum.
When the outer drum moves relative to the position of the inner drum, the fixed magnets induce a
current into the copper sleeve. The current now flowing in the copper sleeve will produce a
secondary field, which will in turn repel against the magnetic field of the fixed magnets.
AMT motion detection (RPM):
This diagram shows the 3 sine waves from the generator, which the LPCA uses to supply and
distribute power throughout the system. The LPCA also utilizes a “zero crossing detector” to
determine a stride count by counting the zero crossings from 1 of the 3 sine waves coming from