Precor AMT12 base, Service Manual

Page: 22 / 276

© Precor Incorporated, Unauthorized Reproduction and Distribution Prohibited by Law Page 22
AMT Base Operation
Power Generation
The Commercial AMT base is powered by a 3-phase generator that spins when the user is pedaling
the stairarms. There are 3 wires in the cable coming from the windings of the generator, connected
to the lower control module via 3 individual spade style connectors. The frequency of the AC sine
waves is determined by how fast the user is pedaling, and the voltage level of each AC sine wave
is approximately 100VAC.
The generator performs three functions in the AMT. First, by providing power to the lower control
module. Second, the generator is used to
charge the EFX’s internal battery. Lastly, one of the
generators six phase output windings is monitored to determine when the unit is in use and when
it is idle. This system also determines the stride rate by determining the operating speed (output
frequency) of the monitored generator winding.
Lower Electronics Module
The lower control module consists of an AC to DC conversion of the generator output, a distribution
of DC power supplies, a DC lift motor controller (only on open stride models), and control of workout
resistance.
DC Power Distribution:
Once the generator’s AC outputs are converted to DC, there are a number of regulated DC supplies
that power the various functions of the AMT. The first regulated DC power supply in the distribution
chain is an 18VDC supply, but only supplies this 18VDC if the user is pedaling the AMT. If the
customer wishes to add the external power option to the AMT, an external 18VDC supply replaces
the 18VDC supplied by generator power, allowing the unit to stay powered up (whether pedaling
or not).
A regulated 14.5VDC power supply charges the 12V battery.
A regulated 7.5VDC power supply is sent to the console via the data cable. The electronic circuits
in the console operate on +5V DC, however the lower control module sends +7.5V DC due to the
optional external equipment such as Fitlinxx, which may be connected to the CSAFE
(Communication Standard for All Fitness Equipment) port. By sending a higher voltage (+7.5V) and
regulating down to +5V DC, we insure that we can supply enough power to both the console and
the optional external equipment. To insure that this 7.5VDC regulated power supply is stable
enough to run all console related functions, the lower control module switches this 7.5VDC power
“ON” only after a rate of greater than 20RPM at the crankarms is detected.
A regulated 5VDC power supply and a regulated 3.3VDC power supply are used to power all the
digital logic functions of the lower control module.