Power Supplies; Logical Ride-Through Power; Processor Board Connectors; Isolation Transformer - GE T2100 Service Manual

Power Supplies

Logical Ride-Through Power

Processor Board Connectors

Isolation Transformer

Elevation Relays

Revision A
Theory of Operation: Power Board (PCB) Theory
There are two identical power supplies. One is for the microcontroller
power and the serial link, the other is for signal interface to the control
drive. The isolated serial link supply provides 5-volt power to operate a
manual controller and the control circuitry on the processor board.
Unregulated power for the isolated power comes from the center tapped
isolation transformer, the non-isolated power comes from the 24V power
supply. These are both fed through the full-wave bridge to the switching
regulator.
The switching regulator is a step-down, buck PWM-type that switches at
about 100 KHz. It also has an internal current limit of 4 amps. The 5-volt
regulators are configured to produce about 5.1 volts.
Located on the power board are 3 Ultracapacitors. They are fed by the
isolated switching power supply. These capacitors provide 3.3 Farads of
capacitance that give the processor board power to logically power down
activities in case of a loss of power to the GE T2100 Treadmill.
The power board has two connectors that directly interface with the
processor board. The first, a 3-pin power connector provides +12V
Unregulated power, +5V isolated power and isolated ground to the
control side of the processor board. The 10-pin ribbon cable provides a
signal interface 24V power, as well as +5V non-Isolated power and a non-
isolated ground connection.
The isolation transformer provides isolation for the secondary. The 220
VAC primary is stepped down and isolated from the 12V (CT) secondary.
The secondary provides +12V unregulated power for a 5-volt switching
supply.
A direction control and an enable relay control the elevation motor. A
change in direction should only occur when the elevation motor is
stopped. The enable relay is disabled by the normally-closed limit
switches at the end of travel to prevent damage to the motor. The
LIMIT* signal goes low when a limit switch is activated in a particular
direction.
GE T2100 Treadmill
2021403-031
5-5