Bleed Resistor; A 1Mω 1500V Bleed Resistor Between The Secondary Ground And Earth Ground Is Required For Voltage Stabilization; Dynamic Brake (Db) Resistor; Dynamic Brake Resistor Overload Detection (Thermal Sensing) - Precor TRM 885.v2 Service Manual

Bleed Resistor

A 1MΩ 1500V bleed resistor between the secondary ground and earth ground is required for voltage
stabilization.

Dynamic Brake (DB) Resistor

The dynamic brake resistor is turned on to dissipate power generated from the main motor. This
can occur when the user runs at a high incline. The brake resistor must add the needed load to the
system to prevent the treadmill from accelerating from the target speed. The dynamic brake resistor
will go active when slowing to a stop if the system inertia causes the motor to generate power.

Dynamic Brake resistor overload detection (Thermal sensing)

The lower software has built in thermal sensing. This thermal sensing indicates when the brake
resistor is too hot to use.
A power time algorithm will be used to estimate the temperature of the brake resistor. The intent is
to shut down the treadmill based on this algorithm before the thermal switch opens.
When the maximum brake resistor operation time (temperature) has been reached:
Error 17 is sent to the display.

Dynamic Brake resistor detection circuit.

The DB resistor is tested on power up only. If it is not working an error 85 is thrown but the treadmill
will operate normal except if the DB resistor is needed. When the DB resistor has failed, the buss
voltage will increase until Over Voltage condition causing an error 15 event and the treadmill will
stop.
A broken thermal switch to Motor Controller wire connection will cause the same
symptoms.
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