Resistance System - Stairmaster 8G Gauntlet Service Manual

Resistance System

Gear Box
"Transmission"
"Speed Reducer"
Idler Idler
Sprocket Sprocket
Gear Box Gear Box
Sprocket Sprocket
Resistance is applied to the steps of the machine by use of an alternator. 12VDC power from the lower board is fed into
the alternator to control the amount of resistance it applies. The resistance system (alternator) connects the gearing
system, or gear box of the machine via a poly-V belt.
The alternator's connection pivots allowing the poly-V belt to be tensioned. Per design it should be tensioned to 40-54
lbs*inch, or 1/4 of a turn (90 degrees) of deflection. Ensure the belt is not too tight, or damage to the alternator bear-
ings or gear box housing can occur. For additional information relating to how to properly tension the belt, refer to the
Troubleshooting section.
The "engine assembly" consists of the alternator, brake and gear box. All three components are connected to the 8G
frame as shown above. Adjustments can be made between the alternator and the gear box to assist with step rate
issues. The system regulates itself via a
pulley of the gear box has a set screw so the poly-V belt can be aligned with the alternator pulley.
The brake is designed to prevent the steps from moving when the unit is off or inactive. The brake can be manually
released for troubleshooting purposes when the machine shrouds are off.
The alternator in the 8G is the same as in earlier Stairmaster models, including wiring. Wiring details are on the next
page and also in the troubleshooting section of this manual.
Drive Drive
Belt Belt
Hall Effect Speed sensor that reads the gaps on the alternator pulley. The inner
Frame Frame
Brake Brake
Gear Box Gear Box
Pulley Pulley
Speed Speed
Sensor Sensor
Alternator Alternator
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