The Sawstop Safety System - SawStop JSS-120A60 Owner's Manual

THE SAWSTOP SAFETY SYSTEM

The Jobsite Saw Pro is equipped with the SawStop safety system.
This revolutionary technology was developed to reduce the potential
for a serious injury in the event of accidental contact with the saw
blade.
The SawStop safety system includes two components, an electronic
detection unit and a fast-acting brake. The electronic detection
unit detects when a person contacts the blade. A small electrical
signal is induced onto the blade by electrodes placed around the
arbor. Although this low voltage, high frequency signal is too small
to feel, it can be measured by the detection system. When human
skin comes into contact with the blade (or arbor), a portion of the signal is absorbed by the body due to the
inherent electrical capacitance of the human body. As a result, the signal on the blade gets smaller and the
detection unit recognizes this as contact.
Wood and other non-conductive materials such as plastic, foam, cardboard, Corian, melamine, etc., do
not cause a drop in the signal because those materials do not absorb the signal on the blade. Conductive
materials such as aluminum and other metals, carbon fiber materials, mirrored acrylic, carbon-filled
materials, etc., will typically cause the brake to activate. If you need to cut these conductive materials, the
safety system can be placed in "Bypass Mode" to temporarily disable the brake. (see page 50).
The fast-acting brake includes a small fuse that holds a strong spring in compression. If the electronic
detection unit detects contact while the blade is spinning (including during coast down), the fuse is burned
by a surge of electric current. The spring then pushes an aluminum pawl into the teeth of the spinning
blade. The teeth cut into the pawl, stopping the blade. The total time between the detection of contact and
stopping the blade is just a few milliseconds. If the brake is activated while the blade is at or near full speed,
the blade will also quickly retract below the table. The system will not activate the brake when the blade is
stopped–even if you spin the blade by hand. This allows you to touch or change the blade when the motor
is off just as with ordinary table saws. However, for safety, always turn the main power switch to OFF and
unplug the power cord when changing the blade.
The SawStop safety system is active whenever the main power is on. The safety system continuously
performs many different self-checks to ensure that the components of the system are operating properly.
If any problems are detected, the safety system will disable the motor and display a system status code
to help you identify and correct the problem (see page 45). If the problem is detected while the motor is
spinning, the motor will be shut off. The safety system will not allow the motor to start, even in Bypass Mode,
as long as a problem is detected.
The electronic detection unit and fast-acting brake are contained in the "brake cartridge," which is
positioned under the table and just behind the blade, as shown above. The brake cartridge must be correctly
installed before the motor can be started (see page 34). In the event that the brake is activated, a new
brake cartridge must be installed before the saw can be used again.
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SawStop Jobsite Saw Pro