SawStop CNS175-AU - Manual (Page 13)

SawStop 10” Contractor Saw 11
The SawStop Safety System
This contractor saw 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. SawStop ® saws are
the only saws smart enough to know the difference between you and the wood you are cutting.
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.
(The Bypass Mode is discussed on page 55.)
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 identify the problem (see
page 44 for a description of the system status codes and the corrective action). 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 59 for instructions on removing and installing the brake cartridge). In the event
that the brake is activated, a new brake cartridge must be installed before the saw can be used again.
®
Brake Cartridge