How the electric brake on a saw works
Tool makers continue to add more safety and fatigue reduction features to their products. Examples abound with auto-lock switches, auto-lock switches, blade guards, and shields – just to get started. You can take a safety feature for granted just because you can’t see it: an electric brake. On the best circular saws and many other saws, an electric brake marks a premium feature. This solitary feature has saved many planks, wood floors, cords or even a finger or a toe! It is easy for a piece of wood or an obstruction to prevent the blade guard from sliding back into place after a cut. Without an electric brake, a blade may continue to rotate for 10 seconds or more on some saws. An electric brake stops the blade in approximately 2 seconds. So how does the electric brake on a saw work to keep you safe?
- The trigger reverses the electrical flow
- This type of braking uses electricity
- Mechanical brakes (rarer) stop a spinning wheel or blade almost instantly
- Electronic brakes wear out, but less than mechanical brakes
- Braking efficiency and speed may slow down over time – requiring maintenance
How does the electric brake on a saw work?
The electric brake can be technically difficult to achieve, but the mechanism is easy to explain. Really easy. Are you ready for it? It’s coming:
The flow of electricity is reversed when the trigger is released.
Yeah. It is more or less that. Reversing the electrical flow throws the motor into reverse long enough to provide the friction necessary to stop the rotating blade. As a result, the saw blade stops much faster than it would otherwise on its own. It’s easy to imagine the potential damage a blade spins for 10-12 seconds after cutting, especially with larger, heavier saws. The same danger exists with circular saws and angle grinders which can be put down while the blade is still spinning.
While some grinders have mechanical brakes that instantly stop a rotating wheel or blade, electric the brakes (which make up the majority of these systems) rely on electricity to stop the blade.
The use of saws equipped with an electric brake whenever possible reduces this danger. If you are the purchasing decision maker for your business or even just buying a tool for your own use, an electric brake is one feature you should emphasize.
How long do the electric brakes on the saw blades last?
While electric brakes don’t have the same wear and tear as mechanical systems, they can wear out over time due to brushes and other factors. In either case, it is wise to monitor how long the blade rotates after releasing the trigger. If the brake stops stopping the blade quickly, consider repairing or replacing the tool.
We also feel the need to highlight how brushless motors help slow the blades. With a brushless motor, the natural electrical friction exists whenever power is removed from the circuit. This tends to naturally slow down the rotation of the blades, even if no specific blade brake circuit exists. Because brushless motors already use advanced electronics anyway, you find that they often incorporate some sort of blade brake system to help slow a spinning blade once you release the trigger.
Don’t think of the electric brake as the first line of defense. The operator always plays this role. Staying safe on the job site starts with your state of mind. As with any tool, it is possible for this mechanism and / or the blade guard to fail. The brake only serves as a support for careful use. The electric blade brake (or electronic brake) has probably been the invisible keeper of many traders. Make sure it stays in good working order.
Now you know the answer when someone asks you, “How does the electric brake on a saw work?” We hope you will work more safely with this. If you are a pro and have any circular saw safety tips, add them in the comments below or leave a comment on Facebook, Instagram or Twitter.