There are two main types of AC motors used in table saws and three different designs for how the power is transferred from the motor to the arbor that turns the saw blade. The two types of AC motors are:
- Universal motors (aka commuter motors)
- Induction motors
The three different designs are:
- Direct driven setup
- Belt driven setup
- Worm drive setup
Direct-Drive Table Saw Motors
Direct-drive table saw motors refer to any motors where the drive shaft is connected directly to the arbor that turns the saw blade. Direct-drive setups most commonly use universal motors and are in saws that are marketed towards beginner and intermediate users because of their affordability.
Universal motors can work with both AC and DC power sources, but for most table saws, these run on AC power.
The power is generated from a rotor that is housed inside the stator. When a current is applied to the
The benefits of using a direct drive motor are:
- Direct drive motors have a lower manufacturing cost
- Direct drive motors produce a higher torque to power ratio
- Direct drive motors are relatively small and compact
Universal Motor Table Saws
Universal motors are an incredibly common type of motor that is used in many different tools including household vacuums, pressure washers, hair dryers, box fans, and table saws. As mentioned above, universal motors are most commonly used in a direct-drive setup, where the motor’s drive shaft is connected directly to the table saw’s arbor.
Induction Motor Table Saws
Induction motors are almost unseen in entry-level table saws. They’re larger and much heavier than a universal motor. However, the biggest difference from a universal motor is the cost. Induction motors are much more expensive to produce; however there are some good reasons for the price difference.
The benefits of an induction motor, when compared to a universal motor are:
- Induction motors last longer because of less moving parts and less heat generation
- Induction motors are quieter, as they take slightly longer to reach full speed
- Induction motors are more efficient due to their design. They generate less heat and do not utilize brushes
Induction motors are commonly seen in high-end cabinet table saws like SawStop, Grizzly, Powermatic, and others. The people who use these types of saws are typically in a production environment or scenario where the saw is running for several hours a day, every day. These demands require an induction motor that can do the job.
Belt-Drive Table Saws
Belt driven table saws refer to any table saw where there is an intermediary belt between the saw’s arbor and the motor. Belt-driven setups are most commonly used with induction motors. Because of their size and weight, induction motors are typically located lower on the table saw and then connected to the arbor via a belt.
The only real downside to a belt-driven setup, assuming it’s using an induction motor, is the cost and occasional belt replacement. Induction motors are more expensive than a universal motor, but will significantly outlast the latter. Belts are relatively inexpensive and are essentially negligible for the lifespan you’ll get out of the motor.
Worm Drive Table Saws
A worm drive table saw refers to a design where a worm gear is used to drive the arbor on the table saw. The primary benefit of using a worm drive is increased torque, which results in more power that will aid in cutting through thicker or denser material. Naturally, this has a relationship with the size of the motor the worm gears are connected to, but in general that’s the goal.
Additional gears for this setup add weight to the part, which could be good or bad depending on your perspective. Bad for portability, but good for overall stability.
Currently, SkilSaw is the only company that uses a worm drive design. Based on drawings for replacement parts, the motor appears to be a universal motor as it uses a set of brushes.
What table saw motor is best?
The best setup for you will depend heavily on your use. Budget aside, frequency and intensity of use will be the largest factors. For a commercial set up or frequent use several days a week, an induction motor is a must.
Induction motors are built to withstand a commercial environment and can be easily replaced after tens of thousands of hours. Induction motors have a NEMA classification so the size, mounting holes, shaft, and other characteristics are standardized across that NEMA class.
For the average DIYer or homeowner that does some weekend projects from time to time, almost any consumer level table saw will do the job. These table saws are equipped with direct drive, universal motors. The brushes on these saws will wear out over time, but aren’t too difficult to replace.
The brushes actually aren’t brushes at all. They’re actually prices of graphite that are spring loaded so that as they wear down, the spring continually pushes the graphite into the commutator for a constant connection.
