Are Tesla motors brushless?

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asked May 6, 2022 in Other-Home/Garden by 98pstarget (1,370 points)
Are Tesla motors brushless?

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answered May 11, 2022 by GrahamPolk (4,520 points)
Tesla motors are brushless motors.

Tesla, for example, uses alternating current (AC) induction motors in the Model S but uses permanent-magnet direct current (DC) motors in its Model 3.

There are upsides to both types of motor, but generally, induction motors are somewhat less efficient than permanent-magnet motors at full load.

Today, all the hybrids are powered by DC brushless drives, with no exceptions.

The only notable uses of induction drives have been the General Motors EV-1; the AC Propulsion vehicles, including the tzero; and the Tesla Roadster.

Both DC brushless and induction drives use motors having similar stators.

Brushless motors are better than brushed motors as they don't create spark and can run for longer periods of time without wearing out.

With brushed motors the brushes eventually wear out the longer the motor runs but with brushless motors they have no brushes to wear out.

Also brushed motors tend to have more power than brushed motors as well.

You can tell if a motor is brushless by looking at the nameplate on the motor or by looking at the motor stator to see if it has brushes.

The electric motor brush is a carbon piece with a copper wire attached and a spring.

A carbon brush, also known as a motor brush, is the small part of the motor that conducts electrical current between the stationary wires (stator) and the rotating wires (rotor) of a motor or generator.

The difference between a brushed motor and a brushless motor is that the brushed motor contains brushes and a commutator while the brushless motor does not contain the brushes or commutator and works on induction.

A brushed DC motor uses a configuration of wound wire coils, the armature, acting as a two-pole electromagnet.

The current's directionality is reversed twice per cycle by the commutator, a mechanical rotary switch.

This facilitates flow of the current through the armature; thus, the electromagnet’s poles pull and push against the permanent magnets along the outside of the motor.

The commutator then reverses the polarity of the armature's electromagnet as its poles cross the permanent magnets' poles.

A brushless motor, by contrast, utilizes a permanent magnet as its external rotor. In addition, it uses three phases of driving coils and a specialized sensor that tracks rotor position.

As the sensor tracks the rotor position, it sends out reference signals to the controller.

The controller, in turn, activates the coils in a structured way – one phase after the other.

DC motors can be better in some cases than an AC motor.

However AC motors are cheaper, tend to last longer and also are more powerful than DC motors.

AC motors also have better torque due to the higher voltage current they use.

The disadvantage of a DC motor is they require DC or direct current to run on and need transformers to change the voltage from AC to DC or you have to run them off of a DC battery.

Also DC motors are usually more expensive and also require brushes and commutators which can wear out overtime which adds to the cost.

DC motors have a high initial cost.

Maintenance cost is high and increased operation due to the presence of brushes and commutator.

Due to sparking at brush DC motors cannot operate in explosive and hazardous conditions.

You cannot run an AC motor on DC power directly as the motor would not have the correct current to start up and run.

The AC motor requires AC power while the DC motor requires DC power.

Although if you have an inverter that is big enough then you could plug the AC motor into the DC to AC inverter and power the AC motor off the DC power that way.

DC motors are continuous and can run for a very long time before they get too hot or wear the brushes out.

The rotation of the DC motor is accomplished by the force which is developed on a current-carrying conductor in a magnetic field.

The current-carrying conductor is connected to the shaft which is able to rotate relative to the stationary body of the DC motor.

You can run a DC motor continuous as long as it has enough power to the motor and as long as it does not overheat and until the brushes wear out.

Although it's not recommended to run a DC motor longer than a few hours or so at a time but they can run longer.

A 12v DC motor can run continuously 24/7 until the brushes wear out as long as the motor is not overloaded or doesn't get too hot.

A brushless motor can run 24 hours continuously as long as it's continuously rated although if it has a thermal shut down switch then the motor will shut down if the motor gets too hot.

If it does it usually takes longer than 10 hours and then the motor shuts down and has to cool off before it can be turned back on.

An electric motor can run for 24 hours a day 7 days per week as long as it's a continuous duty electric motor.

If it's not a continuous duty electric motor then it may only run for 10 hours or 24 hours before it gets too hot and needs to shut down.

An electric motor can work for 24 hours if the electric motor is a continuous duty electric motor.

If the electric motor gets too hot then it will shut off before it actually overheats due to a thermally protected motor switch.

So the electric motor can stay on for as long as it stays cool enough before it shuts off.

Some electric motors are rated to run continuous and can run 24/7 without shutting off for a very long time.

And then some motors may need to shut off after a 10 to 14 hours to cool down.

For DC motors they will usually overheat if left running longer than 15 hours or so and the brushes will wear out for a brush type DC motor.

But as for an AC electric motor that is brushless it will run and run until it either gets too hot or until the bearings wear out.

The bearings in an AC electric motor will most often wear out eventually after several months or years of continuous running.

But the motor itself is basically just a magnet that uses the electricity to turn the rotor and as long as power is supplied the motor can run and run and run.

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