Electronic speed control
Computer-programmable speed controls generally have user-specified options which allow setting low voltage cut-off limits, timing, acceleration, braking and direction of rotation.
Generally the higher the rating, the larger and heavier the ESC tends to be, which is a factor when calculating mass and balance in airplanes.
Most modern ESCs contain a microcontroller interpreting the input signal and appropriately controlling the motor using a built-in program, or firmware.
As of 2014, a Swedish engineer named Benjamin Vedder started an open source ESC project later called VESC.
[3] The VESC project has since attracted attention for its advanced customization options and relatively reasonable build price compared to other high end ESCs.
The energy draw is usually measured in kilowatts (the Nissan Leaf, for instance, uses a 160 kW motor that produces up to 340 Nm torque ).
In others, such as the Nissan Leaf, there is only a slight "drag" effect when coasting, and the ESC modulates the energy capture in tandem with the conventional brakes to bring the car to a stop.
A motor used in an electric bicycle application requires high initial torque and therefore uses Hall effect sensors for speed measurement.
When supplied with a 1 ms width pulse at 50 Hz, the ESC responds by turning off the motor attached to its output.
Many high-end helicopter ESCs provide a "governor mode" which fixes the motor RPM to a set speed, greatly aiding CCPM-based flight.
This allows the pilot to retain control of the airplane to glide or fly on low power to safety.
The watertight structure is significantly different from that of non-marine type ESCs, with a more packed air trapping enclosure.
Most marine-grade ESCs are cooled by circulated water run by the motor, or negative propeller vacuum near the drive shaft output.
Quadcopter ESCs usually can use a faster update rate compared to the standard 50 Hz signal used in most other RC applications.
DShot is a digital protocol that offers certain advantages over classical analog control, such as higher resolution, CRC checksums, and lack of oscillator drift (removing the need for calibration).
Modern day ESC protocols can communicate at speeds of 37.5 kHz or greater, with a DSHOT2400 frame only taking 6.5 μs.
