By Flyduino.net

UltraESC 20A

Avaiable at Flyduino

UltraESC 20A Features

- Control: about 2000 steps (11-bit) (from off to full throttle), Active freewheeling (Complementary PWM)

- Rated current: 20A continuous, 40A burst (~ 20s)

- Active freewheeling (full part load fixed), regenerative braking

- Input voltage range: 4.5 to 17V (2 to 4S LiPo)

- Signal inputs: PWM (at various speeds), I ² C and USB

- Equipment: All N-FET (FET manufacturer rating 100A continuous), fast gate driver

- PCB: 4 layers, 105μm copper

- BEC: not available.

- Dimensions: (LxW) 37x16, 5mm

Further information

With good cooling (eg., cooling fins attached to FETs) more than 20A are possible. In general, the controller should be mounted in that way that it is in the air stream of the propeller.

If you want to charge the controller at its limits, you should reinforce the lower conductive tracks by soldering two copper wires (0.6-1,2 mm diameter) to the lower two power conductors as shown below:

In this way you can reduce the resistance of the conductors, this will prevent heat accumulation.

Maximum speed

The maximum speed will depend on the number of magnetic poles of the motor, as well as the timing. Generally 200,000 field speeds (rotations) are possible (depending on the engine even more). Here is a table which shows the maximum speed of the most common pole numbers:

magnetic poles: Max. rotations:
6 66666 rpm
8 50000 rpm
10 40000 rpm
12 33333 rpm
14 28571 rpm
16 25000 rpm
18 22222 rpm
20 20000 rpm
22 18181 rpm
24 16666 rpm

The equation for this is: 200000/magnetic poles*2
To calculate the actual speed of a motor applies: Motor Kv(rpm/V)* Voltage.
e.g. a motor with 1000kv does on a 3S LiPo (12.6V max) 12600rpm at zero load.


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