We are building a Surveying vessel using 4 T200 thrusters. To keep the electronics compact, we are planning to use a T Motor 4 in 1 ESC to control the 4 motors. From the forums and learning material on Blue Robotics BasicESC, I understood that the Blue ESC uses the One Shot 125 protocal and uses a BHeli Firmware. The T-Motor ESC supports not only One Shot but also the newer DShot protocol. My questions are:
If this ESC is suitable to be used with the T200 Motors?
Does the ESC protocol have any influence on the performance of T200 Thrusters?
Is the bidirectional nature of ESC comes from the firmware used or the ESC hardware itself?
What other requirements should I keep in mind while selecting the ESC?
That depends on how you’re powering it and how hard you’re intending to drive the motors. From the T200 Technical Details, a single thruster with a 16V power supply will draw 24A of current at full throttle. The page you’ve linked to says the ESC is capable of handling 45A, so you could handle 2 T200s with it at almost full throttle (assuming a 16V supply). If you’re using 10V then the max current is down to ~13.7A, so you could run 4 at almost full throttle, but you wouldn’t have very much thrust (just 55% of the thrust you can achieve with a 16V supply).
If you were hoping it would allow full throttle for all 4 thrusters then it’s unfortunately not suitable.
The input protocol tells the ESC what speed to use, so some protocols might be able to change speed with more fine-grained control, but it shouldn’t have an effect on the actual thrust the thrusters can output (that’s determined by the thrusters themselves, and the ESC firmware and hardware, and its power handling capacity).
Brushless DC motors are controlled by activating coils in a particular order, so they act as electromagnets that magnetically push/pull the rotor around. If you swap any pair of the wires going into the motor it will turn in the opposite direction - it’s the order that the coils are activated in that determines the spinning direction, so bidirectional control is a firmware option (although not all firmware types will support it).
The main components are:
an input method you’re able to support (e.g. ArduSub uses PWM control for the motors)
feature set suitable to the motors you’re driving and control you require, e.g.:
Note that our Basic ESC is a separate product to the (retired) Blue ESC. Our Basic ESC does use a BLHeli firmware, and we usually control it using PWM inputs (1100-1900us pulse duration).
If it’s helpful, our Basic ESC firmware settings are available in the ESC Technical Details, but note that they may not be suitable for all BLHeli ESCs for use with our thrusters (some ESCs have a lower current rating), and non BLHeli ESCs will require similar settings but they may not be exactly equivalent.
Thank you very much Eliot for your detailed response and links to useful resources. I checked again the 4 in 1 ESC and it seems it can do 45A for each motor and not overall. So it might be sufficient. I will buy it and give it a try some day and report back on the forum with my results.
Just a note, ESCs designed for multirotor use are usually current rated assuming that there is strong prop wash actively cooling them at all times, which will likely not be the case in your application. I suspect you may have to add a fan or heatsink to get it to run reliably at high throttle.