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When developing underwater drones (ROVs/AUVs) or marine exploration robots, the stability and waterproof reliability of the propulsion system directly determine the success of a mission.
In this tutorial, we will guide you step by step on how to properly connect and configure CubeMars Underwater TW Series ESCs (Electronic Speed Controllers) with compatible underwater thrusters.
Through this tutorial, you will learn the essential wiring standards, throttle calibration logic, and safety testing procedures before deployment, helping your underwater robot achieve powerful and reliable propulsion quickly.
Before starting the wiring process, make sure you have prepared the following hardware and tools:
Core Hardware: CubeMars Underwater TW Series ESC,Compatible underwater thruster
Power System: Battery pack with matching voltage (such as lithium battery),Power connectors
Control System: Flight controller, receiver, or underwater main controller that supports PWM signal output
Auxiliary Tools: Waterproof insulation tape,Heat shrink tubing,Screwdriver,Multimeter (for checking short circuits)
Wiring in an underwater environment must be extremely precise. Even a small short circuit or poor connection may cause equipment failure.
Please follow these three core connection principles:
Power Connection (Power Input): Connect the positive terminal (VCC) and negative terminal (GND) of the battery pack securely to the power input terminals of the TW ESC. Warning: Always use a multimeter to confirm the positive and negative terminals. Never reverse the polarity, as this may instantly damage the ESC.
Thruster Connection (Power Output): Connect the three phase wires of the underwater thruster (usually U/V/W or three identical-colored wires) to the motor output terminals of the ESC. In underwater applications, the phase sequence does not need to be strictly defined. If the rotation direction is found to be incorrect during testing, simply swap any two of the three wires to reverse the motor direction.
Signal Connection (Control Input): Connect the PWM signal wire and ground wire (GND) from the flight controller or receiver to the signal input port of the ESC. Make sure the signal ground and power ground share a common reference to ensure stable control signals. Safety Note: After testing is completed, all exposed terminals must be properly sealed and insulated using waterproof silicone, epoxy resin, or heat shrink tubing.
Before the first operation, the underwater thruster must complete throttle calibration.
This allows the ESC to accurately recognize the controller’s minimum and maximum throttle signal ranges, preventing the thruster from suddenly spinning at high speed after deployment.
Calibration Procedure:
Ensure the thruster is in a safe condition.(You may temporarily disconnect the thruster, or make sure there are no objects nearby.)
Move the throttle stick of the remote controller or main controller to the highest position (100%).
Power on the TW ESC.The ESC will emit a specific tone, indicating that it is recording the maximum throttle position.
Immediately move the throttle stick to the lowest position (0%).The ESC will emit another confirmation tone, indicating that the minimum throttle point has been successfully recorded.
Calibration is complete, and the ESC enters standby mode.
The thruster layout of underwater robots (such as vector configurations or X-shaped layouts) has strict requirements for rotation direction.
Testing Steps:
Slowly increase the throttle and observe the thruster rotation direction or water flow direction.
Compare the result with the system design drawings and confirm whether the thrust direction is correct.
If the direction is reversed:There is no need to modify the software or flight controller settings. Simply disconnect the power and swap any two of the three phase wires between the ESC and thruster to reverse the motor rotation direction.
After completing the steps above, your underwater propulsion system is ready.Watch the video below to see the complete practical demonstration, detailed wiring explanation, and underwater thrust testing.
Q1: The thruster makes a “beeping” alarm sound after powering on but does not rotate. What should I do?
A: This is usually caused by an unrecognized signal or incorrect throttle position.Please check:
Whether the signal cable is securely connected and shares a common ground
Whether the throttle stick is at the absolute minimum position (0%) when powering on
Whether throttle calibration has been completed
Q2: Does the underwater ESC require additional waterproof treatment?
A:The CubeMars TW Series ESC features a highly reliable underwater sealing design, typically using pressure-resistant housings and waterproof connectors.However, any user-modified or extended cable connections must receive additional waterproof sealing treatment (such as potting). This is the most important step to prevent water ingress and short circuits.
Q3: Is it normal for the ESC or motor to become hot after long operation?
A:Underwater equipment relies on surrounding water flow for cooling.If the system is operated at full load in air for a long time, heat generation is normal.
Always ensure that the thruster is fully submerged during actual underwater testing to achieve optimal heat dissipation.
CubeMars is dedicated to providing efficient and reliable propulsion systems for underwater drones, ROVs, and marine exploration equipment worldwide.
[Learn more about CubeMars Underwater TW Series ESC specifications]
