Unmanned Underwater Technology
full ocean depth pressure-tolerant motor controllers pressure-tolerant brushless DC motor controllers
UUdrive 11,000m depth-rated motor controller

UUdrive is the only 11,000m depth-rated, pressure-tolerant motor controller of its class: a compact and light-weight, three-phase variable frequency drive for permanent magnet motors.

In addition to obvious buoyancy advantages, zero implosion risk, and elimination of high-pressure seals, installing a pressure-tolerant motor controller inside the motor housing has maintenance and fault-tolerance benefits over traditional in-air solutions. The controller and motor assembly can be tested and serviced as a unit, and external cabling and connectors for the high-current motor windings, position, and temperature sensors are eliminated.

Building on the success of its predecessor, which was used to drive all thrusters and hydrualic pumps on James Cameron's Deepsea Challenger submersible, this second-generation design supports higher DC bus voltages and offers additional control and feedback options. The same design has also been demonstrated in rotary actuators, suction samplers, and other applications.

The unique ring heat sink arrangement is ideally suited for a sliding fit inside an aluminium motor housing, though other mounting arrangements are possible. Exposed components are compatible with most mineral oils, silicone fluids, and fluorinated liquids. Thermal expansion during operation ensures good heat conduction through the housing to seawater.

Micro-scale pressure-tolerant motor
drives for miniature ROV/AUV thrusters

Ready-to-run evaluation systems including a UUdrive controller, example motor, precharge switch, USB PC interface, and control software are available now. We are also in the process of making complete thrusters based on this technology available through our integration partners. Contact Unmanned Underwater Technology for more information, or to discuss your application schedule.


Controller power10kVA continuous (subject to cooling)
Controller efficiency> 98% for typical operating modes
Motor suitabilityThree-phase permanent magnet
motor w/ rotor position sensors
(sensorless option available)
Maximum DC bus voltage100V (200V option available)
Maximum motor current100A RMS
Communications interfaceRS-485 (Modbus protocol)
CANbus (CANopen protocol)
Control and feedbackMotor speed and current
Controller temperature
Depth ratingDesign depth 11,000m (~110MPa)
Test pressure 120MPa (~12,000m)
Physical dimensions88.9mm (3.5") diameter
50.8mm (2.0") height
Weight300g in air
170g in water

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