Aquila has developed en electric propulsion system for Onean Boards. Through the ad-hoc design of every component they have achieved a module which perfectly integrates into the boards. Read more and find out about the main features in this article.
MAGNETIC DRIVE COUPLING
Through the magnetic coupling, the torque produced is transmitted to the exit shaft without contact (mechanical power transmission with no physical connection). This element is essential to guarantee total water tightness in the electric area of the jet unit. On the other hand, it eliminates any existing wearing parts that in other watertight couplings need periodical maintenance.
The coupling is designed in a way that, if any object were to enter the turbine and block it, both shafts would uncouple as a motor protection security mechanism. In order to reestablish the coupling, the motors will need to be stopped.
DUAL BRUSHLESS MOTOR
To provide shaft motion, the jetpack incorporates a double-stator brushless motor. This proprietary design with a non-typical configuration allows to reduce the overall jetpack diameter without sacrificing power.
The commutation is done electronically, improving efficiency and solving the need of maintenance on traditional brushed motors.
Aquila motors are designed to work directly on the range of speeds according to the turbine which avoid any gear that would adjust the turbine speed of the motor with the one from the water pump. Once again, a part that usually requires maintenance is no longer necessary and also reduces losses due to transmission.
COOLING SYSTEM
One of the main challenges is the dissipation of the heat generated in the semiconductors and the motor. Usually water cooling through heat interchanger boards are used. In the case of water jet, it is a fairly easy solution since a high pressure zone already exists in the nozzle, and a faucet could be place on this area. This has serious disadvantages towards the maintenance and also regarding the robustness of the unit. The couplers circulating the water deteriorate over time and clog up due to saline residue or external objects. This could lead to an overheating of the unit causing malfunctioning or even destruction.
The design developed by Aquila favours simplicity and for this reason direct thermal conduction through the steel tube was chosen. Whenever the board is in contact with the water, it is well cooled, even with the motor being turned off.
On the other hand the Jetpack incorporates an internal air circulation system for forced convection cooling. This second cooling system complements the previous one regarding the parts that do not use thermal conduction as a primary way of evacuating the excess heat. Taking into account that it is an internal air recirculation, it does not compromise the water tightness of the unit.
WATERPUMP
The mechanical energy of the motor is transformed into trust using water jet propulsion. The turbine intakes the water through the lower part and ejects it at high speed out the nozzle. To obtain this result, a two-impeller set is used where one spins at very high speed raising pressure and the other one redirecting the fluid.
The blades of the impeller could be damaged by an external object or by repeated use. For this reason Aquila Boards designed an easy to replace impeller, stator and nozzle. All material are suitable for marine environments and durable even in saline conditions.
POWER ELECTRONICS
These electronic boards support all the electrical power during the motor commutations. (…)
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