Synchronous or asynchronous motor ?
Asynchronous motor
The term asynchronous comes from the fact that engine speed is not exactly determined by the frequency of the currents flowing through their stator.
The asynchronous motor is the most widely used in the industry for its manufacturing cost, its ease of maintenance, and its good adaptation to speed variation.
However, it has relatively low efficiency.
Synchronous Motor
On these engines, the ratio between engine speed and voltage frequency is constant. With regulated torque, it just draws the current needed to deliver the torque you want at a given rpm. Its efficiency is greatly improved.
Mechanical or electronic switching ?
Mechanical switching : Brush
Simple in design, brushed motors create the necessary alternating field by means of friction contacts. They have the advantage of being inexpensive, but the wearing out of the brush requires regular maintenance. In addition, friction causes a drop in efficiency.
Electronic switching
The alternating field is created by an electronic circuit, frequency converter. These systems are very efficient and do not require maintenance. This high technology is more expensive but is now accessible to the general public.
Electromagnetic or permanent magnet excitation ?
Electromagnetic excitation
The excitation is generated by a coil. Inexpensive, these motors are used for inexpensive applications.
Permanent magnet excitation
The excitation is generated by a coil. Inexpensive, these motors are used for inexpensive applications.
All the motors we offer are synchronous motors with electronic commutation and permanent magnet.
48 V or High voltage ?
The power of a motor is derived from the formula P = UI (voltage multiplied by Intensity)
To increase the power, we can therefore intervene on the 2 factors up to certain limits
The limits of the voltage increase
The regulations prohibit the use of a voltage greater than 50 volts on board a pleasure boat, because of the danger it represents. Motorization is not affected by this regulation. We could therefore consider, as some manufacturers do, increasing the voltage to several hundred volts in order to have greater power. In this case, a qualified and specialized electrician must be called in for the installation and all interventions on board. Make sure that the system is always in perfect condition. This seems possible for a boat that does not navigate much and returns to port every night but is unreasonable for more intensive use when cruising or traveling.
The limits of current increasing
Increasing the current induces an increase in the cross section of the cables as a function of the distance (ohm law). This can generate additional weight and installation difficulties (stiffness of the cables). In addition, beyond 500 amps, it becomes difficult to find affordable electronic components.
48-volt motors are therefore limited to a power of around 15/20 kW. You can obtain more by combining several 10/15/20 KW motors as OCEANVOLT does for the AXC40 but it might be complicated to go further than that.