As standard, asynchronous, 3-phase, squirrel cage motors are applied for the driving of tunnel thrusters in marine execution, certified by the marine classification society.
The following parameters, among others, are designed to the Customer's requirements: voltage (low , medium), frequency, duty class, protection degree, insulation class. The motor windings are equipped with temperature sensors and anti-condensation heaters.
Other configurations of a thruster’s drive are also possible including hydraulic motor or diesel engine.
Drive system for CPT
The standard drive system of a CPT thruster consists of:
electric asynchronous, squirrel cage motor
compact starting autotransformer which limits the starting current
control system, placed in control box (together with propeller pitch control system)
The compact starting autotransformer is designed according to the characteristic’s of an electric motor.
Two power switch-disconnectors for the proceeding of the motor start up process (vacuum contactors for middle voltage motors) are built-in inside the starting autotransformer instead of starting the switchboard. Thanks to that, connections to the power switch-disconnectors are very short and external power cable connections are avoided.
The autotransformer enables limiting the starting current to 1,5 (on request even to 1,1) of the motor nominal current.
Alternatively the drive system of a CPT thruster can consists of:
electric asynchronous, squirrel cage motor;
soft-starter;
control system, placed in control box (common with propeller pitch control system).
The soft-starter enables limiting the current to a level of 2,2 of the motor nominal current. The soft-starter is built into the control cabinet (together with the remote control system).
The electric motor and compact starting autotransformer or soft-starter are certified by the marine classification society.
Drive system for FPT
The standard drive system of a FPT thruster consists of:
electric asynchronous, squirrel cage motor
frequency converter
remote control system, placed in bridge console insert
The electric motor is designed for usage with a frequency converter (insulated bearing and strengthened winding insulation). The frequency converter is defined according to the characteristic’s of an electric motor. The frequency converter controls the motor start-up as well as the motor rotation speed and direction.
The electric motor and frequency converter are certified by the marine classification society.
