Variable Frequency Drives


Variable frequency drives (VFD), as the name suggests changes the frequency of the motors and thus the speed & consequently, the energy consumed. The savings in energy can be up to 60% of the present consumption of the motors.


The VFD is a device that can control the speeds of motors of pumps and fans on board a ship to meet load demand conditions.


Pumps and fans form most part of the electrical load on board a ship.


They are designed to operate under the most stringent / extreme conditions of load.


The ships however, for most part of their working life never reach these conditions.


In fact, the operation of the vessel at slow and super slow speeds today, further reduces the requirement for high loads.


Also typically, most vessels have almost 50% of the time spent in Port / year where the requirement of high power does not exist at all in Engine Room . This is especially true for blowers and sea water cooling pumps


Control of the vessels motors that drive – (fans, pumps and compressors) to just ch the load requirements, results in enormous savings through reduction of the electrical load and consequently money.


Typical savings for various applications are as follows :


EQUIPMENT SAVING POTENTIAL %
Blowers and fans 30-35%
Feedwater pumps 30-40%
Sea water circulating pumps 30-35%