Shore Power Converters

 

Connecting the yacht electrical system to the large variety of marina power supply configurations is a complex task. Nominal voltages of 208, 240, 400 and 460 Volts are common. The frequency may be 50 or 60 Hertz. The supply may be single or three phase. Also more than one shore cord may be necessary to get the required power on board from the outlets available on the dock.

Vectek shore power converters solve these problems while providing benefits not found in other brands. This is because the Vectek VSP series of shore power converters incorporate not only an output converter, but also a separate input converter for each cord-input.  The input conversion process provides the following advantages:

• Maximum power from the dock
The current waveform drawn from the shore power supply is sinusoidal and at unity power factor. This minimizes distortion to the power supply, but more importantly, maximizes the power available from each cord-input.

• Independent cord inputs
Another advantage of the Vectek input conversion process lies in the fact that two or more input converters can be connected to the output converter. In multiple cord-input systems each cord can be connected to a different supply with no need to worry about the voltage, frequency, phase rotation, or even if it is single or three phase. A microprocessor based controller for each input converter takes care of the conversion process independently of the other inputs. They then combine to extract the maximum power available from each shore connection. Should a shore cord become unplugged its pins will be instantly isolated and safe. Each shore cord input has three phase connections, any two of which can be used for single-phase operation.

• Multiple shore cord isolation
Another benefit is that cord inputs have galvanic isolation from each other as well as the output to the ship. This stops any nuisance tripping of the earth leakage (ground fault) protection circuit breakers on the dock. This can occur in systems where the input cords are paralleled using contactors, which allow current to pass from one cord to the other.
The standard input cord ratings produced by Vectek are 50, 100 and 150 Amps (18, 36 and 54 kVA on a 208 V three-phase supply).
The standard range of output converters is 36, 54, 80, 108 and 120 kVA. For custom designs this can easily be extended up to 500 kVA using existing Vectek converter technology.

• Bow Thruster Controller Option
By including some simple contactor switching where the unit is connected to the ship bus, the output converter can be used to control an electric bow thruster motor. The bow thruster option provides speed variation in either direction.

• Output Synchronizing
The synchronizing system to provide seem-less transfer to and from shore power is standard on all Vectek shore power systems.
Many of the shore power systems Vectek have supplied to date have been in modular format. Transformers and converter modules can be supplied separately and wired together on the boat, making better use of available space. This also makes it easier to get on board in the case of retrofits.
New Lightweight VSPII
With Vectek’s new VSP II series of shore power converters, modular design has become standard. Each input module supports one cord up to 50 Amps and is capable of transferring 12 kVA to the output module. A typical configuration would be two input modules coupled to one output module rated at 24 kVA. While this system works well with three phase input it is capable of getting full capacity of 12 kVA from a 240 V, 50 A single-phase marina outlet (or 24 kVA from two).
The VSP II modular system incorporates a lightweight isolating transformer in each input module for galvanic isolation. These lighter units are designed to connect medium sized vessels to the shore supply anywhere in the world. Simply plug it in and it will work automatically

Typical Applications

135 foot Motoryacht Sovereign Lady
Launched by Sovereign Yachts in February 2003, Sovereign Lady is fitted with a VSP3/210-80. The shore power converter had been commissioned two months earlier. This allowed the USA electrical equipment on board to be tested prior to launching using the New Zealand power supply.

33 meter Wave Piercing Catamaran
Two VSP3/115-52’s are fitted, one in each hull of New Zealand Yachts 33 m Wave Piercer. This was done to help preserve the balance of the boat. The outputs from the two converters are connected together using the synchronizing function, which is standard on all Vectek VSP converters.  The two VSP3/115-54 units were custom built to fit into the space available. The converter systems and the transformers were housed separately. Each unit has one 150 Amp cord input and can supply up to 54 kVA on board giving a total of 108 kVA.

Sensation Yachts 50 m Motor Launch
Vectek Marine has supplied a VSP3/215-108 for a 50 meter motor launch, SY24, being built by Sensation Yachts. The shore power system has the Bow Thruster option fitted.  The shore power unit is designed to run off one or two shore cords rated at 150 Amps. This unit provides full galvanic isolation as per ABS requirements, and incorporates Vectek’s “Unity Power Factor” input converter to obtain the maximum power available from each cord shore supply. The 108 kVA output stage is filtered to give pure sinewave power to the ship bus. SY24 is being fitted with a 75 kW electric bow thruster. The inverter of the shore power output stage is switched to provide full variable speed control of the bow thruster motor in both directions.

37 meter Dubois Sloop
The Dubois designed 37m aluminum fast cruising yacht, Midnight, constructed at Fitzroy Yachts, New Plymouth yard is fitted with a Vectek VSP3/115-54 shore power unit. To accept either single or three phase shore power at anywhere from 180Vac to 540Vac and 47-64Hz, it will provide the yacht with a clean steady supply of 400Vac three phase and 230Vac single phase at 50Hz. The unit will supply up to 54 kVA from a single cord input up to 150 Amps.