CRESSALL RESISTORS EV, Marine & Offshore Resistors

A revolutionary resistor designed for low and medium voltage applications, especially severe conditions in automotive, traction or marine systems.

Manufactured from advanced materials the EVT and EV2 have a patented design that encapsulates and totally separates the resistor elements from the water based coolant providing a modular, light weight, low volume, high power solution for water cooled applications.

Typically the EV range are 10% of the volume and 15% of the weight of the equivalent conventional convection cooled DBR. Units can be combined together to handle from 10’s to 100’s of kW and supplied as individual components, frame mounted assemblies for integration in customer’s systems or completely enclosed multi-banked systems that include inlet/outlet manifolds, flow and temperature monitoring.

The latest hybrid/electric vehicle developments mean there is an urgent need for a new approach to regenerative braking. Our EVT resistor with its lower 10kW power rating and reduced pressure drop provides the higher reliability, mechanical simplicity and low weight demanded.

The EVT is the most cost effective way to ensure any excess energy the vehicle produces is safely and efficiently recycled within the car itself. The need for three independent braking systems in hybrid/electric vehicles means that regenerative braking using the EVT is the greenest way for these vehicles to dissipate energy.

Our EV  resistor range provides dynamic braking of all types of low and medium voltage AC drives in:

• Hybrid and all-electric vehicles
• Winches and cranes
• Cable laying vessels
• Propulsion drives on ships or oil rigs
• Dummy loads and discharge resistors for MV electrical systems
• Liquid heating
• Patented design that encapsulates and totally separates the resistor elements from the coolant.

Options for coolant mediums
Water/glycol mix – for operating voltage up to 1.0kV
Demineralised water – voltages to 1.5kV (per series EV module)

Advanced materials & design
Light weight, high power density, GRP (non-metallic) construction

Extensively tested
Proven to meet all major shock and vibration standards for automotive/traction use.

IP56 ingress protection
Suitable for for automotive/traction/marine use.

Low time constant
Full output temperature within 2 sec for heating applications.

FRESH WATER

Most ships have a chilled water system, which circulates cool water throughout the vessel, used for both air conditioning and equipment cooling. It is usually straightforward to incorporate resistors of the type shown into these circuits.

This design of our water cooled resistors range utilises 316 grade stainless steel vessels, cable box and fixings as standard and has the following features:

• Continuous power: 100kW – 1800kW
• Vessel size: 1700–3700mm long
• Vessel bore: 200-500mm dia.
• Voltage rating: 800V DC
• Elements: Mineral insulated with Incoloy sheath, test voltage 2.5kV.
• Operating pressure: 3 bar, test pressure 10 bar. Cable box: IP56 complete with automatic anti-condensation heater and terminals for one capillary thermostat and one PT100 temperature sensor

SEA WATER

Construction and ratings as our fresh water designs but with titanium-sheathed elements in higher-grade stainless steel vessels, suitable for continuous duty in hot sea water.

EVT & EV2 COMPACT, MODULAR RESISTOR

A new range of water cooled resistors for low and medium voltage applications, especially severe conditions in marine systems. Rheostatic braking of all types of low and medium voltage AC drives in:

• Winches and cranes
• Cable laying vessels
• Propulsion drives on ships or oil rigs
• Dummy loads and discharge resistors for MV electrical systems
• Liquid heating
• Patented design that encapsulates and totally separates the resistor elements from the coolant.

RECIRCULATING BRAKING RESISTORS

The closed air/closed water (CACW) system can be used within a braking resistor to limit the braking resistor energy absorbed by the resistor being transmitted into the surrounding machinery room where an increase in ambient temperature could have detrimental heating effects on other installed equipment.

Using CACW can ensure up to 95% of the braking resistor energy is removed from the air and transmitted into the cooling water supply of the ships system over a period of 30 minutes after energy application.

For large vessels, where many Mega Joules are involved, preventing this energy going into the ambient air can limit the air changes per hour required in the machinery room, keeping the room as close to its normal temperature level as possible.

FORCED CONVECTION FAN COOLING

These units are suitable for both protected area and deck mounting and would include anti-vibration mounts to prevent vibration transmission to the floor, with enclosures and all fittings and fan in 316 grade stainless steel:

• Total continuous power: 200kW – 1500kW
• Maximum number of electrically separate sections: 14
• Voltage rating: 800V DC or 690V 3 phase AC
• Elements: Mineral insulated with Alloy 825 sheath, test voltage 2.5kV
• Cable box: IP56 complete with automatic anti-condensation heater and terminals for one termination of capillary thermostat and PT100 temperature sensor for air temperature sensing.

FAN COOLED BRAKE RESISTORS, POWER RATINGS AND DIMENSIONS

NATURAL CONVECTION COOLING

For small inverter drives we can offer our standard ES range, intended for indoor use only within protected areas and would usually be incorporated within or on the roof of the inverter drive system control panels. The standard ES range enclosures are in galvanized sheet steel but for marine and offshore these would be either optionally 304 or 316 grade stainless.

For small inverter drives we can offer our standard ES range, intended for indoor use only within protected areas and would usually be incorporated within or on the roof of the inverter drive system control panels. The standard ES range enclosures are in galvanized sheet steel but for marine and offshore these would be either 304 or 316 grade stainless.

For higher powers and voltages we can design have custom-built designs resistors for on deck mounting, optionally as described below with air-to-water heat exchangers

• Total continuous power: 1kW – 150kW
• Maximum number of electrically separate sections: TBA
• Voltage rating: 800V DC or 690V 3 phase AC
• Elements: Mineral insulated with Alloy 825 sheath, test voltage 2.5kV.
• Cable box: IP56 complete with automatic anti-condensation heater and terminals for termination of capillary thermostats and PT100 temperature sensor for air temperature sensing.

MARINE NERS

A 7.5A 10 second/1.5A continuously rated NER utilising a VT and CT for use within the protection system of a 11kV generator supply, for marine and offshore applications. This design utilises coiled coil resistors mounted between insulation boards.

The surface coating on this design is suitable for marine and offshore environments and is painted stainless steel. Other materials, such as unpainted 304 or 316 stainless steels can easily be used.

MARINE NETS

We also design and manufacture neutral earthing transformers specially for use in the marine and offshore industries.

Cressall Resistors Brochure

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