Category: NEWS

POWER RESISTOR ENCLOSURES:
SEEKING THE ANSWERS

Cressall, has released an informative infographic explaining the essential questions to ask when designing an enclosure.

The guide aims to support design engineers as well as resistor end users across all industries to understand the requirements of their power resistor enclosure.

The infographic is now available to download here.

Power resistor enclosures provide a number of functions, including protection from harsh weather conditions, cooling and preserving the safety of the public. Each of these specifications will vary, dependant on the exact requirements of the client, and the resistor they purchase, however a full understanding is crucial to the design phase.

The research stage is usually undertaken when thecustomer provides an initial specification, but on some occasions, this does not happen, therefore it is the manufacturers responsibility to ask those important questions.

The infographic explains five questions that must be answered in order to design and manufacture an effective enclosure that meets all the required specifications. These queries cover the final resistor environment, industry challenges, aesthetic considerations, health and safety and choices around shipping and installation. By thinking about these points early, the final product can be designed to meet each and every requirement.

“We produced this infographic to provide design engineers, as well as the end user, a checklist of things to consider when they are planning their resistor and corresponding enclosure,” said Andrew Keith, engineering director at Cressall Resistors.

“Sometimes enclosures can be left as an afterthought, but this will rarely achieve the most efficient, advantageous solution. Thinking about the enclosure at the same time as designing the resistor is crucial to ensuring the final product will meet all the requirements, reducing the risk of compromises having to be made.”

Cressall works with clients worldwide to design and manufacture a range of resistors alongside enclosures, including dynamic braking resistors (DBRs), neutral earthing resistors (NERs) and harmonic filters. The full range includes specialised resistors for a number of sectors including rail traction, renewables, marine and offshore.

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CONSUMER RELUCTANCE AND ELECTRIC VEHICLE UPTAKE

Cressall has produced an infographic that explains the reasons why consumers are sceptical about electric vehicles, and how the industry should respond to this reluctance. By supporting design engineers to increase their understanding of consumer concerns, Cressall hopes the industry will be able to overcome many of the challenges it faces.

The infographic is available to download now.

Electric vehicle manufacturers are faced with a range of challenges, including the requirement for more advanced battery technologies. In addition to technical demands, consumer uncertainty is also hindering sales.

The concerns cited by consumers include a short driving range, limited heating and air conditioning and a lack of charging points. Each of these can be improved or overcome by careful design engineering.

For example, driving range can be increased by using regenerative braking to recapture energy that would ordinarily be lost through friction braking.

“By having an acute awareness of the concerns that are making consumers reluctant to buy an electric vehicle, design engineers can ensure their vehicles are more marketable and saleable,” explained Simone Bruckner, Managing Director at Cressall.

“Increasing electric vehicle sales will not only be profitable for manufacturers but will also have beneficial effects on the environment. According to The Guardian, a hybrid vehicle that uses regenerative braking produces 42g less CO2 per km than the equivalent petrol vehicle.

“In addition, electric vehicles are much more efficient and with government incentives such as bursaries, they can be a more cost-effective option for many consumers.”

Cressall’s EV2 advanced modular water-cooled resistor is specifically designed for hybrid and all-electric vehicles. It’s an essential component in the regenerative braking process, discharging any excess energy in case of the battery being full, an electrical fault or an emergency situation.

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AUTOMOTIVE INNOVATIONS WITH EVT WATER-COOLED RESISTORS

Cressall Resistors has announced the launch of the EVT, a new advanced water-cooled modular resistor. Building upon the success of the EV2, which is used for low and medium voltage applications, the EVT has been developed specifically for rheostatic braking for smaller vehicles.

With the same outline dimensions as the EV2, the EVT has a substantially lower power rating of 10 kilowatts (kW). The new unit has a reduced pressure drop, allowing it to better tackle the automotive market. While the EV2 was designed to fit larger vehicles such as trucks and buses, as well as in marine applications, the EVT is intended to fit into more cars.

In hybrid and pure electric vehicles, energy is usually discharged during braking on batteries. This is not always effective as batteries could be full and, moreover, it may not be viable in instances where drivers need to emergency brake. A resistor is the most size and cost-effective brake that can be added into a vehicle, and will ensure that any dissipated energy is safely and efficiently redirected.

Cooling in the EVT is achieved by pumping cold water into one end of the system. The water then absorbs the heat which is pumped out through a radiator.

“Electric braking via an EVT system provides a number of benefits over mechanical braking, including increased control, higher reliability, mechanical simplicity and weight saving,” explains Simone Bruckner, managing director of Cressall Resistors. “Additionally, any excess energy can be used to support the vehicle’s cabin heating, helping to increase overall energy efficiency.

“Air cooling is not efficient in automotive applications. With electric and hybrid car sales reaching a record high in September 2018, this trend is set to continue, meaning a more efficient way to dissipate low amounts of energy is important.”

According to regulations, vehicles must have three independent braking systems for safety reasons. In a conventional car, these are dual-circuit hydraulic brakes plus a handbrake. For electric vehicles, if braking systems aren’t regenerative, the supposedly green vehicles will waste a lot of energy.

The introduction of the EVT means that a wider range of vehicles will benefit from the energy-saving properties of the original EV2. As the number of electric cars on the roads continues to rise, using a water-cooled modular resistor can help vehicles remain as green as their intentions.

For more information on how resistor technology can help advance hybrid and electric vehicle systems, get in touch with Cressall Resistors on 01162 733 633.

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ELECTRIFYING VEHICLE TECHNOLOGIES

Despite appearing to be a modern phenomenon, the first electric vehicle took to the road in 1832 and in 1899, outselling all other available options, including steam and gasoline powered vehicles. Since 1935, with the invention of the internal combustion engines, gasoline-powered vehicles have become the popular choice. This changed in 2016, which saw a record in the sale of electric vehicles worldwide, with 750,000 cars sold.

Here, Simone Bruckner, director at Cressall, explains the recent popularity of electric vehicles and the challenges they have yet to overcome.

In January, car manufacturer Ford announced that it will boost its investment in electric vehicles to £8bn in the next five years, doubling its previous commitment. This investment has been reciprocated by General Motors, Toyota and Volkswagen which have made similar pledges as both consumer confidence and sales build in electric vehicles.

Misconceptions

Through consumer education, many misconceptions that have traditionally prevented the purchase of electric vehicles have now been disproven.

Consumers previously experienced three major obstacles according to a National Renewable Energy Laboratory (NREL) report published in 2016. First is the perceived prohibitive cost, which is rapidly falling as technology advances and can be partially offset by government bursaries and schemes.

Similarly, many drivers worry about a lack of charging points, but this is becoming less of a concern as Poppy Welch, head of the Go Ultra Low scheme explains. “Since the introduction of government’s plug-in car grant in 2011, registrations of electric cars have grown dramatically from 1,089, to last year’s volume of 36,673.” In Europe, there are now nearly as many charging points as there are gas stations.

The last major concern is range. The LMC report revealed that vehicles would need to travel 300 miles on a single charge for the majority of recipients to consider a purchase, which is close to being achieved due to improvements in battery technology.

Regenerative braking

Complementary to research into alternative battery technologies including cobalt, range can be extended by retaining energy lost through braking.

Traditional friction brakes convert the kinetic energy from the car’s motion to heat, where it is lost. However, regenerative brakes have the ability to recapture this energy.

When the motors that power the wheels of an electric vehicle are run in reverse following depression of the brake pedal, they become generators, producing energy that can then be stored in the battery keeping it partially charged, contributing to improved battery health.

Energy capture

Despite the many benefits of regenerative braking, it could present problems when the battery is fully charged or due to an electrical fault. Cressall’s water-cooled EV2 resistor can discharge excess energy captured through regenerative braking in these situations.

The EV2 can also provide cabin heating, of particular importance during winter or in colder countries. Instead of using dedicated resistance only for heating, which is an additional component and draws a lot of current from the battery, the EV2 resistor can allow the transfer of heat into the cabin through cooling or heating water in much the same way as in internal combustion cars.

Regenerative braking may be able to capture half of the 80 per cent of energy lost through traditional friction braking and put it back to work by heating the cabin.

Electric vehicle technology is continually developing through improvements in battery technology, regenerative braking and charging stations and this is only set to continue in order to meet the increased demand for electric vehicles. Although electric cars became unpopular after 1900, there is little doubt that 2018 will more than make up for it.

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