Recently, many customers have asked us about Bussmann contactors. Now, use this article to solve most of the customer's doubts. The contactor complies with the automotive-grade standard and can be matched with Bussmann's ev fuses for better performance.

The picture below is the combination of Bussmann's fuse and contactor.

Q1: Problems existing in the overcurrent protection in the current high-voltage system of electric vehicles

A:

  In the high-voltage circuit of electric vehicles, the combination of load controller, fuse, and contactor is mainly used for overcurrent protection. When the load controller functions normally, the overcurrent can be turned off by the controller itself, but when the load controller functions abnormally, fails, or has a fault on the line, it is mainly protected by fuses and contactors. Therefore, the reliability and integrity of the "coupling" of the contactor and the fuse are particularly critical and important.

  At present, the common problems are: the contactor itself has a low ability to cut off the overload fault current and cannot cut off the fault current safely; at this time, the general fuse has a long time to fuse the overload fault current, and the system line cannot withstand it, causing The aging of the line fault can not play a truly effective protective role, or because of the use of fuse specifications with imperfect performance, this type of fuse cannot break the overload fault current but cause serious accidents such as arc spraying or explosion.

Q2: What are the product features of the Bussmann EV series fuses?

A:

  Bussmann EV series fuses are developed and designed with reference to the current major "Automotive grade" fuse standards in the electric vehicle industry (GB/T 31465, ISO8820, and JASO D622) and provide comprehensive testing and verification reports; the 500Vdc series provides a full range of 5A~1000A, consistent appearance design; 

  Different from the common ceramic, plastic, epoxy fiber tube body material design, the tube body made of glass fiber mesh material is used; the product has excellent anti-explosion, anti-aging, anti-mechanical stress, anti-vibration and impact resistance performance;

  In addition to the extremely high 20kA (EV10~EV30 series) or 50kA (EV40~EV60 series), which fully meet the limit short-circuit breaking capacity requirements of the current power battery system, the product also has a minimum breaking capacity lower limit of 1.3 times or 2 times; The effective protection range is wide.

Q3:Advantages of the fuse protection characteristics of the Bussmann EV series fuse

A:

  Bussmann EV fuses are not re-validation or "compensation" of fuses for general industrial use; they are newly designed products with "fuse protection characteristics" after fully considering and studying the characteristics of electric vehicles' current operating conditions;

  In the high-voltage circuit of EV electric vehicles, there are usually high and repetitive inrush currents. The system requires that the fuse can withstand well in this area and should not have "malfunction"; once a short circuit occurs in the circuit, a large Current fault requires fast fuse protection; 

  Bussmann EV series 225A as an example, when the peak withstand performance is similar, some fuse solutions tend to be designed for “slow fuse” product design, which leads to the slow fuse speed in the fault high current protection area (such as Competitor A); some fuse solutions actually use a larger size melt design method, so that the protection efficiency of the product in the fault high current area is still low (such as Competitor B). The Bussmann EV fuse is a product that truly takes into account the characteristics of inrush current withstand and fault high current fast fuse protection.

Q4： What are advantages of the Bussmann EVC 500Vdc series DC contactors

A：

  Bussmann EVC 500Vdc series DC contactors not only have the general functional characteristics of ordinary DC contactors, but also in accordance with the requirements of Automative standard the products are subjected to mechanical vibration shock, cold and hot temperature shock, alternating wet and heat cycle, switch-on Current impact life test and other projects have been verified; the contact system and gas arc extinguishing system of the product have been upgraded, and Bussmann EV series fuses are used to achieve full-range current protection: when the maximum current is 8kA, EV fuses can reliably fuse protection, EVC contactor contacts do not weld, with a maximum breaking capacity of 8 times, the EVC contactor can cut off the overload current in a timely and reliable manner.

Q5：Practical significance of "8kA fuse protection against melt welding" of Bussmann EV fuse and EVC contactor combination

A：

  At present, the general situation in the industry can basically only meet the requirements of “6kA fuse protection without fusion welding”. Thanks to the excellent current limiting capability of Bussmann EV fuses and the overcurrent tolerance capability of EVC contactors, we have raised this indicator to 8kA. at a higher level in the industry;

  Fully meet the protection requirements of the contactor Type II under the protection of the SCPD device specified in IEC 60947, which improves the higher reliability and safety of the contactor when a short-circuit fault occurs;

  "8kA fusing protection non-fusion welding" aims to put forward better technical level requirements for the overcurrent resistance level of the contactor contact system. In the current DC contactor product standard, there is no contact resistance, peak value A clear test and verification method is proposed for the current impulse withstand capability, but the welding of contactor contacts is indeed one of the main problems that plague practical applications. Improving and improving the welding resistance performance indicators of contactor contacts is an important solution to this problem. via.

Q6：Bussmann EV fuse and EVC contactor combination

A:

   Bussmann EV series fuses can reliably break any fault current between 2*In (1.35*In) ~ 20kA (50kA); and when the fault current is less than 8kA (measured value), it can also protect the EVC contactor without the contact fusion welding occurs;The Bussmann EVC contactor has the ability to break the fault current at 8*In. When the fault current is less than 6*In, the contactor can complete the reliable breaking under the operation of the control loop;

  When the Bussmann EV fuse and EVC contactor are used in combination, as shown in the figure above, the fuse can reliably break and protect the fault current below 8kA. The contactor controlled by the BMS and the fuse coordinate protection. The fuse can directly break the protection within the set time range, so as to avoid the defect that only the fuse protection delays too long and cannot achieve timely protection.

Q7：What is the application of the Bussmann EV fuse and EVC contactor combination

A:

  Bussmann has rich experience in the application of fuses in EV systems. After selecting the fuse specifications according to Bussmann's consistent selection method, there is no need to select the contactor specifications again, but directly according to the fuse and The contactor's matching table directly selects the contactor specifications that are suitable for the use of the system and at the same time meet the "matching" characteristics of the fuse and the contactor. At the same time, it also saves customers many considerations and costs of repeatedly researching and verifying the matching performance of fuses or contactors. Bussmann provides a "one-stop" solution.

Q8：What is the difference and connection between Eaton Bussmann's existing contactor product range ?

A：

   Eaton Electric Group has a hundred years of technical capabilities and product application experience in the design, development and production of contactors, circuit breakers, switches and vacuum arc extinguishing; these provide strong technical support for the "birth" of EVC DC contactors

  Bussmann has been deeply involved in electric vehicle-related applications for more than 20 years; he is well aware of the characteristics and “pain points” of fuse protection and contactor control applications in electric vehicle high-voltage systems. Take into account and solve the key technical and application problems of overcurrent protection and control and short-term tolerance in line Eaton Bussmann's comprehensive technical support capabilities can provide complete application technical consultation and product solutions no matter when customers select contactor, fuse or "contactor and fuse matching" combination selection; It is better than other fuse or contactor manufacturers.

Q9：Why we choose the reliable Bussmann EVC contactors?

A:

Eaton Group, a subsidiary of Bussmann, has a hundred years of technical experience and history in the design, development, and production of contactors, circuit breakers, switches and vacuum arc extinguishing. Its Moeller and Cutler-hammer are world-renowned brands in this field. As one of the world's largest fuse R&D and manufacturers, Bussmann has in-depth research and application of overcurrent protection and selective coordination in electric vehicles. The existing problems and contradictions, and the development direction of product technology have a deep understanding and rely on strong technical research and development capabilities to develop product solutions with reliable quality and complete functions.

In 2018, Eaton Bussmann cooperated with manufacturers of vehicle-mounted DC contactors in the industry to conduct in-depth cooperation in product design, development and manufacturing to develop and produce EVC series contactors with the above-mentioned advantages. Quality control complies with the quality management system requirements of IATF16949 and the quality and quality requirements of many car manufacturers. Eaton Bussmann EVC contactors meet the standards and test requirements of mainstream electric vehicle contactors and form perfect protection cooperation with Bussmann EV fuses, which can solve many key technical problems of overload protection, short-circuit breaking and short-circuit withstand capability. A complete set of product solutions. The product combination scheme of Bussmann EV fuse and EVC contactor has received warm attention from many vehicle manufacturers and supporting device manufacturers at home and abroad, and has begun to carry out actual testing and verification of the combination scheme products, in anticipation of using this set The new technical products bring more safe and reliable technical performance experience to the vehicle system.