Ultra Low Profile Power Resistors for Electric Vehicles(EV)

Like all other industries, the rapid advancements in design and technology in the electrical & electronics industry is enabling manufacturers to ramp up their product portfolios with products that are lighter, sleek & compact and at the same time delivering robust performance. The initiative and efforts required in designing a completely new line of Ultra Low Profile – Slim Resistor products was in line with this market requirement that is believed to gather momentum over the next couple of years.

In fact, most recently, one of the top Electric Vehicles Manufacturer in India, approached us with a specialised requirement for a power resistor with a very small profile size dimension, to be used in their Electric Vehicles.

The ULS resistor has the distinction of being one of the slimmest power resistors in the market across the world. It comes with a 6mm profile thickness encased in a sleek and sturdy Aluminium body.

The ULS series of Ultra Low-Profile Power resistors was introduced into the market in 2019. Since then the ULS resistors range has found wide application in Electric Mobility, Power Electronics, Automation / Test equipment and Drives, Frequency Converters, Medical Electronics and Industrial Automation.

Product Features:

• Ultra Slim, about 6mm profile thickness
• Resistance range supported : 3.3Ω – 1KΩ
• Best suited in applications where space really matters
• Sturdy and sleek Aluminium body
• Excellent short term overload & continuous power performance
• Excellent Electrical stability, reliability and mechanically very rigid
• CE Marking for export market
• UL approved cables used for terminations
• RoHS compliant product
• Have good environmental protection – IP60
• Customizable terminations upon customer request

ULS Product Variations

ULS 50

• Wire wound resistors with 50W power rating
• 50mm length, 75mm width and 5.7mm thickness

ULS 100

• Wire wound resistors with 100W power rating
• 100mm length, 75mm width and 5.7mm thickness

Industry Application

Ultra Low Profile Resistors for Electric Vehicles

In the Electric Vehicle (EV) industry, High power resistors are used in a variety of applications. Power converters for charging systems, power control units, power distribution units, motor control units and battery modules are the most important uses.

The following circuit diagram shows the original requirement for ULS Power resistors in the pre-charge circuit of Electric Vehicles.

ULS Resistors used for Pre-charge application in Electric Vehicles

A pre-charge resistors slowly charges the capacitors inside an electronic speed controller before it is powered up. Without this resistor, closing the contactor would generate a large amount of inrush current causing the contacts to arc, resulting in a poor connection and diminish vehicle performance.

Pre-charge and Discharge application is used in the Renewable Energy sector too, but with a different circuit diagram.

Applications for ULS wire wound power resistors in the EV and renewable energy industry sectors are listed below:

• Converters in charging systems – Pre-charge and discharge resistors
• Variable speed drive systems – Dynamic Braking resistors
• Engine cooling – Resistors with or without a heat sink
• Renewable Energy – Pre-charge and discharge resistors

TECHNICAL SPECIFICATIONS

Rated Power (W)	50W / 100W
Resistance Range	3.3Ω – 1KΩ
Termination type	Cable lead-out
Application	Discharge, Dynamic Braking, Filter Resistors, Anti – Surge / Pulse Withstanding, High Power
Construction	Wire Wound
Mounting	Chassis/ Heat Sinkable Mount, Screw Mount

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KWK Resistors is a global market leader in resistor solutions with satisfied customers all over the world. High power resistors, Braking resistors, Film Resistors, Wire wounds, Punched Grids, Metal Clad resistors – whatever the type of resistor solutions customers are looking for are available. Solutions can cater to a broad spectrum of resistance requirements – from a fraction of a watt to hundreds of kiloWatts.

With world class Resistors design and manufacturing capabilities in-house, KWK excels in understanding customer’s needs and delivering customized solutions to suit them perfectly. An industry pioneer with over 40 years of experience, KWK resistors is a Joint Venture between the three leading Power Resistor manufacturers – K S Instruments Pvt Ltd India, Krah Group Germany, and Widap Switzerland.