FIRSTOHM Anti-Surge Wire Wound Resistors Possessing Multiple-country Welding Point Patents, Enhance Product Reliability, Offer High Pulse Withstand Capability

时间： 2024-11-09 来源：Firstohm Official Website

技术问答

Pre Charge Resistor

Pre-charge circuit is a circuit design principle where specific components (such as capacitors) are pre-charged before the electronic device is powered on and then connected to the main circuit. The purpose of this is to reduce the current impact during startup, protecting the system and components from excessive voltage or current effects.

This pre-charge principle effectively reduces the impact during the startup of electronic devices, prolongs the lifespan of system components, and enhances the overall stability of the system.

Welding point patents of FIRSTOHM Wire Wound MELF Resistors:

1. Taiwan patent number: M530462

2. Japan patent number: 3208923

3. China patent number: ZL201490001291.X

4. Korean patent number: 20-0486309

5. United States patent number: US9978483B2

Application

• Industrial Power Supplies

• Inverters

• Battery Management Systems

• Electric Vehicle Charging Stations

• Energy Storage Systems

• Industrial Equipment

General Specification

FIRSTOHM Anti-Surge Wire Wound Resistors (SWM/SWA): Possessing multiple-country welding point patents, these resistors enhance product reliability, offer high pulse withstand capability, are cost-effective, and come in a compact size. They are particularly suitable for use in pre-charge resistors or discharge resistors.

※ Type of pre-charge resistor

※Reference Case: Pre-charge Circuit for Inverters

FIRSTOHM P/N : SWA03J68R0TKZTB500(3W 68R 5%) *1PCS

Test Conditions: Input Voltage: 357.8VDC，Charge Capacitance: 648μF，Number of Test Cycles: 10,000 cycles

Test Result: △R:+0.42% (PASS)

Maximum Power = 357.8V x 357.8V/68R = 1882W, Time Constant (RC/2) = 22ms (In pre-charge applications, the time constant when energy is at its maximum depends on the values of the RC (resistor and capacitor) components in the circuit. The time constant (τ) is typically calculated as half of the product of RC. Time Constant (τ) = RC / 2.")

SWA03 can withstand 3,000W under 22ms. (refer to the SWA03 surge performance chart below.)

※ Firstohm-The specifications of Anti-Surge Wire Wound MELF Resistors (SMD) are as follows:

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