Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [inrush-current]

The high current, that often occurs when first plugging an appliance in the power supply.

Inrush current, input surge current or switch-on surge refers to the maximum, instantaneous input current drawn by an electrical device when first turned on. This commonly occurs in cold incandescent light bulbs, alternating current electrical motors, transformers. The results could be blown fuses, tripped circuit breakers, overcurrent situations.

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P-Channel MOSFET Inrush Current Limiting

I have been searching EESE and Google for several weeks now for a solution to this problem, and while I found some proposals that seemed promising, the real-world implementation fell short of expectations. I have a voltage regulator on a board with…
DerStrom8
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Capacitor Inrush Current

I have to filter a power control circuit and as usual I am using lots of capacitors in parallel. Some of these capacitors are Tantalum or Aluminium Polymer types, with ripple current ratings of 3 amps or so... in normal operation the ripple current…
mFeinstein
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P-Channel MOSFET Inrush Current Limiting - Transistor burn issue

I'm fighting with PFET inrush current limiting circuit discussed here: P-Channel MOSFET Inrush Current Limiting In my circuit is input voltage 24V DC and C_Load is 6mF. I'm switching on transistor slowly 150 ms => and that limit current quite well…
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Choosing inductor to limit inrush current

I have a 12V DC input to a circuit. There is a 660uF Aluminum cap on the input. The 12 volt source is not in my control and can come from anywhere. So it could be a noisy source or a high current clean source. I am wondering if it's worth it to put…
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How to find the root cause of this relay failure

The following is the schematic for the relay section of the board: VBAT: 45-56 V. RY_REAR_MOT: Power to the front motor controller RY_REAR_MOT_EN: 3.3 V enable signal from the MCU. On power up, this remains low. After a 30 s delay, this signal is…
Hasman404
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Energy efficient inrush current limiting

Short version: looking for simple and energy efficient way to limit capacitive inrush current. Primary design goals are to minimize radiated heat and current draw during normal operation. The schematics must allow intermittent operational current up…
Maple
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Are inrush thermistors thermally insulated?

Vaguely related to this question but with some different questions and a different component. For an inrush-limiting NTC thermistor such as the Ametherm SL series: It seems purposefully designed to run hot when at the steady-state current, and this…
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DC Relay overrated for max. 100ms

In my case I need a relay to switch continous 0.5A at 24V DC, but in time of closing the contacts there will occour an inrush current from the further circuit of 6A, but only for max. 100ms because there is a contactor (DC) in line of the switch. I…
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When/where to open and close a transformers output

I came across Beware of Zero-Crossover Switching of Transformers (TE Connectivity App Note) where they discuss about how you shouldn't switch a transformer at the zero crossing because it would have the highest inrush. However, if I am looking to…
efox29
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Question about the Inrush Current in LDO

I have a doubt with inrush current limiting for an LDO. To understand that, I referred old literature of capacitors and others. I have some conflicting arguments which I need to clear out: This is from Wikipedia: The current into a capacitor is…
user19579
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Limiting the inrush current

I have a transformer with several secondaries, and this is how I'm planing to control the inrush current: simulate this circuit – Schematic created using CircuitLab I'm using a resistor to limit the inrush current and MCU will energize the relays…
ElectronSurf
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Can I use a resistor before a bridge rectifier to lower inrush current?

I have been looking for ways to limit inrush current in a power supply circuit I am designing. In LTspice, with no current limiting, I see a spike of around 24A before my caps are charged. Looking around, I see NTC inrush current limiters as a…
samoz
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Filtering Capacitors before the fuse or after the fuse while limiting inrush current?

There are basically two questions I have for this circuit. 1) Which capacitor configuration is good? before fuse or after fuse 2) How do I limit my inrush current? My thoughts: I am confused between weather to put filtering capacitor before the…
dr3patel
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How do I select a replacement ICL NTC thermistor for a PSU?

I want to replace an ICL (inrush current limiting) NTC thermistor in a vintage computer PSU (for Amiga 1200). This question is similar to 'Selecting an NTC for inrush current limiting', except that question was related to a triac control circuit and…
Nick Bolton
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Will this method theoretically reduce inrush current during relay turn on?

When a relay is connected to a purely capacitive load and an AC supply voltage is turned on, it will experience inrush current. Since the potential difference of an AC voltage can be represented by $$V_0sin(\omega*t)$$ then I wonder if the relay is…
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