Questions tagged [inrush-current]

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

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24-60V Precharge schematic critique

I'm looking to design a soft-start precharge circuit for starting up circuits with substantial input capacitance (~1.5J @ 24V). The main requirements are: 24-60V compatible Constant current pre-...
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27 views

Switching Power Supply - Type of MCB for Inrush Current

it's regarding this PSU from Mean Well: https://www.meanwell.com/Upload/PDF/LRS-350/LRS-350-SPEC.PDF It has a 60A inrush current. My lighting circuit (1.5mm2 wiring) is tied to this PSU supplying ...
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34 views

Switching Power Supply - Inrush Current, Input Current, MCB

I am getting several PSUs (LRS-350-24) from Mean Well. Here's the specs: https://www.meanwell.com/Upload/PDF/LRS-350/LRS-350-SPEC.PDF 1) The input current is stated to be 3.4A/230VAC at 88%. 350W ...
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35 views

How to choose a DC-DC Converter for a motor with inrush current? (Theory)

I am wondering how to choose a DC-DC converter for a motor. This is a theoretical question for understanding. For example, if I have a converter that can output 5V with a maximum current of 1A. ...
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74 views

Cheap alternative to limit inrush current (eg. relay bypassing a fixed resistor or MOSFET)

I'm editing the question because several (great) answers focus on the fact that the LTC3780 module (inside ajustable my power supply) can handle the inrush current (maybe, maybe not). I'm glad to know,...
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77 views

Inrush Current problem?

I have a 360W 36V Switch Mode PSU which I am using in a garden lighting system I have designed. I'm in the UK so it's running off 240V therefore can supply about 10A. Each section of the ...
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1answer
50 views

Choosing inrush current limiting resistor for a mains rectifier

I am having a trouble with a mains rectifier. Simplified schematic: simulate this circuit – Schematic created using CircuitLab Only problem I have is that R1 sometime explodes during circuit ...
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76 views

AC “chopping” power supply inrush current problem

I've made a simple AC to DC chopping/switching power supply circuit (I'm not sure if it's called that) as shown below. in the left part of circuit (which is the gating/chopping part) when the ...
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1answer
94 views

LTM8073 integrated DC-DC buck converter issues

I have a board with two LTM8073 "silent switcher µModule regulators" by Analog Devices/Linear Technology being used to provide two separate power supplies. This is a 10-layer dual-sided board that was ...
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3answers
92 views

Chop Saw Inrush Current Limiter?

I have a Dewalt Metal cutting abrasive saw that tends to open a breaker on starting up. It draws 75A on startup tripping the magnetic part of the breaker and opening it. This circuit is only to stop ...
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1answer
115 views

5V Switching Regulator Problems

I have a circuit with two supplies. A 19v supply for stepper motors, and a 5v supply for driving the ATMEGA644, 3 stepper motor driver daughter boards, a bluetooth LE daughter board, and 2 ws2812b rgb ...
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130 views

Surge Current on PCB

When designing a PCB, do you need to worry about the inrush/surge current or just the continuous/RMS current on the board? Everything I have seen including IPC documentation is for continuous current....
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251 views

Microwave oven: How can I temporarily limit the startup load?

Problem: It's a common problem for "NON-inverter" type microwave ovens to pop circuit breakers, and mine is no exception. There could be a huge number of reasons for this. Even though I thought I ...
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1answer
56 views

How to reduce inrush current for DC Motor in boom barrier gate application?

I'm using 24V 25W 100RPM DC geared motor for boom barrier gate application.So I added an overload protection for that circuit but whenever the motor starts the inrush current is produced and it ...
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50 views

Mosfet based inrush current limiter review

Please find below the schematic of a mosfet based inrush current limiter. It works in simulation (Tina TI) but I would like to get your opinion. Do you think the schematic below is a good approach to ...
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220 views

Limiting inrush current in N Channel MOSFET power switch

I have a N-MOSFET as power switch like this: I want to add a fuse on the power line but I have few capacitors on the across the load and I am worried that the inrush current might blow the fuse off....
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62 views

Inrush current limiter circuit for filament bulb - comparison

Context: A 12V power supply is switching on externally connected 12V filament bulbs. The power supply's load switch implements an electronic resetable fuse (13A/τ=15ms) in case of an external short. ...
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1answer
70 views

Inrush current into capacitor bank

Given I am charging a 50uF film cap bank to 500V. Do I need a current limiting resistor or some sort of current regulator to minimize inrush current when i first turn on the power supply and/or limit ...
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3answers
84 views

Apart from speed, do VSD's also alter current?

As I know it, a VSD alters the frequency to change the speed of a motor. I also understand that since the back emf of the rotor is directly proportional to the speed of the rotor, the slower the motor ...
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1answer
59 views

Decreasing the surge power of the AC loads

I have a pure sine wave inverter 12v to 220v AC, its continues output power is 600VA and the surge power is 1130VA, I want to running my 200W fridge, but unfortunately my fridge surge power is a bit ...
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66 views

Reducing surge current in 5V High Side Switch

Re-visiting a prior question I asked a while back. I have a circuit that looks like the following: simulate this circuit – Schematic created using CircuitLab ... and from what I surmised from ...
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1answer
537 views

MOSFET as inrush current limiter (passthrough parasitic C?)

I have a circuit based on a P-FET which shall limit inrush current (20 mA). However, when turning on the power supply there is always a current peak (30 mA, 5 ms) through the M1. Even if I tie its ...
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1answer
1k views

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 ...
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165 views

How to prevent large inrush current without a reset-fuse

In another question (DC-DC booster fails with lead-acid battery source) I described a problem with a DC-DC booster that destroyed itself by dragging a large current when its output was disconnected. ...
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100 views

How to limit starting current of a SEPIC based LED driver?

I have designed a SEPIC based LED driver which gives 60 V, 350 mA constant output with a good power factor. It is connected with 220 V AC source.Then I have used full-wave rectifier.After ...
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3answers
216 views

Does Thyristor (SCR ) works for Inrush current protection?

Does a SCR ie Thyristor work for Inrush current protection in a circuit ?
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161 views

Contactor/relay rating for bypass function of soft start circuit

I am designing a soft start circuit for a 70KVA, 70A, 480/230 delta/star transformer, since the fuses kept blowing without. I've been using 3 NTC thermistors rated for 80A in series with the lines ...
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610 views

How does the high inrush relay handle the inrush current?

I was searching through the high power relays(16A, 240AC) and found that some manufacturers have high inrush capability relays and that too upto 100A inrush current. Below are some examples (one is ...
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2answers
135 views

Limiting Inrush on AC/DC converter

I created a simple power supply as shown below that results in an unregulated 50VDC which is what I desire. The transformer is rated for 1000VA. It works ... but only if you're lucky enough to turn it ...
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68 views

Capacitor for handling startup current of DC-DC converter shows different behavior

I’m using a 5V DC-DC converter to step-up a coin cell (Nominal Voltage: 3V) to 5V which did not work. I suspected that the high startup current of the converter was causing the Cell voltage to drop, ...
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242 views

Surprising Inrush Current on a MOSFET Switch?

I have the following P-ch MOSFET switch used to supply a 12V, 6-20A load: When I enabled the switch, I measured the following voltage drops across +12VDC & +12VDC_GR. The yellow line is +12VDC (...
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1answer
76 views

inconsistent inrushmeasurment depending on “power plug”

I'm measuring inrush current with a current probe ( tektronix P6303) that is connected with an amplifier between, which is powered by an AC line before it's connected to an oscilloscope. I got some ...
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1answer
371 views

Pc power supply Ac in rush current overloading inverter

I have a PC consuming 400 watts hooked up to a 220 VAC automatic backup 1500VA 12V dc inverter since AC grid line is not 24/7 in my country. The main problem is that sometimes when the AC power goes ...
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207 views

Inrush current switch with thyristor?

Background: I've a problem where I need to measure the inrush current of some parallel DC/DC converters in a system where the input voltage may vary between 360-600Vdc on start up. The inrush current ...
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4answers
470 views

Handling transformer inrush current where load varies greatly and is often switched on and off

WHAT AND WHY: I've finally built a isolated supply with a current limiting bulb for my bench. The transformer is a Triad Magnetics VPT230-4350 torrid, 8.5 amps max on the output, 1:1 ratio (home page, ...
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366 views

Inductor Inrush Current Rating

I am experimenting with the simple circuit shown below and was wondering how to ensure that the inductor used would handle the inrush current. My reasoned solution is the following: I solved for ...
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2answers
1k views

Comparing rated, stall, and inrush current in DC motor

I see the definitions of them are: Rated current: maximum current the motor draws (or some says the maximum current the motor can endure?) Stall current: the current the motor draws when hold ...
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295 views

Soft-Start Circuit with Premature Loading

BACKGROUND I am designing a board to convert high voltage (~400V) DC down to medium voltage (~30V) DC to provide power to subsequent boards. In its simplest form, my board will consist of the DC/DC ...
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192 views

Mosfet amp spike in SPICE when connecting power

When powering this circuit I get a 150 microsecond rush of current at 120 amps. Is this a real issue with mosfets? Additional info: I've been playing with N and P channel slow start mosfet circuits ...
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87 views

Mains switch arc - multiple smpsu inrush current

I am working on a design that consists of a mains power entry module which is a filtered, fused mains switch. This switches the live and neutral conductors to feed 4 switch mode power supplies. Each ...
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1answer
2k views

Starting (inrush) current of a resistor (heater)

We are going to purchase a 48kW electric drying oven. As we know the AC motors have big starting current and a special starting equipment is needed - Star-delta, soft-starter, inverter and etc. What ...
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2answers
708 views

Why is Inrush current important to me when buying a power supply?

I am in the process of buying some power supplies and was looking over the datasheet at saw the inrush current is stated as "Coldstart 80A/230VAC" I can also see that the AC Input is rated 1.1A/...
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3answers
553 views

Control inrush current

A basic question, how does the P-Mosfet reduce the inrush current. simulate this circuit – Schematic created using CircuitLab Old image link Can the P-Mosfet's drain and source orientation be ...
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1answer
357 views

Limit inrush current

I'm looking into a LED driver and i'm quite curious about the inrush current. Where does it originate from? Is it to load up the input/output capacitors? Can I limit the inrush current? Whats the ...
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1answer
1k views

Inrush current for LED strip circuit

I am building circuit to control some LED strips. I will be using APA102 strips. https://cdn-shop.adafruit.com/datasheets/APA102.pdf I am using an Arduino to control the strips. The strips will ...
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117 views

Energy storage for AC inrush currents

In DC circuits, if I have a device that gets switched on and has a large inrush current, I can just put a large charged capacitor near the power switch (parallel to the device) to source the surge. ...
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69 views

Design and Protect Device Circuitry from Inrush Current

I am designing a device that will be placed between a 220VAC 50Hz power source and a 1100W 7.7A motor load. The device switches power to the load given a relay input and the motor load draws a ~20A ...
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207 views

In-rush current limit MOSFET, resistor

I'm using DC/DC converter LTC3112 to supply GSM module. Battery source is about 12V and DC/DC output is 3.7V. Microcontroller logic is 3.3V powered from other DC/DC converter. The application is ...
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531 views

How to Reduce Current in Solenoid Coil

First time poster and electrical newbie here. First off I just want to thank everyone for helping create such a great and helpful forum! I've been lurking for years and have learned a lot here! I ...
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2answers
923 views

Spark when connecting battery module to DC power supply

I am using a 60v DC power supply to charge a 48v battery module. I set current and voltage limits first, turn off the DC power supply, connect positive to battery's positive side. When I try to ...