Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [soft-starter]

15 questions
4
votes
2 answers

12 V Soft-Start circuit

I'm struggling designing a soft-start circuit for my project. It's 12 V with up to 500 mA load. I'm looking for a ~1000 ms ramp-up time from 0 to 12 V. This is the circuit I have designed, which seems to work in the simulator, but I may have…
Maciej Swic
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2 answers

Soft start circuit problem

I am currently working on a soft-start circuit. The picture below is my schematic. It worked fine in simulation and even in a real circuit. But after several times, turn on and off the power source (My power DC source: V=24V, 290W), the MOSFET dies…
Lan Tran
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2
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3 answers

TRIAC keeps failing

IMPORTANT UPDATE (Update 6), scroll down to see. I have been trying to make an AC (air conditioner) soft starter for my home AC unit. I have built the following circuit and connected it to my AC unit compressor. As soon as the AC starts the TRIAC…
Oli
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Soft starter for AC motors

I want to build an AC motor soft start. The way I found is to regulate the voltage from 0 to 220 V (within 2 seconds) to eliminate the inrush current. I did it using Arduino to generate PWM to drive a TRIAC. Is there any way to generate the required…
jihad.khorfan
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Design or selection of a capacitive-load soft start circuit

A circuit to soft-start, a.k.a. slew-limit, the charging of a 220 uF capacitor Cf at a maximum current in the neighbourhood of 300 mA. Cf is a filter cap preceding a further SMPS stage. My plan so far is to use an ESL227M035AG8AA, an aluminum…
Reinderien
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1 answer

Control PMOS or NMOS for Soft Start with Variable Voltage Source (Battery or known series string of solar)?

I have a soft start circuit that looks like so: The load will actually be a synchronous boost/buck converter, and ultimately this could also have an AC source instead of just DC and have a rectifier put inline as well. The issue is that this works…
James Hancock
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3 answers

Inrush control transient at power on

I have a circuit with a not-so-small capacitor on the supply and I need to reduce the inrush surge; as a matter of fact the power supply breaks after a while (these cinese supplies are not fun) I followed ON Semi AND9093/D (which is in fact very…
Lorenzo Marcantonio
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3 phase controlled soft starter and motor vibration

I want to make a soft starter for 3 phase induction motors. TRs are SCR pairs and ZCs are the zero-cross timing respect to line voltages (400V), not phase voltages (230V). I control the firing angle of the SCRs with their ZC timing: TR1 with…
MP3
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1 answer

Solid State Relay for Large Inductive Load

I have an old, transformer-based welding machine, which is rated to draw about 70A at 240V, at full output. It uses an electro-mechanical relay (contactor) to energize the main power transformer, and depending on the point in the AC cycle that the…
Elkvis
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Why is this precharge circuit not functioning?

Although this question sounds basic but, I have been trying to implement this precharge circuit to safely turn on the inverter without overloading the system, however especially when I powered it on, the relay turned on in no time(didn't seem the…
Hazardous Voltage
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Wrong output with DC soft start

I have a Pi Pico project I am working on and I ran into a hiccup. I have a 12VDC soft start that I used from this thread. I pretty much used the same thing, but I changed the MOSFET to IRF9620 . I am using the soft start because the datasheet of…
peterman
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Why do some transformers trip circuit breaker. Eg a ups transformer. I need a soft start resistor details

I need a soft start for a ups transformer. Because when I power it with 230v ac it trips the breaker. I need a diagram to build my own soft start circuit.
sylivanos oketcho
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Soft-start design and performant with short-circuit test

I am working on a soft-start for a capacitive load. I using module QSB40024S24 to create 24V output. At first, I allowed the output of the module to connect directly to a capacitor array (21.4mF in total) in parallel with the load. So you can…
Lan Tran
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Why does this oscillator not work with a voltage less than 9 V?

By chance of my research and simulations and various tests, I found the diagram of an oscillator with strange behavior. All the oscillators (quasi) that I have encountered work whatever the supply voltage is (in principle within the limits generally…
Antonio51
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Soft Start for AC incandescent lamp

i want to make a soft starter for incandescent lamp. i have seen some magical dimmer or Russian soft start device which are not available near me. i found some diagram of the Russian soft start device but could not find the required КР1182ПМ1…
user284562