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Need cheap solution to stop inverter overload inductive load
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bigjoncoop:
Issue: inverter instantly goes into protection mode when AC compressor kicks on

Trying to find a cheap solution to help inverter overcome the large Spike when the compressor kicks on...  Such as a soft start I believe.

Youtubers Great Scott and electronicsNmore both have videos on a simple circuit to help with such a problem but I'm not 100% sure it will work with this application...

Great Scott's soft starter is made of a relay and a mosfet with a few other miscellaneous components.
www.instructables.com/How-to-Make-a-Softstarter

&

electronicsNmore's solution is using a couple of NTC current limiting thermistors.
https://youtu.be/1MPW1dqulWw

Am I correct in assuming that both of those Solutions only work immediately when the power is first turned on?

My air conditioner will first run the fan for a couple of minutes before kicking on the compressor. That is why I'm not sure if I threw those Solutions will work. I might be wrong though...

Can anyone else recommend a solution? Basically I need something that can stay in circuit and then provide a "buffer" for a brief second when the compressor kicks on. I was thinking like a large start capacitor on the output of the inverter but I'm just not sure.

I know there are soft starters available but they cost a couple hundred dollars

NiHaoMike:
Install a "hard start kit" on the compressor. You can also try turning down the voltage and frequency, such that the V/Hz ratio remains the same.
Stray Electron:


    I'm not sure that anything is really going to help.  Inverters just don't have much reserve current capacity, unlike the AC power line. Motors draw a LOT of amperage when starting. MANY times more than their running current.  My first suggestion would be to temporally run your motor from the normal AC power line and to use an amp meter (an analog one, since digitals aren't fast enough) and watch the current draw when you motor starts and that will give you some idea of the kinds of currents that you're dealing with.
AVGresponding:

--- Quote from: bigjoncoop on July 22, 2023, 12:03:51 am ---I was thinking like a large start capacitor on the output of the inverter but I'm just not sure.

I know there are soft starters available but they cost a couple hundred dollars

--- End quote ---

Why would you put the capacitance on the inverter output? If you want to do pfc that way, put it on the compressor motor in parallel. You don't need to achieve a pf of 1.0, just one close enough so that you don't exceed the VA rating.
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