question

Elimac avatar image
Elimac asked

Use of soft starter with Multiplus and AC Motor

I 'm curious if anyone has had any success (or not too!) in using a Soft Starter on the output of Inverters /input of loads, specially with those loads that have high inrush current.

I have a 2kW water pump motor that really stresses my 2x 3kVA Multipluses parallel setup. The inrush current is too much. But if I could insert a softstarter, for example some a model from this catalogue:

https://www.tme.eu/Document/7343294bf62785612edaf3b14e573997/ATS01-EN.pdf

Maybe I could power the motor with my offgrid solar gear. Which model would be best? Is there any drawbacks I'm missing out?


MultiPlus Quattro Inverter Charger
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3 Answers
wkirby avatar image
wkirby answered ·

This would probably work pretty well. I use a VFD for some of my machine tools and even my baby MultiPlus likes it quite a lot.

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Elimac avatar image Elimac commented ·
Thanks @WKirby! VFD and Softstarters are different animals... are you implying softstart will also be a good bet? By the way, what is the relationship between the peak current of your load and the peak current of the MP you managed to use?
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Kevin Windrem avatar image
Kevin Windrem answered ·

A soft start for your pump should help significantly. The one in your like would require some manual adjustments but should at least help with startup surge.

I have a Multi Compact in my RV and installed a MicroAir soft start unit on the air conditioner. I was able to start the air conditioner on inverter without the soft start but it was a struggle. Now the Multi handles the startup much better. I've also tested this when running the RV on a 2000 VA generator with the Multi bypassed and the air conditioner starts even with ECO on.

I've since installed a similar unit on my home air conditioner and am able to start it on a 5500 VA generator. Before the soft start, the generator would overload and drop the loads.

The MicroAir units are self learning but may be specific to air conditioner/heat pump units. They are designed for capacitor start/run motors. You might check with them about using one on your pump.


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Luit Jan avatar image
Luit Jan answered ·

Hi all,

I have tried two different types of Softstarters but both destroyed my 230V net. It was installed after the Quattro 5000.

Does anybody have good experience with a softstarter? I now start the Pump (1,5kW) without and this is giving a dip in the net.

What type of softstarter should be used?


Thanks

Luit Jan

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manta avatar image manta commented ·

You can look into a simple NTC softstarter with a bypass relay. Not sure if it will work for your motor but use a Ametherm MS35-20010 NTC for my isolation transformer (5Kva) which was tripping the breaker on startup, now i can startup without tripping a normal 230v 10A shore breaker. After a second there is a timer relay and a (AC3) bypass relay which activates so the NTC can cool and does not create a lot of parasitic load & makes the unit restartable if needed. The NTC stays connected paralell and stay's at ambient temp after cooling. Cheap and simple solution.

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