Inverter automatic start

Discussion in 'The Projects Forum' started by Peter Moll, Nov 27, 2014.

  1. Peter Moll

    Thread Starter New Member

    Nov 27, 2014
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    0
    Hi,

    I am looking for a solution to automatically start an inverter when a load is applied.

    The background is I have an off grid home that I am powering with a PV system that I had a 35000W pure sine wave inverter connected to.

    Unfortunately an insect committed suicide inside the inverter and the driver circuit was damaged.

    As this was my only AC source I was without power for essential appliances. After reflecting on the issue I have decided to restructure the AC supply with redundancy in mind.

    Rather than rely on one large inverter I have divided the system up into smaller 'circuits', some only need modified AC and others need pure sine wave.

    I have purchased a couple of modified wave inverters to run things like the computer, household pressure pump, chargers and low power appliances.

    For some reason the washing machine will not run off the 7500W generator but worked fine with the old 3500W inverter, so I have purchase a 2500w pure sine wave inverter for that.

    As it and the inverters for the household pressure pump are not used constantly and they are located in an inconvenient location I am looking for a way to start the inverters when an appliance is turned on.

    I have seen this,
    ,
    and have emailed the company to enquire about a retro fit version but have not received a reply as yet.

    I have been searching the net for similar products to no avail.

    So I was hoping someone here might be able to help.

    Thanks
    Peter
     
  2. nsaspook

    AAC Fanatic!

    Aug 27, 2009
    2,910
    2,173
    Use quality pure sine inverters with a internal idle circuit. I have a PRO-watt SW2000 with an auto idle current of less than 0.4A when the load drops below 20w. A external circuit to power cycle the DC input will work but I don't like dead switching high-power electronics off/on frequently as this is usually the time when a inrush surge will smoke some internal part or the cooling fans shutdown while the unit is still very hot from a heavy load and a huge DC rated contractor/relay has to be a little expensive

    http://forum.allaboutcircuits.com/threads/automatic-off-on-switch-for-inverter.24608/
     
    Last edited: Nov 27, 2014
  3. Peter Moll

    Thread Starter New Member

    Nov 27, 2014
    6
    0
    Thanks,

    I've been looking at that thread, just trying to get my head around the schematic.

    "A external circuit to power cycle the DC input will work but I don't like dead switching high-power electronics off/on frequently as this is usually the time when a inrush surge will smoke some internal part or the cooling fans shutdown while the unit is still very hot from a heavy load and a huge DC rated contractor/relay has to be a little expensive"

    On off cycle for the washer would be max once per day, I could see where this could be a problem for the pump.

    I have also seen some inverters are offered with the auto switch option, but price range is out of my reach.

    Peter
     
  4. nsaspook

    AAC Fanatic!

    Aug 27, 2009
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    The PRO-watt SW2000 has a pretty good price for quality inverter.

    Output waveform:
     
  5. Peter Moll

    Thread Starter New Member

    Nov 27, 2014
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    Looks pretty good, but no auto on feature?
    I remember years ago while fencing in the Northern Territory the station manager could just flick the light switch and the genny would start up.
    sort of like your first reply I suppose.

    I'll keep looking at that circuit you referred to.
     
  6. nsaspook

    AAC Fanatic!

    Aug 27, 2009
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    It does have auto on from standby. (from low power idle ~0.33A and no power out to inverter on when a load >20w is connected)
     
  7. Peter Moll

    Thread Starter New Member

    Nov 27, 2014
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    Ok

    Missed that

    Thanks
     
  8. Peter Moll

    Thread Starter New Member

    Nov 27, 2014
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    Bugger,

    Only 12v

    I forgot to mention I'm on 24v.
     
  9. nsaspook

    AAC Fanatic!

    Aug 27, 2009
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    The Samlex line of inverters would be by choice for low idle power then but the price would be almost double the 12vdc versions at the same power.
    http://pdf.donrowe.com/pst_2000_12_24_spec_sheet.pdf
     
  10. Peter Moll

    Thread Starter New Member

    Nov 27, 2014
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    0
    OMG,

    The prices are double to triple that in Australia.

    Time for plan B
     
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