SW 4024 Trouble Qualifying AC with Autotransformer On

MrM1MrM1 Registered Users Posts: 475 ✭✭✭
Last year, after going to great lengths to balance my loads in my panel, I still was not have great success with the Conext SW 4024 AC Support mode.  I had the chance to install an Outback Autotransformer (for free) and the results where a bit better.  AC Support mode worked pretty well.  Loads balanced.   Example: 120v 1050 Watt Water heater element on L1.  Without Autotransformer: L1 = 8.9 amps / L2 = 0 amps. With AT: L1 = 5.5 amps / L2 = 3.4 amps (just tested again today).
I also have wanted to put the AC in from grid to the SW on a timer,  so that during the day I could run totally off grid and at night grid I could run the loads off the SW's AC support mode.  A few days ago I installed a 120v Timer that controlled a 240v 40amp contactor.  So far so good.  Works as expected. 
On the 2nd day the system was running off grid, and at the set time,  the timer turned the AC in from grid on ... and i notice my lights flash on/off 2 or 3 times over a few seconds.  I did not like that.  So this morning I am checking everything. 
Here is what I noticed:
- The issue is not the timer or the new contactor.  Working fine.  Test both with L1/L2 voltage and not with L1/L2 voltage to insure contactor was closing.
But here is the Problem.  With no loads on the SW (except self consumption)
- With the Autotransformer switched OFF (it has it's own breaker), I apply Grid AC and the SW Qualifies AC in no problem in the 10 seconds as set in the SW and the physical sound of the transfer is very smooth, a single click of a contactor inside the SW.  The SW's AC support mode is on, and I then turn the the water heater load on but it is not balanced at all.
- BUT when the Autotransformer is ON,  And I apply Grid AC with no loads on the SW, the SW goes to 10 seconds and there is a load click inside the SW,  (I assume the AC in contactor) but it is still trying to Qualify the AC.  The SW waits another 10 seconds and tries again.  Click,  sometimes it Qualifies, sometimes the SW is still trying to Qualify.  Waits another 10 seconds and tries again.  AC Qualifies.  
- The AC is there,  I can see a reading off it in the Combox on L1 and L2 it is just not qualified.  And each time the SW tries to qualify the AC it just makes a load click. 
- Once the AC finally qualifies, the SW reports AC Good and everything works as expected.
I tested this 3 times today.  With the Autotransformer on and no loads on the SW,  Sometimes the SW Qualifies the AC the first time,  sometimes the second attempt,   and the last time I tried it,  the SW took 3 attempts before the AC would Qualify.  Each attempt with the sound of a load click coming from within the SW which I assume is the AC in Contactor as I watched and waited.
My assumption is this is hard on the SW.  Why would this be happening with the Autotransformer on and no loads, but not with the AT off?  I also assume if there were loads,  it would be even more difficult and harder on the Contactor inside the SW. 
Ideas on how to correct this.  Or should I just leave the AT off if using the timer and when powering on Grid AC in?   But if yes,  again why is this happening (so that I can understand).

REC TwinPeak 2 285W 3S-3P 2.6kW-STC / 1.9kW-NMOT Array / MN Solar Classic 150 / 2017 Conext SW 4024 Inverter latest firmware / OB PSX-240 Autotransfomer for load balancing / Trojan L16H-AC 435Ah bank 4S connected to Inverter with 7' of 4/0 cable / 24 volt system / Grid-Assist or Backup Solar Generator System Powering 3200Whs Daily / System went Online Oct 2017 / System, Pics and Discussion

Comments

  • MrM1MrM1 Registered Users Posts: 475 ✭✭✭
    edited September 16 #2
    Here is how the AT is wired to the system:  (note the load watts in the examples are not actual and I realize are listed too hi for the SW)


    REC TwinPeak 2 285W 3S-3P 2.6kW-STC / 1.9kW-NMOT Array / MN Solar Classic 150 / 2017 Conext SW 4024 Inverter latest firmware / OB PSX-240 Autotransfomer for load balancing / Trojan L16H-AC 435Ah bank 4S connected to Inverter with 7' of 4/0 cable / 24 volt system / Grid-Assist or Backup Solar Generator System Powering 3200Whs Daily / System went Online Oct 2017 / System, Pics and Discussion
  • EstragonEstragon Registered Users Posts: 4,118 ✭✭✭✭✭
    May or may not be related, but my x240 (wired for step-up) takes a few seconds to stabilize when first turned on. If the submersible pump load is turned on during those first few seconds, odds are the gfci on the load circuit trips.

    Just guessing, but could it be that the x240 transformer core is depowered briefly during the transfer switch operation, and this is sometimes causing problem for the inverter qualifying the AC input?
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • MrM1MrM1 Registered Users Posts: 475 ✭✭✭
    Yes that about seems like what it is doing.  And I would not think it is good that it is "slamming" the SW contactors (in my case not yours) 1 to 3 (or maybe more) times before it Qualifies the AC. 
    REC TwinPeak 2 285W 3S-3P 2.6kW-STC / 1.9kW-NMOT Array / MN Solar Classic 150 / 2017 Conext SW 4024 Inverter latest firmware / OB PSX-240 Autotransfomer for load balancing / Trojan L16H-AC 435Ah bank 4S connected to Inverter with 7' of 4/0 cable / 24 volt system / Grid-Assist or Backup Solar Generator System Powering 3200Whs Daily / System went Online Oct 2017 / System, Pics and Discussion
  • MrM1MrM1 Registered Users Posts: 475 ✭✭✭
    Well I guess it's not the autotransformer with the AT off the CSW just tried to qualify AC and it took 5 attempts. Seems like something is wrong wrong. Ideas? How do I start a warranty case? 
    REC TwinPeak 2 285W 3S-3P 2.6kW-STC / 1.9kW-NMOT Array / MN Solar Classic 150 / 2017 Conext SW 4024 Inverter latest firmware / OB PSX-240 Autotransfomer for load balancing / Trojan L16H-AC 435Ah bank 4S connected to Inverter with 7' of 4/0 cable / 24 volt system / Grid-Assist or Backup Solar Generator System Powering 3200Whs Daily / System went Online Oct 2017 / System, Pics and Discussion
  • EstragonEstragon Registered Users Posts: 4,118 ✭✭✭✭✭
    Can you widen the qualification values (voltage and frequency) on the grid AC input?  If you can, I'd try widening voltage a bit. Grid AC defaults might be a bit narrow depending on local grid. 

    I'd also check and re-torque the physical connection
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • MrM1MrM1 Registered Users Posts: 475 ✭✭✭
    edited September 18 #7
    Not sure I exactly know what you mean by widen. Right now now it's set

    AC 1 low voltage = 95
    AC 1 hi voltage = 135
    AC 1 low frequency = 55
    AC 1 hi frequency = 65
    AC 1 Qualify time = 10 sec 

    My grid voltage at the SW is about 118v

    REC TwinPeak 2 285W 3S-3P 2.6kW-STC / 1.9kW-NMOT Array / MN Solar Classic 150 / 2017 Conext SW 4024 Inverter latest firmware / OB PSX-240 Autotransfomer for load balancing / Trojan L16H-AC 435Ah bank 4S connected to Inverter with 7' of 4/0 cable / 24 volt system / Grid-Assist or Backup Solar Generator System Powering 3200Whs Daily / System went Online Oct 2017 / System, Pics and Discussion
  • EstragonEstragon Registered Users Posts: 4,118 ✭✭✭✭✭
    That seems plenty wide to me.
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • MrM1MrM1 Registered Users Posts: 475 ✭✭✭
    Seems like is something going wrong with the physical contactor inside the SW 
    REC TwinPeak 2 285W 3S-3P 2.6kW-STC / 1.9kW-NMOT Array / MN Solar Classic 150 / 2017 Conext SW 4024 Inverter latest firmware / OB PSX-240 Autotransfomer for load balancing / Trojan L16H-AC 435Ah bank 4S connected to Inverter with 7' of 4/0 cable / 24 volt system / Grid-Assist or Backup Solar Generator System Powering 3200Whs Daily / System went Online Oct 2017 / System, Pics and Discussion
  • MrM1MrM1 Registered Users Posts: 475 ✭✭✭
    I just installed this 240v contactor that has a 120v coil. I'm triggering the contactor with a 120v single pole timer. Could this be the issue? 
    REC TwinPeak 2 285W 3S-3P 2.6kW-STC / 1.9kW-NMOT Array / MN Solar Classic 150 / 2017 Conext SW 4024 Inverter latest firmware / OB PSX-240 Autotransfomer for load balancing / Trojan L16H-AC 435Ah bank 4S connected to Inverter with 7' of 4/0 cable / 24 volt system / Grid-Assist or Backup Solar Generator System Powering 3200Whs Daily / System went Online Oct 2017 / System, Pics and Discussion
  • MrM1MrM1 Registered Users Posts: 475 ✭✭✭
    I'll test it in the morning with the contactor removed. But all connections are tight 
    REC TwinPeak 2 285W 3S-3P 2.6kW-STC / 1.9kW-NMOT Array / MN Solar Classic 150 / 2017 Conext SW 4024 Inverter latest firmware / OB PSX-240 Autotransfomer for load balancing / Trojan L16H-AC 435Ah bank 4S connected to Inverter with 7' of 4/0 cable / 24 volt system / Grid-Assist or Backup Solar Generator System Powering 3200Whs Daily / System went Online Oct 2017 / System, Pics and Discussion
  • EstragonEstragon Registered Users Posts: 4,118 ✭✭✭✭✭
    So if I'm understanding this right, there's a timer switching 240v grid on/off, triggered by a 120v coil?  So where does the 120v come from?




    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • MrM1MrM1 Registered Users Posts: 475 ✭✭✭
    edited September 18 #13
    The inverter provides the power for the timer and sends the 120v to the coil of the contactor. 
    REC TwinPeak 2 285W 3S-3P 2.6kW-STC / 1.9kW-NMOT Array / MN Solar Classic 150 / 2017 Conext SW 4024 Inverter latest firmware / OB PSX-240 Autotransfomer for load balancing / Trojan L16H-AC 435Ah bank 4S connected to Inverter with 7' of 4/0 cable / 24 volt system / Grid-Assist or Backup Solar Generator System Powering 3200Whs Daily / System went Online Oct 2017 / System, Pics and Discussion
  • MrM1MrM1 Registered Users Posts: 475 ✭✭✭
    edited September 18 #14
    Let me guess... An odd loop?  When the SW tries to make the transfer from inverter to grid , it momentarily for a split instant opens my new contactor because I'm momentarily losing my 120v to the coil ? I then momentarily lose my 240v AC in to the inverter, Thus preventing the AC from qualifying?
    REC TwinPeak 2 285W 3S-3P 2.6kW-STC / 1.9kW-NMOT Array / MN Solar Classic 150 / 2017 Conext SW 4024 Inverter latest firmware / OB PSX-240 Autotransfomer for load balancing / Trojan L16H-AC 435Ah bank 4S connected to Inverter with 7' of 4/0 cable / 24 volt system / Grid-Assist or Backup Solar Generator System Powering 3200Whs Daily / System went Online Oct 2017 / System, Pics and Discussion
  • mcgivormcgivor Solar Expert Posts: 3,126 ✭✭✭✭✭
    Powerr both the contactor coil and timer with grid power to eliminate the odd behavior.
    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery bank 
    Second system 1890W  3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah FLA 24V nominal used for water pumping and day time air conditioning.  
    5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
  • MrM1MrM1 Registered Users Posts: 475 ✭✭✭
    edited September 18 #16
    Headed there right now. Seems like that's what it is 
    REC TwinPeak 2 285W 3S-3P 2.6kW-STC / 1.9kW-NMOT Array / MN Solar Classic 150 / 2017 Conext SW 4024 Inverter latest firmware / OB PSX-240 Autotransfomer for load balancing / Trojan L16H-AC 435Ah bank 4S connected to Inverter with 7' of 4/0 cable / 24 volt system / Grid-Assist or Backup Solar Generator System Powering 3200Whs Daily / System went Online Oct 2017 / System, Pics and Discussion
  • MrM1MrM1 Registered Users Posts: 475 ✭✭✭
    edited September 18 #17
    mcgivor said:
    Powerr both the contactor coil and timer with grid power to eliminate the odd behavior.
    Contactor coil now powered by Grid AC and this seems to have solved the issue.  After switch I tested it 3 times.  Once with  Autotransformer off and twice with the AT on.  All 3 times the SW transitioned to Grid AC and Qualified first attempt in typical fashion.  I will try it with a 1000W resistive load in about an hour,  but so far this transfer loop seemed to be the issue.
    Note to Self:  Do NOT run your Grid AC in Timer/Contactor from  your Hybrid Inverter AC out.
    REC TwinPeak 2 285W 3S-3P 2.6kW-STC / 1.9kW-NMOT Array / MN Solar Classic 150 / 2017 Conext SW 4024 Inverter latest firmware / OB PSX-240 Autotransfomer for load balancing / Trojan L16H-AC 435Ah bank 4S connected to Inverter with 7' of 4/0 cable / 24 volt system / Grid-Assist or Backup Solar Generator System Powering 3200Whs Daily / System went Online Oct 2017 / System, Pics and Discussion
  • mcgivormcgivor Solar Expert Posts: 3,126 ✭✭✭✭✭
    Powering from different sources can often lead to confusion, another day another lesson learned, keep that in the random access part of your computer.....brain.
    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery bank 
    Second system 1890W  3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah FLA 24V nominal used for water pumping and day time air conditioning.  
    5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
  • MrM1MrM1 Registered Users Posts: 475 ✭✭✭
    No problem now with the AT turned on even with a 1000W load on the system when the transfer takes place.  Looks like moving the new timer's power source and supply from the inverter to the direct grid connection solved it.  Thanks all.
    REC TwinPeak 2 285W 3S-3P 2.6kW-STC / 1.9kW-NMOT Array / MN Solar Classic 150 / 2017 Conext SW 4024 Inverter latest firmware / OB PSX-240 Autotransfomer for load balancing / Trojan L16H-AC 435Ah bank 4S connected to Inverter with 7' of 4/0 cable / 24 volt system / Grid-Assist or Backup Solar Generator System Powering 3200Whs Daily / System went Online Oct 2017 / System, Pics and Discussion
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