Schneider XW Pro and Modified Sine Wave Generators

[ElectricIslander]

Inverter generators synthesize their output by switching in discrete steps. High quality inverters have more steps (for example the Honda 3000is has 49 steps). A "modified sine wave" is often approximated by many less steps in lower quality generators and will thus have higher total harmonic distortion (THD).

 

[scottcoppervalley]

Do not use a modified sinewave input to a hybrid sinewave inverter.

Hybrid inverters synchronize to AC input before closing connect relay and inverter runs in parallel with AC input.

Paralleling a hybrid sinewave inverter from a modified sinewave source input will cause high current spikes in both inverter and MSW source.

I am experiencing those high current spikes that you are referring to. I have an Onan 10 HDKAG spec J, using a 305-0875-04 voltage regulator. I have a Schnieder XW pro 6.8. I have been data logging at 1 second intervals to try to troubleshoot. The Onan seems solid and consistently puts out voltage around 122 each leg at around 62 hertz. Just replaced voltage regulator, armature, brushes because it had to be a generator issue. At house in bypass mode (meaning bypassing the inverter) I get good clean energy from the generator. When routed through the inverter, I am getting spikes up to 137v on each line. Which is where I set my cut off for disqualification.
At little more background... My old inverter XW plus 5548 died and I upgraded to the XW pro. That pro produced the spikes and fried some of my more sensitive electronics in the house. Schnieder called the inverter defective and sent me a replacement. Same issues with new inverter. Onan says my generator is fine and they advise me that my sinewave is "pure". So not the modified sinewave you caution against. The system runs fine using my cheaper 6,500 watt gas backup generator. Hook up the Onan and bad things happen. It seems like my Onan is just not compatible, but according to Schnieder specs that is not the case. Triple checked the wiring (and re-ran all the wiring). I have talked to a lot of folks who say this just shouldn't be happening. Yet.
So any help would be appreciated.

 

[ElectricIslander]

I am experiencing those high current spikes that you are referring to. I have an Onan 10 HDKAG spec J, using a 305-0875-04 voltage regulator. I have a Schnieder XW pro 6.8. I have been data logging at 1 second intervals to try to troubleshoot. The Onan seems solid and consistently puts out voltage around 122 each leg at around 62 hertz. Just replaced voltage regulator, armature, brushes because it had to be a generator issue. At house in bypass mode (meaning bypassing the inverter) I get good clean energy from the generator. When routed through the inverter, I am getting spikes up to 137v on each line. Which is where I set my cut off for disqualification.
At little more background... My old inverter XW plus 5548 died and I upgraded to the XW pro. That pro produced the spikes and fried some of my more sensitive electronics in the house. Schnieder called the inverter defective and sent me a replacement. Same issues with new inverter. Onan says my generator is fine and they advise me that my sinewave is "pure". So not the modified sinewave you caution against. The system runs fine using my cheaper 6,500 watt gas backup generator. Hook up the Onan and bad things happen. It seems like my Onan is just not compatible, but according to Schnieder specs that is not the case. Triple checked the wiring (and re-ran all the wiring). I have talked to a lot of folks who say this just shouldn't be happening. Yet.
So any help would be appreciated.

You might try adding a purely resistive load to the generator (a 200 Watt halide work light, or a small AC 500W heater, heat gun etc.) so that is slightly loaded down before it connects to the inverter. The pure resistance will damped down inductive ringing. If that works you will know a bit more about what the problem might be.

The Smokstak forum (https://www.smokstak.com/forum/forums/onan-generators.1/ ) has an Onan section which has great resources on Onan Generators. (I have an old single cylinder, propane Onan of 6.5 kW and found their advice excellent), They will be able to help, I'm sure that your generator will be able to connect to the XWPro.

Good luck and keep us posted!

 

[Hedges]

If inductive ringing is a problem and resistive load snubs it, try a series RC circuit. Hopefully can be tuned to work while dissipating much less power.

 

[scottcoppervalley]

You might try adding a purely resistive load to the generator (a 200 Watt halide work light, or a small AC 500W heater, heat gun etc.) so that is slightly loaded down before it connects to the inverter. The pure resistance will damped down inductive ringing. If that works you will know a bit more about what the problem might be.

The Smokstak forum (https://www.smokstak.com/forum/forums/onan-generators.1/ ) has an Onan section which has great resources on Onan Generators. (I have an old single cylinder, propane Onan of 6.5 kW and found their advice excellent), They will be able to help, I'm sure that your generator will be able to connect to the XWPro.

Good luck and keep us posted!

Will give her a try, as per your recommendation. Thanks.

 

[scottcoppervalley]

A little update. Yes a 1500 watt heater, greatly dampened or fixed the issue. But.. while trying to figure out what/how the capacitors should be wired in. I purchased a costco $900. gen. Same issue. Except the heater trick doesn't work. There were big voltage spikes and fluctuations of VAR from -2583 to 1629 eventually the inverter knocked the new gen off line (as usual). New generator works perfect when bypassing the inverter. I THINK it might be the device operating state setting. On a generator that was not functioning correctly that state shows up as 'backup' and with a generator that worked properly (the older 6,800 costco special with a honda) the inverter setting shows "generator tie". It think that setting controls the tie method for the sinewaves. Something about it l extracted from Bing chat. ". It needs to synchronize the phase and frequency of the incoming AC signals to ensure they can be combined without causing interference..." I don't believe I can change that setting.
I was over my head before. My preference would be for Schneider to own up and have an engineer figure this out, but that's not going to happen. Does it seem like I am looking the right direction?

This is the new gen. Have no idea about what type of sine wave.

Firman 7500W Running / 9400W Peak Tri Fuel Generator​

Item 1300533

Model T07571

 

[scottcoppervalley]

Update. Fixed the issue. No thanks to Schneider. In fact they still have no idea. Backed the firmware to v1.11 build 0049. Major bug in the latest firmware 1.19. Local energy store had same issues as me and came up with the firmware solution. Schneider needs to get on the ball before they burn someone's house down. During those voltage spikes, besides killing electronic equipment in the house the panel of the inverter was about 150 degrees f. No idea how hot it was internally. Please be clear, that firmware thing is a big deal. I don't recommend unless you have the SAME conditions as I. Even then, go through Schneider. Would hate to be the cause of some other electrical problems, since I am not an expert.