Morning to you all.

i am new to this forum, and i must appologise for my poor english, ons Boere sukkel maar met engels...

I have installed two axperts inverters in paralel, in Centurion with 20 x 250W panels, 780 a/h 2V cells and is connected to mains. Inverter is set to SBU and works wonderful. The heat pump keeps on tripping my mains breaker (not EL), not when the heat pump start running, but only when the inverter changes from one enegry source to another. The heat pump is only a 1100w unit. Does anybody have an idea how to rectify this? Faulty breaker?

 

Regards

Theuns

Welkom Theuns, nee wat, jy sukkel glad nie. 

Sal graag wil help maar die ander mense weet meer.

So when the inverter switches to grid while the heat pump is running, the main breaker trips? Do I understand you correctly?

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Might also help to understand what type the main breaker is. Thermal or magnetic. I doubt it's thermal given the response.

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Okay, so I read up on that a bit. Most breakers are probably a combination of magnetic and thermal, so they can run up to 40% above their rating for as much as an hour before tripping. The point is to avoid nuisance tripping, but still trip if there is a sharp spike or a prolonger overload.

It seems to me the trouble here is nuisance tripping. Transferring the load back onto the grid possibly creates a sufficiently large spike that the magnetic side of the breaker kicks in. So the obvious thing to do -- if you want to do this properly and all -- is to stick an oscilloscope or a good multimeter that can chart things on there, and see what the spike is like and how bad it really is. Then in all likelihood, you're going to end up replacing the breaker.

http://electronicdesign.com/electromechanical/choosing-wrong-circuit-breaker-waste-money-or-worse

Check, and double check the earth on the inverters and on the heatpump. If there's a loose earth wire it could do the same thing. Or you could use "D curve" circuit breakers" as it can handle these spikes a bit easier. 6KVA should do. 

Morning to you all.

i have isolated the problem to the heatpump, by disconnecting the heatpump at the solar db and moving the feed wires to the old eskom db. this solves the problem, but the client doesn't whats the heatpump on solar. The loose earth i have double checked, and i replaced he supply wire from db to source.

 

i have that of replacing the breaker, i think that it is an ac/dc brand. 

 

thank you all for the advise, especially Plonkmaster! Will put and proper multi meter to it.

 

Boeregroete!

Om 'n ossiloskoop te hê is 'n fees. En dis so bekostigbaar tweedehands. Al wat ek nog graag wil hê is 'n digital storage scope :-) Of 'n goeie Fluke DMM.

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6 hours ago, plonkster said:

Om 'n ossiloskoop te hê is 'n fees. En dis so bekostigbaar tweedehands. Al wat ek nog graag wil hê is 'n digital storage scope :-) Of 'n goeie Fluke DMM.

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Net jammer daai goed  is so moer duur...

Speaking of that, one thing that makes no sense to me is single shot trigger on an ordinary analog scope. Sure, on a storage score you can capture the event, but on the non-storage kind all that does is tell you that there was a trigger. It's way too fast to observe.

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2 hours ago, plonkster said:

Speaking of that, one thing that makes no sense to me is single shot trigger on an ordinary analog scope. Sure, on a storage score you can capture the event, but on the non-storage kind all that does is tell you that there was a trigger. It's way too fast to observe.

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It's limited, but handy to see which pin on a PCB caused the trigger.