Hello everybody,
I'm Fabio and I'm writing from the south of IT about, as said in the title, powering a solar string inverter with a 300VDC supply.
Somebody asked to try a fix for this one (since I've yet found a solution to repair some similar inverters).
They told me that there's no response when the apparatus has fed with its panel string, but I'm not sure of this. I don't have the original solar panels to test it safely.
I've checked the majority of things could be replaced but everything seems to be OK, so I'm expecting a faulty board and/or EEPROM.
I don't have a bench test supply and the inverter powers on with max 1000V @ 12A so I'm wondering the best way to turn it on and receive a response from serial port is:
- commonly rectify the main AC lab supply with a diode bridge 1N4007 and capacitor (150-220mF 400V) to get out 310VDC (checking on scope the correct voltage and supply nature before connecting the load)
- a 1/4W 820k resistor paralleled with the capacitor will ensure its discharge when the circuit will be disconnected from main power source.
- the rectifier assembly must be located in a well isolated box, no live wires cause the cap output comes directly into the original inverter input connectors - according to the manual, these connectors seems to be enough to limit input current.
- I can provide an automatic magnetothermal switch rated 400V 8A before the rectifier bridge and an isolator switch w/fuse between the cap and the inverter to provide "current limiting" (it wouldn't exceed 10A).
- for sure I will not connect the output grid back into the mains until I'm not sure that the apparatus could provide enough isolation. But seems to be unnecessary because the inverter will give me a grid fault error.
Knowing how much could be unsafe to run rectification on a 250VAC source and supposing to pay so much attention when going to apply it, I'm asking you for further suggestions and consideration about, and specifically: current limiting tips on the circuit, the possibility to get output grid re-connection and any kind you're thinking I've not yet took into account
Thanks in advance
I'm Fabio and I'm writing from the south of IT about, as said in the title, powering a solar string inverter with a 300VDC supply.
Somebody asked to try a fix for this one (since I've yet found a solution to repair some similar inverters).
They told me that there's no response when the apparatus has fed with its panel string, but I'm not sure of this. I don't have the original solar panels to test it safely.
I've checked the majority of things could be replaced but everything seems to be OK, so I'm expecting a faulty board and/or EEPROM.
I don't have a bench test supply and the inverter powers on with max 1000V @ 12A so I'm wondering the best way to turn it on and receive a response from serial port is:
- commonly rectify the main AC lab supply with a diode bridge 1N4007 and capacitor (150-220mF 400V) to get out 310VDC (checking on scope the correct voltage and supply nature before connecting the load)
- a 1/4W 820k resistor paralleled with the capacitor will ensure its discharge when the circuit will be disconnected from main power source.
- the rectifier assembly must be located in a well isolated box, no live wires cause the cap output comes directly into the original inverter input connectors - according to the manual, these connectors seems to be enough to limit input current.
- I can provide an automatic magnetothermal switch rated 400V 8A before the rectifier bridge and an isolator switch w/fuse between the cap and the inverter to provide "current limiting" (it wouldn't exceed 10A).
- for sure I will not connect the output grid back into the mains until I'm not sure that the apparatus could provide enough isolation. But seems to be unnecessary because the inverter will give me a grid fault error.
Knowing how much could be unsafe to run rectification on a 250VAC source and supposing to pay so much attention when going to apply it, I'm asking you for further suggestions and consideration about, and specifically: current limiting tips on the circuit, the possibility to get output grid re-connection and any kind you're thinking I've not yet took into account
Thanks in advance
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