Gentleman Mike
New Member
I've set up this SPH10K48SP and it works great, very impressive unit for the price except for one thing. It makes a downstream rack mounted APC SmartUPS give off a buzzing noise, like possibly from a transformer, whenever power is coming from the SunGold inverter. It still works, but the buzzing is constant until the SunGold goes back into grid passthrough mode.
What could cause this? I looked at the inverter output with a cheap handheld oscilloscope I have, and it looks like a clean sine wave to my eyes, but could there be some hidden harmonics causing the issue? If so, could this damage certain appliances in my house, like say the furnace blower, fridge compressor or sump pump motor?
Is it damaging the APC UPS, or does the annoying buzz have no ill effect functionally?
It doesn't have anything to do with the grounding or anything like that. The UPS would complain with a site wiring fault if there was a ground issue.
EDIT: At work we are also experimenting with using the 5 kW SunGold unit as a replacement for a standard UPS in the server room, and I also noticed the same issue when plugging our existing APC UPS there into the inverter.
What could cause this? I looked at the inverter output with a cheap handheld oscilloscope I have, and it looks like a clean sine wave to my eyes, but could there be some hidden harmonics causing the issue? If so, could this damage certain appliances in my house, like say the furnace blower, fridge compressor or sump pump motor?
Is it damaging the APC UPS, or does the annoying buzz have no ill effect functionally?
It doesn't have anything to do with the grounding or anything like that. The UPS would complain with a site wiring fault if there was a ground issue.
EDIT: At work we are also experimenting with using the 5 kW SunGold unit as a replacement for a standard UPS in the server room, and I also noticed the same issue when plugging our existing APC UPS there into the inverter.
Last edited: