July 19, 20232 yr 9 hours ago, Scorp007 said: It would seem way out sizes create a fire risk. There are some regs out how far they can differ Got a link? My google-fu is letting me down.
July 19, 20232 yr 13 hours ago, Scorp007 said: What is interesting is we have a few APC UPSes in the office. Not the moment when the frequency goes below about 48.5 and above about 51.5Hz they would alarm and switch to battery power. In the last 4yrs I can confirm they have never switched to battery when on grid power. Measurements thus in 2 areas of Tshwane. On the other hand I have assisted with measuring the frequency of an over 50kW genny which we use and I alerted the owner of the genny that there are over 20 switches taking place daily when on genny power. We traced it down to a 3rd company sharing the genny when they start a specific load. The genny would move between 47.5 and 52.5Hz. I do think this is enough reason to belief the Eskom grid is fantastically stable from a frequency point of view. At least @Antonio de Sa and myself seem to measure the same frequency. I share my voltage graph before and after LS. My system is off when the grid is off. I think we must give credit to how the QOS is managed within Eskom. Many areas are not as lucky as some of us are. There will be havoc in ZA if the frequency goes to 54Hz with overloaded motors and other equipment. @Scorp007 here is my grid voltage before load shedding running SUB two inverters, about 1 V difference while running on the inverters, quite a big difference when running on grid, fluctuates quite allot. 14 hours ago, Scorp007 said: What is interesting is we have a few APC UPSes in the office. Not the moment when the frequency goes below about 48.5 and above about 51.5Hz they would alarm and switch to battery power. In the last 4yrs I can confirm they have never switched to battery when on grid power. Measurements thus in 2 areas of Tshwane. On the other hand I have assisted with measuring the frequency of an over 50kW genny which we use and I alerted the owner of the genny that there are over 20 switches taking place daily when on genny power. We traced it down to a 3rd company sharing the genny when they start a specific load. The genny would move between 47.5 and 52.5Hz. I do think this is enough reason to belief the Eskom grid is fantastically stable from a frequency point of view. At least @Antonio de Sa and myself seem to measure the same frequency. I share my voltage graph before and after LS. My system is off when the grid is off. I think we must give credit to how the QOS is managed within Eskom. Many areas are not as lucky as some of us are. There will be havoc in ZA if the frequency goes to 54Hz with overloaded motors and other equipment.
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