April 24, 20224 yr Wondering if a HF Sunsynk can start a pump motor? Lets assume a 12kW 3Ph sunsynk and a 5.5kW 3 Ph motor started on a VFD. The sunsynk can surge to twice its load for 10s (or so says the manual). Start up load on a 5.5k 3 phase motor on a VFD should be limited to about 2.5 to 3 times the motor rating i think. Lets assume it spikes to 3 times - so thats about 17kW for a few seconds. I would have thought it would take 2 x 12kW 3Ph sunsynks in parallel to safely do this but i have no idea how HF inverters cope with starting motors. Then there is the added complication of not being to add a genset to a paralleled setup of sunsynks. maybe Victron is the way to go with its beefy toroidal transformer ?
April 24, 20224 yr 27 minutes ago, Delta9 said: Wondering if a HF Sunsynk can start a pump motor? Lets assume a 12kW 3Ph sunsynk and a 5.5kW 3 Ph motor started on a VFD. The sunsynk can surge to twice its load for 10s (or so says the manual). Start up load on a 5.5k 3 phase motor on a VFD should be limited to about 2.5 to 3 times the motor rating i think. Lets assume it spikes to 3 times - so thats about 17kW for a few seconds. I would have thought it would take 2 x 12kW 3Ph sunsynks in parallel to safely do this but i have no idea how HF inverters cope with starting motors. Then there is the added complication of not being to add a genset to a paralleled setup of sunsynks. maybe Victron is the way to go with its beefy toroidal transformer ? VFDs usually have soft starting so it's highly unlikely that the rated current will spike by 2.5 - 3 times.
April 24, 20224 yr Author 40 minutes ago, Leshen said: VFDs usually have soft starting so it's highly unlikely that the rated current will spike by 2.5 - 3 times. Well i've never used one so no hard experience with them, but i thought that even with a slow start up the motor still has a surge, just a lot smaller. In your experience how much of a load would a 5.5kW water pump motor using a VFD put on the inverter during pump start up and will the sunsynk handle this ? Edited April 24, 20224 yr by Delta9
April 24, 20224 yr 2 hours ago, Delta9 said: Wondering if a HF Sunsynk can start a pump motor? Lets assume a 12kW 3Ph sunsynk and a 5.5kW 3 Ph motor started on a VFD. The sunsynk can surge to twice its load for 10s (or so says the manual). Start up load on a 5.5k 3 phase motor on a VFD should be limited to about 2.5 to 3 times the motor rating i think. Lets assume it spikes to 3 times - so thats about 17kW for a few seconds. I would have thought it would take 2 x 12kW 3Ph sunsynks in parallel to safely do this but i have no idea how HF inverters cope with starting motors. Then there is the added complication of not being to add a genset to a paralleled setup of sunsynks. maybe Victron is the way to go with its beefy toroidal transformer ? The 2.5-3 times current is related to the current the VFD can deliver to a load. Edited April 24, 20224 yr by Scorp007
April 24, 20224 yr 1 hour ago, Delta9 said: Well i've never used one so no hard experience with them, but i thought that even with a slow start up the motor still has a surge, just a lot smaller. In your experience how much of a load would a 5.5kW water pump motor using a VFD put on the inverter during pump start up and will the sunsynk handle this ? I'm not sure about a 5.5kw pump. I have a 1.5kw DAB Esybox and it starts up at 300w and ramping up to 1.5kw if necessary. So if it's a good quality VFD then it won't exceed 5.5kw.
April 25, 20224 yr Author 12 hours ago, Leshen said: I'm not sure about a 5.5kw pump. I have a 1.5kw DAB Esybox and it starts up at 300w and ramping up to 1.5kw if necessary. So if it's a good quality VFD then it won't exceed 5.5kw. That's interesting - how do you find the Esybox? I have just bought an Esybox mini, a Dtron3 submersible and 4 x Esybox diver submersibles to try out. The Esybox Mini and the Esybox divers have a VFD onboard, the Dtron 3 has no VFD. I bought those 3 types of pumps from DAB to see what works well among them. I am also looking at Grundfos pumps because they have a nice VFD for thier pumps with some nice features, but that's the next experiment after the DAB's. All of these need to be run via an electrical inverter - either battery based or AC coupled hence asking this question. I know Victron is a safe way to go, just $$$. The Sunsynk alternative offers good value - if it all works OK.
April 25, 20224 yr Author 13 hours ago, Scorp007 said: The 2.5-3 times current is related to the current the VFD can deliver to a load. Good to know, thanks Scorp007
April 25, 20224 yr 3 hours ago, Delta9 said: That's interesting - how do you find the Esybox? I have just bought an Esybox mini, a Dtron3 submersible and 4 x Esybox diver submersibles to try out. The Esybox Mini and the Esybox divers have a VFD onboard, the Dtron 3 has no VFD. I bought those 3 types of pumps from DAB to see what works well among them. I am also looking at Grundfos pumps because they have a nice VFD for thier pumps with some nice features, but that's the next experiment after the DAB's. All of these need to be run via an electrical inverter - either battery based or AC coupled hence asking this question. I know Victron is a safe way to go, just $$$. The Sunsynk alternative offers good value - if it all works OK. i love the Esybox. Had it for 18 months and pumped almost a million litres. Runs from my Sunsynk 8kw. No issues whatsoever
July 14, 20223 yr On 2022/04/24 at 4:56 PM, Delta9 said: Wondering if a HF Sunsynk can start a pump motor? Lets assume a 12kW 3Ph sunsynk and a 5.5kW 3 Ph motor started on a VFD. The sunsynk can surge to twice its load for 10s (or so says the manual). Start up load on a 5.5k 3 phase motor on a VFD should be limited to about 2.5 to 3 times the motor rating i think. Lets assume it spikes to 3 times - so thats about 17kW for a few seconds. I would have thought it would take 2 x 12kW 3Ph sunsynks in parallel to safely do this but i have no idea how HF inverters cope with starting motors. Then there is the added complication of not being to add a genset to a paralleled setup of sunsynks. maybe Victron is the way to go with its beefy toroidal transformer ? Two questions regarding use of VFDs with storage inverters: 1) Will harmonics reflected back to the source significantly distort the output voltage of the storage inverter? 2) Can the voltage distortion cause excessive heating and premature failure of internal storage inverter components?
July 14, 20223 yr 4 hours ago, Kilowatt Power said: Two questions regarding use of VFDs with storage inverters: 1) Will harmonics reflected back to the source significantly distort the output voltage of the storage inverter? 2) Can the voltage distortion cause excessive heating and premature failure of internal storage inverter components? Perhaps Goodling harmonics in inverters can lead you to some answers and mededies.
July 16, 20223 yr Just a question… when you drive a motor with vfd, the vfd is connected to a single phase usually… well my belt grinders are… so wouldnt your 5.5kW be over the 4kW of each phase in any case? I am not sure this is how a pump works, but my belt grinders do… so it is possible
July 17, 20223 yr 13 hours ago, Andre grobler said: Just a question… when you drive a motor with vfd, the vfd is connected to a single phase usually… well my belt grinders are… so wouldnt your 5.5kW be over the 4kW of each phase in any case? I am not sure this is how a pump works, but my belt grinders do… so it is possible You get VFDs that run off 3 phase.
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