Re: [RE-wrenches] Autotransformer for Single Phase Motor Headache
Hi Chris, In the past, I was able to start a 5 hp pump motor using a VFD. , I can not remember the make, of the VFD but I think it was an ABB 7.5 or 10 HP connected to a single-phase motor. I started it on two Outback 3548s (or maybe 3024s). Now for the tricky part, I have done this several times over the years so I keep confusing the systems. you must power the VFD before starting the motor to charge the capacitors as the VFD will also have a loading surge.( one time on maybe 10 HP I did a homemade resistor) The VFD has a large capacitance and will have a surge. Most water pumps do not have a high zero-speed torque requirement, meaning low inertia, so you can use a slower ramp to speed. watch your speed as the VFD can Overspeed the motor increasing the load. The advantage of the VFD is it can run at a lower speed reducing the load on the inverter. I also think an Auto Transformer will balance the load between the inverters, but may not be necessary. Also be aware that starting surge is on the battery also, If your motor has aGH motor it can have a 4 to7 times the running loads on starting. NEC 430,7 I think. This can be well over 100 amps. The inverter will sag in voltage during startup but they may draw 400 or 500 amps from the battery. If my memory is correct the 10 HP VFD has the possibility of adding an extra capacitor which reduces AC starting draw. Sorry, this was so long, it was more than 20 years ago for me. On Fri, Jan 28, 2022 at 10:46 AM Chris Sparadeo wrote: > Hi all, > > I currently have an off-grid client that has a 120/240VAC 7.5 HP - 40A > FLC single phase pool pump. Locked rotor current is around 110 A. I had > initially (and naively) thought that two Sol Ark 12k units would be able to > handle this load. Due to the lack of a transformer, the unit's just can't > output the required inductive startup inrush. Now getting clarification > from Sol Ark that max inductive HP output is 2.5 HP per unit. We had > installed an amply sized SR35 soft starter, with no avail. The 20 kW > generator can start the motor, but it is noticeably shaken with the > intense load drop. > > I am toying with the idea of installing a VFD and upgrading the pool pump > to a three phase motor. Would make for a much smoother ramp and self start. > The client is a bit hesitant to upgrade and would like to continue using > their clunky, non-self starting single phase motor. > > My other thought was to implement an autotransformer to add some copper to > the equation and help the Sol Ark's get the job done. Has anyone had any > experience with the Victron 100A autotransformer for both 120/240 input and > output? > > Any suggestions or relative experience would be greatly appreciated! > > -Kindly, > > -Chris > > -- > > *Chris Sparadeo * > > *NABCEP Certified PV Installation Professional **® **# 042919-015652* > > *NABCEP Certified PV System Inspector **®** # 052920-015652 * > > *State of Vermont Journeyman Electrician # EJ-07619* > ___ > List sponsored by Redwood Alliance > > Pay optional member dues here: http://re-wrenches.org > > List Address: RE-wrenches@lists.re-wrenches.org > > Change listserver email address & settings: > http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org > > There are two list archives for searching. When one doesn't work, try the > other: > https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/ > http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org > > List rules & etiquette: > http://www.re-wrenches.org/etiquette.htm > > Check out or update participant bios: > http://www.members.re-wrenches.org > > ___ List sponsored by Redwood Alliance Pay optional member dues here: http://re-wrenches.org List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org There are two list archives for searching. When one doesn't work, try the other: https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/ http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: http://www.re-wrenches.org/etiquette.htm Check out or update participant bios: http://www.members.re-wrenches.org
Re: [RE-wrenches] Autotransformer for Single Phase Motor Headache
Hi Chris I googled and a new 3phase motor is about $1000 and the vfd is about $500 maybe. Say $3000 for the upgrade? Seems like the easiest to do, easier on the existing inverters, it’s the least expensive long term option. I don’t know what the transformer would provide as a fix because the pump is already 240? I’m not even going to ask if he actually needs a 7.5hp motor. Jay > On Jan 28, 2022, at 9:46 AM, Chris Sparadeo wrote: > > > Hi all, > > I currently have an off-grid client that has a 120/240VAC 7.5 HP - 40A FLC > single phase pool pump. Locked rotor current is around 110 A. I had initially > (and naively) thought that two Sol Ark 12k units would be able to handle this > load. Due to the lack of a transformer, the unit's just can't output the > required inductive startup inrush. Now getting clarification from Sol Ark > that max inductive HP output is 2.5 HP per unit. We had installed an amply > sized SR35 soft starter, with no avail. The 20 kW generator can start the > motor, but it is noticeably shaken with the intense load drop. > > I am toying with the idea of installing a VFD and upgrading the pool pump to > a three phase motor. Would make for a much smoother ramp and self start. The > client is a bit hesitant to upgrade and would like to continue using their > clunky, non-self starting single phase motor. > > My other thought was to implement an autotransformer to add some copper to > the equation and help the Sol Ark's get the job done. Has anyone had any > experience with the Victron 100A autotransformer for both 120/240 input and > output? > > Any suggestions or relative experience would be greatly appreciated! > > -Kindly, > > -Chris > > -- > Chris Sparadeo > NABCEP Certified PV Installation Professional ® # 042919-015652 > NABCEP Certified PV System Inspector ® # 052920-015652 > State of Vermont Journeyman Electrician # EJ-07619 > ___ > List sponsored by Redwood Alliance > > Pay optional member dues here: http://re-wrenches.org > > List Address: RE-wrenches@lists.re-wrenches.org > > Change listserver email address & settings: > http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org > > There are two list archives for searching. When one doesn't work, try the > other: > https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/ > http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org > > List rules & etiquette: > http://www.re-wrenches.org/etiquette.htm > > Check out or update participant bios: > http://www.members.re-wrenches.org > ___ List sponsored by Redwood Alliance Pay optional member dues here: http://re-wrenches.org List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org There are two list archives for searching. When one doesn't work, try the other: https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/ http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: http://www.re-wrenches.org/etiquette.htm Check out or update participant bios: http://www.members.re-wrenches.org
Re: [RE-wrenches] Well siphon?
Great Explanation Jay. One can just feel those molecules being pulled apart to gas! One could however recover the energy needed for pumping over the hump with a small turbine on the down side but probably not worth the expense and complexity. Sent from my iPhone > On Jan 28, 2022, at 9:46 AM, Jay wrote: > > > Hi Bill > > Ok I’ll trybto explain 1 more time. > Let’s take your example. > Lake level at 100’, top of dam at 143’ output of the pipe at 0’ > The pipe is sch 80 steel,totally filled with water, no air. There is a check > valve at the lake side which will allow lake water in but not out, with the > pipe intake below water level, and there is a valve at the other end. > > When you open the valve at the bottom, that 143’ of water will start to move > out of the bottom of the pipe. It will be pulling up on the 43’ from the top > of dam down to the water. 33’ down from the dam top on the lake side it will > turn to vacuum leaving 10’ of water in the pipe. The other 33’ above it will > siphon over the top of the dam and slowly make its way down the pipe. > > It cannot pull more than 33’ at sea level. Just the way it is. > > You can find good YouTube videos of water “boiling”at room temperature under > a vacuum, and that’s what happens in that pipe. That boiling means that the > water is no longer a liquid but a gas. > > Jay > > > >>> On Jan 27, 2022, at 8:09 PM, frenergy wrote: >>> >> >> This is good, I'm not yet willing to accept egg-defeat. In my previously >> described scenario, the atmospheric pressure does not play a role because >> I'm not evacuating the air-filled pipe with the suction side of a pump which >> would rely on atmospheric pressure to fill the pipe with water as the vacuum >> increases inside the pipe. >> >> In my scenario the pipe going over the ridge is filled with >> water from the discharge side of a pump, it could be filled from anywhere in >> the pipe but there must be an exhaust only air vent at the highest point of >> the pipe. Both ends of the pipe must not allow any air in and one end of >> the pipe must be lower than the other. Because we are not dealing with a >> mere 1 atmosphere of pressure (or vacuum in this case), the "pull" of the >> water on the lower side of this pipe will cause tremendous crushing pressure >> on the outside of this pipe that's drawing out of the well. I think the >> physics is right but I'm not sure how practical it is. The pipe has to be >> absolutely air-tight, completely full of water and extremely strong. >> >> Now I'm really sticking my neck out. There's gotta be an old >> physics teacher out therehelp! >> >> Bill >> >>> On 1/27/2022 6:14 PM, Jay wrote: >>> Hi Bill >>> >>> Sorry about the egg >>> >>> Here is some actual info to confirm what I and others have said. >>> >>> You cannot vacuum water any more than 33’ at sea level. >>> >>> >>> >>> https://www.nwcg.gov/course/ffm/squirt-water/35-drafting-guidelines >>> >>> Jay >>> On Jan 27, 2022, at 5:34 PM, frenergy wrote: OK, I'll gamble some egg on my face. In this case though, you would not be "pulling a vacuum" with air (a gas) involved. If you can fill the entire pipe with a liquid (water), the water that's down slope of the water in the well on the other side of the ridge it would pull the water out of the well and up over that ridge as long as the pipe exit is below the dynamic water level in the well and the pipe's intake. The caveat: the pipe would have to be filled by pumping out of the well (one time to set-up this siphon) and the exit end of the pipe would have to be closed to be able to fill the pipe completely, which would require an air vent (exhaust vent only, not intake) at the highest point of the pipe going over the ridge. A valve would also be required at the exit end for flow control and prevent the siphon from drawing the well dry. The pipe would have to rated to handle the crushing force of the vacuum being pulled on the uphill section of pipe after it left the well. There could absolutely not be any leaks in the pipe. I hope my seat-of-the-pants physics is working today. Bill Feather River Solar Electric Bill Battagin, Owner 4291 Nelson St. Taylorsville, CA 95983 530.284.7849 CA Lic 874049 On 1/27/2022 2:28 PM, Darryl Thayer wrote: > Yes, but if the rise is greater than about 30 feet (25 feet even) the > water head is greater than atmospheric and the water will draw a vacuum > in the pipe. These numbers depend upon the location (elevation) and > temperature of the water. > for example at 15,000 feet the atmosphere is about 1/2 or sea level, > meaning the water column will break at 15 feet of head. (from my h
Re: [RE-wrenches] Well siphon?
Hi Bill Ok I’ll trybto explain 1 more time. Let’s take your example. Lake level at 100’, top of dam at 143’ output of the pipe at 0’ The pipe is sch 80 steel,totally filled with water, no air. There is a check valve at the lake side which will allow lake water in but not out, with the pipe intake below water level, and there is a valve at the other end. When you open the valve at the bottom, that 143’ of water will start to move out of the bottom of the pipe. It will be pulling up on the 43’ from the top of dam down to the water. 33’ down from the dam top on the lake side it will turn to vacuum leaving 10’ of water in the pipe. The other 33’ above it will siphon over the top of the dam and slowly make its way down the pipe. It cannot pull more than 33’ at sea level. Just the way it is. You can find good YouTube videos of water “boiling”at room temperature under a vacuum, and that’s what happens in that pipe. That boiling means that the water is no longer a liquid but a gas. Jay > On Jan 27, 2022, at 8:09 PM, frenergy wrote: > > > This is good, I'm not yet willing to accept egg-defeat. In my previously > described scenario, the atmospheric pressure does not play a role because I'm > not evacuating the air-filled pipe with the suction side of a pump which > would rely on atmospheric pressure to fill the pipe with water as the vacuum > increases inside the pipe. > > In my scenario the pipe going over the ridge is filled with water > from the discharge side of a pump, it could be filled from anywhere in the > pipe but there must be an exhaust only air vent at the highest point of the > pipe. Both ends of the pipe must not allow any air in and one end of the > pipe must be lower than the other. Because we are not dealing with a mere 1 > atmosphere of pressure (or vacuum in this case), the "pull" of the water on > the lower side of this pipe will cause tremendous crushing pressure on the > outside of this pipe that's drawing out of the well. I think the physics is > right but I'm not sure how practical it is. The pipe has to be absolutely > air-tight, completely full of water and extremely strong. > > Now I'm really sticking my neck out. There's gotta be an old > physics teacher out therehelp! > > Bill > >> On 1/27/2022 6:14 PM, Jay wrote: >> Hi Bill >> >> Sorry about the egg >> >> Here is some actual info to confirm what I and others have said. >> >> You cannot vacuum water any more than 33’ at sea level. >> >> >> >> https://www.nwcg.gov/course/ffm/squirt-water/35-drafting-guidelines >> >> Jay >> >>> On Jan 27, 2022, at 5:34 PM, frenergy wrote: >>> >>> >>> OK, I'll gamble some egg on my face. In this case though, you would not be >>> "pulling a vacuum" with air (a gas) involved. If you can fill the entire >>> pipe with a liquid (water), the water that's down slope of the water in the >>> well on the other side of the ridge it would pull the water out of the well >>> and up over that ridge as long as the pipe exit is below the dynamic water >>> level in the well and the pipe's intake. >>> >>> The caveat: the pipe would have to be filled by pumping out of >>> the well (one time to set-up this siphon) and the exit end of the pipe >>> would have to be closed to be able to fill the pipe completely, which would >>> require an air vent (exhaust vent only, not intake) at the highest point of >>> the pipe going over the ridge. A valve would also be required at the exit >>> end for flow control and prevent the siphon from drawing the well dry. The >>> pipe would have to rated to handle the crushing force of the vacuum being >>> pulled on the uphill section of pipe after it left the well. There could >>> absolutely not be any leaks in the pipe. >>> >>> I hope my seat-of-the-pants physics is working today. >>> >>> Bill >>> >>> Feather River Solar Electric >>> Bill Battagin, Owner >>> 4291 Nelson St. >>> Taylorsville, CA 95983 >>> 530.284.7849 >>> CA Lic 874049 >>> >>> >>> >>> >>> On 1/27/2022 2:28 PM, Darryl Thayer wrote: Yes, but if the rise is greater than about 30 feet (25 feet even) the water head is greater than atmospheric and the water will draw a vacuum in the pipe. These numbers depend upon the location (elevation) and temperature of the water. for example at 15,000 feet the atmosphere is about 1/2 or sea level, meaning the water column will break at 15 feet of head. (from my high school physics, this is the scale height) so that at 7500 feet the water column is a maximum of 3/4 x 30 feet or 22 feet. this is from memory and mine is not so good. On Thu, Jan 27, 2022 at 3:51 PM William Miller wrote: > Colleagues: > > > > All of our water pumping customers to date have been pumping water to > tanks higher in elevation than the well-head. Just now I am looking
[RE-wrenches] Autotransformer for Single Phase Motor Headache
Hi all, I currently have an off-grid client that has a 120/240VAC 7.5 HP - 40A FLC single phase pool pump. Locked rotor current is around 110 A. I had initially (and naively) thought that two Sol Ark 12k units would be able to handle this load. Due to the lack of a transformer, the unit's just can't output the required inductive startup inrush. Now getting clarification from Sol Ark that max inductive HP output is 2.5 HP per unit. We had installed an amply sized SR35 soft starter, with no avail. The 20 kW generator can start the motor, but it is noticeably shaken with the intense load drop. I am toying with the idea of installing a VFD and upgrading the pool pump to a three phase motor. Would make for a much smoother ramp and self start. The client is a bit hesitant to upgrade and would like to continue using their clunky, non-self starting single phase motor. My other thought was to implement an autotransformer to add some copper to the equation and help the Sol Ark's get the job done. Has anyone had any experience with the Victron 100A autotransformer for both 120/240 input and output? Any suggestions or relative experience would be greatly appreciated! -Kindly, -Chris -- *Chris Sparadeo * *NABCEP Certified PV Installation Professional **® **# 042919-015652* *NABCEP Certified PV System Inspector **®** # 052920-015652 * *State of Vermont Journeyman Electrician # EJ-07619* ___ List sponsored by Redwood Alliance Pay optional member dues here: http://re-wrenches.org List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org There are two list archives for searching. When one doesn't work, try the other: https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/ http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: http://www.re-wrenches.org/etiquette.htm Check out or update participant bios: http://www.members.re-wrenches.org
