All VFDs can convert single phase to 3 phase ???

Here is my story i live on a AG property and have 1ph 110-220 at my house .my 1.5 hp well pump recently failed and i decided to try my luck on ebay and see if i can get a good deal on a pump (because as a kid i watched too mutch ToolTime with Tim Allen I decided i need a 3hp or maybe a 5hp pump motor ,,so i bid on several listings on ebay and to my surprise won 2 auctions .. first pump has a 3ph fancy stainless German water cooled 2.4HP motor and other pump has a Nord 5 HP 3ph motor AND it also came with a 5hp rated VFD 3-phase input GS2-25P0 (GS2 series AC micro drive, 230 VAC, 5hp with 3-phase input, V/Hz mode, RS-232/RS-485, Modbus, 5kA SCCR).


My understanding the 5hp VFD is undersized for the 5hp motor, and in my case i would need a 10hp or a 15hp VFD to run that motor from 220 single ph.
and i have to buy the 208v-220v-230v input drive right? not the 380-480 volt input VFD if i want to run them from 1 phase.?

but no one sells 15hp single phase VFDs only the 3 phase input ones .

Can i use that 5hp VFD to run the 2.4HP Pump motor ???
VFD says its Input:200-240v 50/60hz 3-phase 19.6amps
But all i have available as Input is 110-120v or at max 200-240v 1-phase
Not Input:200-240v 50/60hz 3-phase ,how would that work. wires and ext. what goes were? i'm lost.

I fell like i am trying to screw a cow for the first time, and i don't know how to approach her step stool,flowers?
can i get some pointers here....

I just found out that VFD's exist only 2 days ago.
Madonna - Like A Virgin (video) - YouTube
I have bin digging the net tying to get proper info for 2 nights in a row now i need some sleep getting t0o koooky.

?not as important but : is there a physical difference in the VFDs for a Variable Torque and Constant Torque application or does that just depend ultimately on the vfd size % of max something something 120% vs 150% something surge or overload (don't know enough to finish this sentence)...


Be a good Samaritan, America needs you, protect your fellow citizens.... please help me so i can stop searching the web get some sleep and i need to drive a heavy sleepy truck tomorrow and i may live near you.

troll alert

3rd day I think I'm becoming colorblind looking at the screen fir too long still no help and no information online ....

Search this forum for "VFD"

You will be able to read such a wealth of knowledge as to make one's head spin in the riches.

Usual rules are derate the vfd by half if supplying it from single phase. however, that applies to real power delivered by the vfd to the motor, not reactive power.

You can run a 5 hp motor at 30hz at full nameplate torque from a 5 hp vfd run off single phase, but with a pump that only delivers a fourth of the pressure and is probably not an option.

you should be fine with a 5 hp vfd and a 2.4hp motor. keep in mind that if that's a "2.4KW" motor, then its actually 3.2HP. this is still within reason but you should find the optimal volts per hz to increase the efficiency of the motor, decrease the hz/rpm to reduce the motor load.

since you're upgrading from a 1.5hp to a much larger pump you should have plenty of margin to reduce the rpm to get the optimal efficiency (kilowatt hours per thousand gallons) while also reducing the load on the vfd.

AlexanderT said:

Here is my story i live on a AG property and have 1ph 110-220 at my house .my 1.5 hp well pump recently failed and i decided to try my luck on ebay and see if i can get a good deal on a pump (because as a kid i watched too mutch ToolTime with Tim Allen I decided i need a 3hp or maybe a 5hp pump motor ,,so i bid on several listings on ebay and to my surprise won 2 auctions .. first pump has a 3ph fancy stainless German water cooled 2.4HP motor and other pump has a Nord 5 HP 3ph motor AND it also came with a 5hp rated VFD 3-phase input GS2-25P0 (GS2 series AC micro drive, 230 VAC, 5hp with 3-phase input, V/Hz mode, RS-232/RS-485, Modbus, 5kA SCCR).


My understanding the 5hp VFD is undersized for the 5hp motor, and in my case i would need a 10hp or a 15hp VFD to run that motor from 220 single ph.
and i have to buy the 208v-220v-230v input drive right? not the 380-480 volt input VFD if i want to run them from 1 phase.?

but no one sells 15hp single phase VFDs only the 3 phase input ones .

Can i use that 5hp VFD to run the 2.4HP Pump motor ???
VFD says its Input:200-240v 50/60hz 3-phase 19.6amps
But all i have available as Input is 110-120v or at max 200-240v 1-phase
Not Input:200-240v 50/60hz 3-phase ,how would that work. wires and ext. what goes were? i'm lost.

I fell like i am trying to screw a cow for the first time, and i don't know how to approach her step stool,flowers?
can i get some pointers here....

I just found out that VFD's exist only 2 days ago.
Madonna - Like A Virgin (video) - YouTube
I have bin digging the net tying to get proper info for 2 nights in a row now i need some sleep getting t0o koooky.

?not as important but : is there a physical difference in the VFDs for a Variable Torque and Constant Torque application or does that just depend ultimately on the vfd size % of max something something 120% vs 150% something surge or overload (don't know enough to finish this sentence)...

View attachment 199720
Be a good Samaritan, America needs you, protect your fellow citizens.... please help me so i can stop searching the web get some sleep and i need to drive a heavy sleepy truck tomorrow and i may live near you.

Click to expand...

That's all very creative. Also stupid.

First thing you should do is go and get a downwell pump that fits the bore, is rated for the lift, and runs directly off the power you already have. Make sure you fit a snubber, else it will destroy wiring, pipe, or both.

That isn't near as hard as bathing off bottled water whilst taking six months to figure out you bought something off ebay that doesn't fit your circumstances in any case.

Deal with that.

Figure out how VFD work or how to please a cow as separate projects. Those don't go together, either.

Or so the grownups tell me, anyway. Never went onto MY dance-card.

I don't even date chubby HUMAN females, let alone ones with HAIR all over their body..

Monarchist said:

I don't even date chubby HUMAN females, let alone ones with HAIR all over their body..

Click to expand...

Not to side track from the intelligent subject matter, but one of the last times I visited a pipe supply warehouse one salesman brought out his smart phone and showed me pictures of the females on a dating website he uses. I was reminded of the times my father drove me thru the slum areas of town. Got home and appreciated what I little I had.

rons said:

Not to side track from the intelligent subject matter,

Click to expand...

LOL! Well... given where the OP STARTED, I thot we were ADDING to that part..



Mind there ARE a few VFD out there that might make servicing cows less odious than programming...

Hey johansen thanks for an adequate response..
Do you by any chance know what the difference between the inputs of a 3ph VLD and a 1ph?.

Yes i do not expect to run the larger pumps at full power all the time . My last pump was often ruining at max most summers because is was under powered the gpm output was to low for AG when needed . It burned out in 3 years the last one was same brand same size lived for about 4 years.

i would like the have the larger pump at max potential gpm curve for the 2.4hp pump that at about 2 hp( 40-50 hz probably,dont know?) and the 5hp motor is a positive displacement pump so its variable.

i would prefer to install the 5 hp and run it at about 2hp load and set it up to 3hp or more in the summer when i need it most.

if i pull to much juice from the VFD will it brake or will it just run under-powered? my understanding the vfd it will be destroyed.

Just wanted to clarify that I am not a crackhead gh i did look at my post after getting some sleep .i wasn't sleeping because i need water at my house asap im using a 110v 3/4 hp temporary pump that can fill a bath tub and flush toilets only.
My pump broke about 30 hours after that happened my wife went in to labor, Murphy's law, i need to learn everything i can ,everything that i need to know about 3ph and VFDs and install the pump asap.
The reason i got in to the larger pumps is they are the smallest industrial grade high quality German stainless internals and are reparable pumps i could find for reasonable price.
,unlike the Granger overpriced not serviceable made in india plastic internal pumps i was using.
i spend $2500 on replacing same pump twice in last 6 years ,the old pumps are sealed and not reparable . i may be in a pinch but i'm not going to make the same mistake 3 times. (that would be stupid).
As soon as they arrive from shipping ( in a few days from now ) i need to be ready to install asap properly . I already ran 4# wire to pump house with 100 amp barker just in case.. i had the wire in the barn has been there from the 90s and amps to spear,,why not. ill prepare the new plumbing tomorrow.

What i don't have is enough knowledge about 3 ph and VFD and hope someone here will help me out and clarify my concerns. i dont want to make some stupid rookie mistake and fry the VFD,,ext .
I just don't have the time or money to learn from my mistakes at this time.

There is a guy locally that has a 40 hp delta vfd for sale for $350 as is ,but he does't know were its form and how old it is ,he got it from those storage auctions.
can i use it to run the 5hp from 1 220 ph? will i need to run larger wires for input if i plan to use only 5 hp as output not more ( 40hp needs i think 150 amps of 1 220 ph.)

Should i buy the 40hp vfd??? my understanding VFDs can go bad ,or at-least the capacitor do ,,and then what ?? buy new caps and solder??

Search the forum for, reforming capacitors. Before you power up any used drive.

SAF Ω

A 3ph VFD allows the DC bus capacitor to have three charging paths. The VFD may allow allow you to connect single phase input but the motor HP will have to be reduced. The reason is that the number of charge paths are reduced and the DC bus capacitor(s) are not receiving as many current pulses per second. The output is rated below what the 3 ph hp number is. For example a 5hp 3ph number would become 3hp at 1 ph. The manual will explain what the numbers are. It's as simple as that.

The pump motor Hp determines what you need. You can use a 5 Hp VFD to run a 2.4Hp motor if your input was 3ph. For single phase I suspect it would be fine, but always check what the derating factor is as mentioned above.

If you know what VFD's you are thinking about then specify. Someone could look up the answers for you if you are getting lost. Then soon you will see what all this means.

hay thanx (current pulses per second-i think i just got it)

so the 3 phase VFD,,, is each leg of 3ph connected to caps separately or are the caps bridged together?
they are probably bridged.??? correct me if i am wrong please.

if thay are would mean all the VFD input connections internally are the same ether the single ph or the three ph. (are they??)

the only difference in capacitors with different amp speed ratings.
like the 220 rated caps are faster then the 230 and the 230s are faster then the 460v and so on...

DC bus capacitor to have three charging paths capacitor(s) they don't receive as many current pulses per second in single phase
(that makes sense)
so to run in single phase you need caps that except higher amps, right?
so technically single phase vfd needs super caps or just faster caps on the VFD to work properly with correct Vfd hp rating.
that's the reason you must use a bigger hp VFD with single phase although you dont need that much stored 'power' on the larger caps intended for higher hp motors
you do need them to except higher amps intended for higher hp draw.

And if you use VFD Input Voltage if 460 VAC it can run from a 220 single phase but it needs to be rated for higher hp then lets say 220 vac or same amperage ?


so i did dome research. now that i knew what to look for.

So the 3hp 1-phase 220 vac VFD input Amperage Rating is 10 amps
3hp with 3-phase input 460 VAC is 5 amps
5hp with 3-phase input 460 VAC is 8.3 amps
7-1/2hp 3-phase input 460 VAC is 13 amps



This is what im going to be revising on Wednesday

first pump) 5 hp nema 3.7kw 208-230/460 motor and (automationdirect vdf

GS2-25P0 (GS2 series AC micro drive, 230 VAC, 5hp with 3-phase input, V/Hz mode, RS-232/RS-485, Modbus, 5kA SCCR).


second pump) 2.4hp (dw 80-70 DIETZ) 230v 6.5amp 1.8kw
Liquid cooled motors Prufstandsmotoren Axialmotoren Drehstrommotoren Elektromotoren Industrievewntilatoren Synchronmotoren Wechselstrommotoren

i know know i cant use the VFD with the 5hp motor firstly three is little leeway for current draw for jump start 5 hp right?
secondly its not realistic using 1 phase just not enough amps.

so it looks like were amps are condensed i will be able to use the 5hp 8.3 amp VFD on the 6.5amp 2.4hp motor in single phase

(so is that the only factor that rates the VFDs ??)current pulses per second
amp draw capacity ?

or are there physical differences?
caps bridged together on one phase VFD and separate on 3 phase?


how can i find the derating factor ?? am i looking for amps or something else?


also what will happen if i run the 5 hp motor with the 5 ph 3ph VFD on 1 phase 220

can i just set the VFD to startup at 5 amps or 50% power of motor? will it just drive output in lower current or will the VSD be destroyed some how it cant pull as much as it needs ??

RONS do reply's not show up on forum thread ? i just spend about an hour typing and it dint show up..im new at this too ,if not can you repost what i wrote you in the reply in the thread please .

current pulses per second that makes seance .

so are amps input is the only factor? speed of caps??

so 220v caps are faster draw then the 460v caps and to run 1 ph from 460v caps they need to have higher amp rating witch would usually rate them for higher HP rating in 3 ph applications ?

are caps bridged for single phase input VFD's?
are caps bridged for 3 phase input VFD's?

theoretically
if i use a vfd 3 phase in with Amperage Rating of 10 Amps on a 3 phase motor Amperage Rating 10 amps or 30 amps in single phase but i set the vfd to 33.3% output max 10 amps max will the VFD work or will the VFD get destroyed
wouldn't the drive output just fine at a lower current running the motor at 1/3 power or will the caps or something blow ??
seams that nothing would brake in the VFD if there is not enough power it just will not push the output if its underpopulated.
what can happen??
theoretically
it seams more dangerous to set a 40 hp VFD on a 10 hp motor and then accidentally run it on 40 hp. then set a 10 hp VFD to run at max on a 40 hp motor..
DC bus capacitor(s) are not receiving as many current pulses per second, was a simpler explanation
now im just confused

(The important bit is that the output voltage is always the same or less than the input voltage)

so your saying 460v output and 220v in is a no no?
then whats the point if a vfd besides the soft start and reverses ext.

i have

input 220 vac 1 phase


GS2 series AC micro drive, 230 VAC, 5hp with 3-phase input, V/Hz mode, RS-232/RS-485, Modbus, 5kA SCCR.
VFD Output Voltage 230 VAC
Voltage Type AC
Nominal Input Voltage 230 VAC
Nominal Output Voltage 230 VAC
Number of Phases 3-phase
Horsepower By Phase 5hp with 3-phase input
Amperage Rating 17A

according to AC Motor Full Load Amperes
AC Motor Full Load Amperes | Applied Industrial Controls

first pump 2.4hp 3ph 230 volts 6.5A 1.8 kw. so (about 15 amps in 220v)
i have about 2 amps to spare

second pump 5hp 3ph 230/460 15.2-7.6A 3.7kw so thats( 28 amps in 220v)

so can i run the 5 hp motor without damaging the VFD
can i run the 5 hp motor at 3 hp witch would be 17 amps without damaging the VFD.

In case you need simpler explanations: all VFDs take whatever the input is (single or three phase) and rectify it to DC. Form there some tricky electronics convert the DC to 3-phase with variable frequency (and clever tricks like gentle start-up, braking, motor protection etc).
The important bit is that the output voltage is always the same or less than the input voltage (one exception available form England).
So your motors (pumps) MUST be able to be configured to the voltage you have available (single or 3-phase, 120, 240, 380, 415 - whatever). Secondly, the VFD MUST be designed for that voltage too.
If not, you are up the creek without a paddle.
If they all match, then you can start reading the manual and learn about settings, derating for certain inputs and conditions etc.
Some of the information for the last bit is already here above.

DC bus capacitor(s) are not receiving as many current pulses per second, was a simpler explanation
now im just confused

(The important bit is that the output voltage is always the same or less than the input voltage)

so your saying 460v output and 220v in is a no no?
then whats the point if a vfd besides the soft start and reverses ext.

i have

input 220 vac 1 phase


GS2 series AC micro drive, 230 VAC, 5hp with 3-phase input, V/Hz mode, RS-232/RS-485, Modbus, 5kA SCCR.
VFD Output Voltage 230 VAC
Voltage Type AC
Nominal Input Voltage 230 VAC
Nominal Output Voltage 230 VAC
Number of Phases 3-phase
Horsepower By Phase 5hp with 3-phase input
Amperage Rating 17A

according to AC Motor Full Load Amperes
AC Motor Full Load Amperes | Applied Industrial Controls

first pump 2.4hp 3ph 230 volts 6.5A 1.8 kw. so (about 15 amps in 220v)
i have about 2 amps to spare

second pump 5hp 3ph 230/460 15.2-7.6A 3.7kw so thats( 28 amps in 220v)

so can i run the 5 hp motor without damaging the VFD
can i run the 5 hp motor at 3 hp witch would be 17 amps without damaging the VFD.

The 5hp class VFD is specified for 3 phase input. If you use 230v single phase input the hp rating will not be 5hp. I'm not sure what you could get, may be 3hp. Therefore you would have to go with the 7.5 or 10 hp class units. The 3hp class unit will accept 230v single phase.

https://cdn.automationdirect.com/static/specs/gs2drive.pdf

If I were you, a guy who depends on a water supply via VFD, I would become a VFD expert. I would also become an expert on what a pump is and the max and min loads that occur, etc.

If you buy a 3hp pump then get the 3hp class VFD that accepts 230V single phase. Since the original pump was 1.5Hp then you have the job done.

If you need 5hp then you need to be sure that the input of 230V single phase will be acceptable. As I see the data, your choice of the 5Hp class VFD will not allow you 5Hp at the output with 230V single phase input.

There is way too much superfluous stuff here to read it all, so I'll try to address your issues as I saw them in the beginning.

1) CAN any VFD convert single phase to 3 phase? Yes, technically. WILL all of them do it? No, for a host of different reasons, SOME mfrs don't allow it. Bottom line if you want to do it, ALWAYS ask if it is possible before buying. IF you are going to do this, then the VFD must be sized at LEAST 2x the motor rating, preferably by amps, not HP, because HP is a nebulous thing sometimes. The reason is, the VFD must convert (rectify) the incoming AC power to DC, then reconvert (invert) the DC back into something the motor thinks is AC. In that process, the DC bus must use capacitors to smooth out the ripple effect of the rectification process and if feeding a VFD with single phase, that rectification causes MUCH more ripple in the DC bus, so you need more capacitance. Doubling the size of the drive ensures that you get enough. that said, on 230V drives at 3HP and under, the capacitors used by most VFD mfrs are sized for this duty whether you need it or not, because at that size, the caps are cheap anyway. So you will see a lot of VFDs at 3Hp and under that say you can feed them with single or 3 phase and no de-rating is necessary. there are a few people selling some that claim 5HP single phase w/o de-rate, but in reality they are just doing the de-rate for you and selling you a 10HP VFD, which you can figure out by just comparing their pricing. For the most part if you find a 230V VFD that is OK with being fed single phase, if you motor is 5HP or larger, you must double the size of the VFD at a MINIMUM (some are going to say 65% de-rate or de-rate the ambient temperature to 25C which is damned near impossible).


2) What voltage to use? The voltage of your motor and supply must be the same in most cases. So if you have a 230V motor, you must have 230V available, whether it's single phase or 3 phase. A standard VFD cannot create voltage that is not there. The ONE exception to this is that there are some SMALL VFDs on the market that have a special design called a "Voltage Doubler" on the front end that allows you to put 115V single phase in and get 230V 3 phase out of it. This technology is limited to around 1HP at 230V, beyond that and the components that do the work get too hot and too expensive, compared to just buying a transformer that will take 115V in and give you 230V out. If you buy a 380-480V rated VFD, it will not work on 230V, so forget those. By the way, I use the nominal value of 230V because that is the standard in place NOW, but 220V, 240V etc., it's all the same thing. 240V +-5% is what the utility delivers, 230V +-10% is what the motors are made for (expecting some voltage drop), 220V is an old standard that still shows on older equipment.

3) Constant vs Variable Torque? This is a marketing issue; "Variable Torque" refers to the type of MACHINE you connect the motor to, i.e. centrifugal pumps and fans are "variable torque" machines. That means as the speed decreases, the power needed by the pump decreases at the CUBE of the speed change, so for example at 50% speed, the power demanded from the motor by the pump is .5 x .5 x .5 so .125 of the power required at full speed. From the VFD standpoint, that means the power devices cannot be overloaded when speed is reduced, so the components can be de-rated at a higher current output. So a 50HP rated VFD can handle a 60HP Variable Torque load. Once you get to 10HP and below, the VFD mfrs no longer play this game, so it's a moot point. But if buying a VFD that is 2x the size of the motor because you are feeding it with single phase, then it might make a difference, and so YES, if using this to power a pump, then you could use a VT rated drive (that is 2X the motor). Anything other than a centrifugal pump or fan is a Constant Torque load and you can't play any numbers games.

4) Can I run a bigger motor at reduced power? Technically, yes, IF you know what you are doing, but it's not something I would recommend to a rookie. You CAN indeed damage the VFD if you don't set it up correctly. But to elaborate, what you must do is set up a "Current Limit" in the VFD to the maximum safe load it can handle, then live with the consequences of what that means. So in the case of your 5HP motor and 5HP drive, you CAN program that drive for a Current Limit of 50% of the 17A rating, so call it 9A. What that will mean is that the motor will ramp the speed up, UNTIL it hits 9A, then is will CEASE to increase the speed, because speed = load. Now, what speed will that be" it's really difficult to tell, especially on a well pump, because the current = torque, and the torque relates to not only the flow, but also the "head pressure", the weight of the column of ware that the pump must lift BEFORE anything can start flowing. So in your well, you might end up with most of your available torque being consumed by the well head, so when the water gets to the to, the drive is out of juice to make pressure and you end up needing 2 hours to get the shampoo out of your hair in the morning. But really, it boils down to what you need. IF you have already been told that a 2.4HP pump will give you what you need, then chances are that a current limited 5HP pump will likely do it too. I wouldn't do it that way because a 5HP pump would likely cost ore, but I don't know your circumstances.

There are legit VFDs that are single phase rated. They are simply made with larger caps and rectifier. I suppose that could be said to be "really just a derated VFD of double power", except for the output IGBTs.

I would call it a single phase input rated VFD, but then, I originally come from the single phase power electronics world, audio amplifiers, analog and class-D, up to something over 3HP of output. Those parts seem normal to me, and the ability to get by with a 50uF film cap as the main filter for a several HP VFD design was "interesting" the first time I did it.

The problem with a 3phase VFD on single phase is not so much that it will not put out full power, but rather that it WILL TRY TO. It will simply do what is asked, to the best of its ability, assuming it has no ripple detector, etc.

That will likely exceed rectifier limits, overheating the rectifiers and causing failure... Or the excess ripple current will overheat and cause failure of the filter capacitors.

Many will fault out on excess ripple voltage, or on undervoltage of the DC bus, if asked to put out full power on single phase. You would need to. know some design details to know exactly what the unit COULD, or would, actually put out at maximum on single phase.

With very current design strategies, YOU CAN NOT BE SURE OF THE 50% DERATE number. It may be that even more derate is required.

Consult the mænual. If derated operation is applicable, there should be a number given.

Jraef said:

4) Can I run a bigger motor at reduced power? Technically, yes, IF you know what you are doing, but it's not something I would recommend to a rookie. You CAN indeed damage the VFD if you don't set it up correctly. But to elaborate, what you must do is set up a "Current Limit" in the VFD to the maximum safe load it can handle, then live with the consequences of what that means. So in the case of your 5HP motor and 5HP drive, you CAN program that drive for a Current Limit of 50% of the 17A rating, so call it 9A. What that will mean is that the motor will ramp the speed up, UNTIL it hits 9A, then is will CEASE to increase the speed, because speed = load. Now, what speed will that be" it's really difficult to tell, especially on a well pump, because the current = torque, and the torque relates to not only the flow, but also the "head pressure", the weight of the column of ware that the pump must lift BEFORE anything can start flowing. So in your well, you might end up with most of your available torque being consumed by the well head, so when the water gets to the to, the drive is out of juice to make pressure and you end up needing 2 hours to get the shampoo out of your hair in the morning. But really, it boils down to what you need. IF you have already been told that a 2.4HP pump will give you what you need, then chances are that a current limited 5HP pump will likely do it too. I wouldn't do it that way because a 5HP pump would likely cost ore, but I don't know your circumstances.

Click to expand...

this is a good explanation but it is incorrect in one regard:

there is no current limitation for the output of the drive regarding single phase derating; there is a power limitation, because all we care about is the rms amps going into the capacitors through the diodes that are dammed near asked for triple duty (double the rms amps through 2/3rds of the diodes, (yeah, i know, its more complicated). if we care about the rms amps demanded by the igbt block then we also have to make a more careful look at the situation, but a thermometer on the capacitors might be more practical.

in the case of a well pump he might be ok driving a 5 hp motor from a 5 hp vfd on single phase up until 80% of 60hz. 80%^3 is 1/2.. if the static head pressure isn't significant.

if the percentage of static head pressure to flow rate losses is high then an additional derating will be required.

worst case is a positive displacement pump, in such a case running the motor at nominal nameplate volts per hz, at 30hz is safe for a nominally rated VFD run from single phase, as i said in my prior post.