# VFD seems too good to be true



## andrewgr (Dec 13, 2020)

I don't know much about electronics or motors, so I assume that I am misunderstanding what this product does.  https://www.amazon.com/Huanyang-Variable-Frequenc-Controller-Inverter/dp/B07GD628D7

I am interpreting this description to say that it takes standard household 1 phase 110v input, and puts out 3 phase 220v output.  The description does not specify the output amperage, but the seller says in the Q & A section that it is 20 Amps.

That seems too good to be true, so I assume I'm just misunderstanding?  I mean, if that's right, I'll be placing an order for a 3-phase Precision Matthews Lathe and Mill tomorrow. 

Thanks in advance for any help.


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## Cooter Brown (Dec 13, 2020)

Yes, that is exactly how it works...... 1ph 110v in 3ph 220v out...... or 3ph 220 in 3ph 480 out.... VFDs are like magic.....


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## Lo-Fi (Dec 13, 2020)

It does state that it's a "rising voltage" model, so I assume it has a transformer or buck internally to bump the internal rails up enough for 220v output. If you want a three phase tool but only have a 110v supply in your shop (I'm assuming), this seems like a good option. Nice thing about the VFD here is soft start, which means you won't get crazy current demands the moment the motor starts.


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## cathead (Dec 13, 2020)

You would have double the energy available if you could input a VFD with 220 volt power.  It is a severe
limitation if you use 110 power.  If in the future you want more power, you won't have that option if using
110V.


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## Karl_T (Dec 13, 2020)

This is the first VFD I've seen going up to 3 Hp on 110...  1 Hp. units are common and proven.

1 Hp. yep, go 110,  myself I would not be the first to try this.  I suppose if there is NO WAY you can find a 220 source, maybe. Don't be surprised when issues pop up.


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## Cooter Brown (Dec 13, 2020)

Oooooh yeah, Dont run a VFD inline with a GFI you will never get you motor started.....lol


Dont ask me how I know......


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## sdelivery (Dec 13, 2020)

I dont believe I have ever seen a 110V single phase VFD rated for 3 HP.
There rated to 1 HP generally and dont even do that well.
If you dont have 220 V where you are going to put the machine rethink your strategy


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## John O (Dec 13, 2020)

Isn't 2.2 Kw at 220 V 10 A


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## mksj (Dec 13, 2020)

A standard 3 Hp 220/240V input VFD specifies a 30A breaker, so at 110/120V you are looking at 50-60A breaker. VFD's can put out up to 180-200% of their rated output for up to 1 minute, and the current draw is in pulses so the spikes/peaks are extremely high in single phase. This would also be worse at 120VAC and I would want to see the electrical noise that one would be generating. So I would not expect that you can run this off of a 20A 120VAC plug. Hp is Hp, their is a reason why the largest 120V motors that can plug into a 20A socket is around 1.5Hp. I have also indicated in other postings that a 20A breaker/circuit cannot deliver 20A continuously, they are only designed to provide 80% amperage continuously so puts you at 16A.  No free lunch on this one.


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## markba633csi (Dec 13, 2020)

20 amp input I'm sure, not output.  No way can you run 3hp on 110v household circuit
-Mark


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## kb58 (Dec 13, 2020)

It seems VFDs are going down the same marketing slope as air compressors and vacuum cleaners, all claiming big power.

As was said, hp is hp. One horsepower is 746 watts no matter how it's delivered. The OP says the VFD is running on 110V, so that means a perfectly efficient product would consume an average of 746 / 110 = 6.8 amps for every hp delivered. But nothing is 100% efficient; it's maybe 90% (for a really efficient unit), so that 6.8 amps ends up being 6.8 / 0.90 = 7.5 amps per hp. Since the mfg is claiming 3 hp output, it means that at least 3 * 7.5 = 22.5 amps is being drawn from the 110V outlet. AFAIK, no homes are wired to handle that.

MKSJ is right, a real 3hp VFD uses a 30 amp breaker when run on 220V. The problem is that the OP is trolling at the shallow end of the market for the cheapest price, and this is what you get, mfgs playing fast and loose with nonsense ratings. Physics doesn't care and will solve the bogus claims by popping your breaker before any real power is delivered.


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## Ulma Doctor (Dec 13, 2020)

I have a similar drive that is 1.5Kw 110 to 220 3 phase. It pulls 14A @125v . I run it on a 20A 125v single phase circuit 

the 3 hp model must require double that


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## CluelessNewB (Dec 13, 2020)

I suspect the seller either doesn't have a clue what he/she is selling and is mixing up specs from a variety of different models or is purposely trying to decieve.  Either way I would avoid this one.


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## DavidR8 (Dec 13, 2020)

For that kind of money, I'd go with a known brand such as Teco.


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## pontiac428 (Dec 13, 2020)

To go over 20A on a 110v circuit you'll need 10 gauge wire (25A per leg or better).  You won't be using a 110v outlet receptacle beyond 20A.  Efficiencies aren't as good when stepping voltage up (it works better the other way around) so it would be better overall to run a 220v circuit from your panel to your 3hp machine.


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## Cooter Brown (Dec 13, 2020)

I have one of those running a 3hp motor on a delta table saw everthing works great with 110v input 20a breaker......


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## andrewgr (Dec 13, 2020)

Okay, thanks everyone.  Seems like it's pretty much what I expected.  I do have the ability to get 220, but it's going to mean spending $5K or so-- no electrician is willing to touch our panel; it's old and failing and wasn't wired well in the first place, so it needs to be replaced.  Then wiring will need to be run to the part of the garage that I'm putting the machines in.  So we're going to do that, but obviously that's a chunk of money that could have gone towards machinery, had this VFD turned out to be a magic box.

I appreciate everyone's help, and the time people spent explaining this to me.


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## andrewgr (Dec 13, 2020)

kb58 said:


> MKSJ is right, a real 3hp VFD uses a 30 amp breaker when run on 220V. The problem is that the OP is trolling at the shallow end of the market for the cheapest price, and this is what you get, mfgs playing fast and loose with nonsense ratings. Physics doesn't care and will solve the bogus claims by popping your breaker before any real power is delivered.



That's not true at all.  I'm not looking at the low end, I just did a Google search, and this is what came up.  I don't know which brands are the best-- I did a Google search for "VFD Best Brands", and all I got are those stupid web pages where people put up generic marketing information and an affiliate link to Amazon, so they make money when you make a purchase.  If there are high quality brands that I should know about, please tell me.  Even better, if there's a high end brand that does what this one claimed to do, I'd really appreciate learning about it.  But although there's a person in this thread saying he's using this model to do what it says it does, the consensus is that this is a kludge that's not likely to work out the way I want in the long run, so barring further information, I'll just need to wait until I can get the new panel installed and wiring done.


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## Be_Zero_Be (Dec 13, 2020)

*Beware of HUANYANG VFD's*
Practical Machinist Forum has banned discussion of them because they are so problematic.
I have different Chinese VFD from eBay that works fine.
220 1Phase input to 220 3 Phase output.
it is 10 HP rated to run a 5 HP lathe.

https://www.practicalmachinist.com/...d-vfd/huanyang-vfds-banned-discussion-338416/


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## DavidR8 (Dec 13, 2020)

Be_Zero_Be said:


> *Beware of HUANYANG VFD's*
> Practical Machinist Forum has banned discussion of them because they are so problematic.
> I have different Chinese VFD from eBay that works fine.
> 220 1Phase input to 220 3 Phase output.
> ...



A fellow in Calgary took delivery of one of those VFDs and it was DOA. 
Well unless you tapped on the side of it with a screwdriver handle. 
I just bought a Teco 110v VFD for my grinder and it was $250 CDN. 
I’m sure it would be less in the US. 


Sent from my iPhone using Tapatalk


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## kb58 (Dec 13, 2020)

andrewgr said:


> That's not true at all.  I'm not looking at the low end, I just did a Google search, and this is what came up.  I don't know which brands are the best-- I did a Google search for "VFD Best Brands", and all I got are those stupid web pages where people put up generic marketing information and an affiliate link to Amazon, so they make money when you make a purchase.  If there are high quality brands that I should know about, please tell me.  Even better, if there's a high end brand that does what this one claimed to do, I'd really appreciate learning about it.  But although there's a person in this thread saying he's using this model to do what it says it does, the consensus is that this is a kludge that's not likely to work out the way I want in the long run, so barring further information, I'll just need to wait until I can get the new panel installed and wiring done.


Okay, fair enough, but don't use low cost as a reason to buy.

A VFD that uses single-phase input 110V is unusual, and it's very unusual that it outputs 220V. Nearly all are designed to accept 220V single-phase and output 220V 3-phase. _Assuming that you have 220V available_ (drier vent?), I highly recommend buying a 220V 3-phase machine and using a VFD, but only if you need variable speed of course.


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## hman (Dec 13, 2020)

Regarding current draw ... one of the questions asked was about a manual and the current draw.  The seller responded that you need 20 amps.  Others have pointed out that it would probably take more current than that, and it sounds a bit low to me as well.  Also note that one of the first bullet points in the description says "The vfd only supports light load motor."  Strange to call a 3 HP motor "light load!"  Personally, I'd tend to avoid this VFD.

@andrewgr - I think spending the $$$$ to get your panel upgraded would be a very good investment.  From your description, it sounds like a fire waiting for a time to happen.  Stay safe!


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## metric_taper (Dec 13, 2020)

John O said:


> Isn't 2.2 Kw at 220 V 10 A


At 110VAC, 2.2Kw is 20amps, but that assumes this is 100% efficient. They use a voltage double circuit, capacitors and steering diodes to pump the voltage to the DC input. This is over 311VDC some losses, but closer to 340VDC with 240VAC as that is the distribution standard. 110/220 are archaic.
My experience with Huangyang VFD, it failed in my shop on power up test. Very loud bang, which I assume was one of the DC filter capacitors. I had to wait for a replacement from China. But I was unimpressed with the quality. Also this is not a sensorless vector drive, so it will not do high torque low RPM motor operation. But I'm guessing they have improved on their component quality by now. $260 is pricey for this brand.
I'm with the other posters that this idea of 120VAC input should be canned. However for lower wattage, this unit may be OK. 
When I go to the  Precision Matthews Lathe and Mill web site, I have no clue what models the OP is looking at. 
My experience on large lathe with 7.5HP motor, I use a 10HP VFD to drive it. I will never use the full rated HP of this lathe, so I'm not worried about derating the normal 2:1, mainly for the input diode current limit using single phase source.


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## andrewgr (Dec 13, 2020)

kb58 said:


> Okay, fair enough, but don't use low cost as a reason to buy.
> 
> A VFD that uses single-phase input 110V is unusual, and it's very unusual that it outputs 220V. Nearly all are designed to accept 220V single-phase and output 220V 3-phase. _Assuming that you have 220V available_ (drier vent?), I highly recommend buying a 220V 3-phase machine and using a VFD, but only if you need variable speed of course.



Could you expand on the last sentence?  I was under the impression that even if I have a 220 feed, I'd still need a VFD to go from one phase to three phase.  I'm not sure what you mean by "if you need variable speed".


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## Cooter Brown (Dec 13, 2020)

Screw the VFD..... If you have 220v 1PH all you need to do is get a static phase converter for like $50....... Its just a relay and a couple start capacitors.... But they work great....









						HD 3 - 5 HP Static Phase Converter Mill Drill Saw MADE IN USA Single to three  | eBay
					

3 to 5 HP STATIC PHASE CONVERTER. Bench grinder. Chop saw (1HP & under). Thickness planer. Product Line: STATIC WAVE. Table saw (2HP & under) Band saw (belt drive). Drill press (2HP & under). Radial arm saw.



					www.ebay.com
				




I have this one and was using in for a 3hp 3ph motor on an air compressor before I got the new shop.....


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## andrewgr (Dec 13, 2020)

Cooter Brown said:


> Screw the VFD..... If you have 220v 1PH all you need to do is get a static phase converter for like $50....... Its just a relay and a couple start capacitors.... But they work great....
> 
> 
> 
> ...



I see.  Thanks!!!

I'm used to being competent at the things I do.  Nearing retirement, I'm trying some new things-- failing doesn't seem as awful to me as it used to.  But it sure is humbling to be a complete novice surrounded by professionals and near-professionals!


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## hman (Dec 13, 2020)

EVERYBODY here started out as a novice, and ALL of us are novices in innumerable fields.  

There are several ways to get to 3 phase - static phase converter, rotary phase converter, and VFD are the most popular.  There are advantages and disadvantages to each.  The advantage of a VFD is in the "V" of the abbreeviation - variable.  It allows you to change the speed of a mill or lathe with just the turn of a dial.  If all you need is a motor running at a the rated (single) speed, then you should consider either a static or rotary phase converter.  They're generally less expensive (as @Cooter Brown has pointed out).


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## mksj (Dec 13, 2020)

I think it might be helpful to indicate what you want to power and what your needs are. A static converter works in some applications but you loose 1/3rd of your Hp. It can also cause some surface finish issues because it is not true 3 phase, and you also need to know which is the generated 3rd leg/phase and this should not be connected to transformers and electronics. A VFD can also be a bit more complicated to install and is made to power the motor, not operate the machine. You use low voltage input connection on the VFD to tell it what you want to do, not the machine controls like contactors and so forth. VFD's come in many variants, until several years ago they operated off of voltages of 200V and higher, some of the newer lower Hp models now have voltage doublers which allows them to operate off of 120VAC. The maximum size I have seen is 1.5Hp single phase 120VAC VFDs that will output 3 phase 230VAC. The limitation is typically single phase circuit is 20A, and that limits the maximum output power. When a manufacture talks about light duty, it may mean a 3 Hp motor that is delivering 1.5-2Hp worth of output/work. So may be fine for spinning a saw blade, but start cutting hard and it will stall. Same is true of a static converter.

The largest single phase 240VAC input VFD's usually is 3 Hp and very few go to 5 Hp, a VFD designed for 3 phase input needs to be derated usually by a factor of 2 to run on single phase. So if you wanted to run a 5 Hp motor, you would need a 10 Hp 3 phase input VFD and you could run it off of single phase. This is because of how the power is delivered to the input, and what limits single phase input VFD's.

So a lot of the cheap eBay and Amazon VFD's may have ratings, but they do not specify the operating conditions that is clear to others. They may work for some people, others not. You can spend a little more for say Teco, Hitachi, Fuji VFDs that are much clearer about their ratings, all of them can be a bit challenging at first to understand. There are some great on-line videos that go through how to connect and program something like the Teco L510, and other VFD's worth a look.

If you have a marginal electrical panel, the last thing you want to do is overload it and possibly have a fire. Better to be safe and do it right the first time, I have seen some scary electrical work and it can be very dangerous.


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## andrewgr (Dec 13, 2020)

mksj said:


> I think it might be helpful to indicate what you want to power and what your needs are.



Let me say, "Thank you" again for your patience and help.

I'm planning on a lathe: a Precision Mathews PM-1340GT, which is 2 HP and comes either 1 phase or 3 phase.
I'm also looking at a mill, but it looks like it runs on 110 20 amp; even if I got a different model, I'm sure it wouldn't draw more than the lathe.

I'm just a pure hobbyist.  I won't be making production runs of anything.  My initial use case is making lightsaber hilts, lightsaber stands, and tools for my (small) workshop.  I know that it's more lathe than I need, but I'm in my 50s, I'm aiming to retire in 5 years, and I can afford the extra $1K or whatever it is more than a model that's a step or two down.  Also, I don't know exactly where this hobby will take me-- it seems reasonable to get the best my limited space and budget will accommodate.


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## metric_taper (Dec 13, 2020)

andrewgr said:


> Could you expand on the last sentence?  I was under the impression that even if I have a 220 feed, I'd still need a VFD to go from one phase to three phase.  I'm not sure what you mean by "if you need variable speed".


That is one of the real good reasons to use a VFD. This stands for Variable Frequency Drive. VSD is the same thing, this term used more in Europe, for variable speed drive. These work by taking your AC input, and rectifying it to DC, then chopping it up to AC but at a much higher frequency pulse rate, as it's a duty cycle. It is all controlled with special purpose microprocessors. I have removed all single phase motors from all my metal machining equipment.  And it's for this purpose. I never change the belts on any of my machines. I get better then the original spindle speed range. I have two lathes, one with a 2HP motor (it had a 1HP single phase as purchased a 10x24 bench top), and a 18x40 lathe with a 7.5HP motor. That has a gear head, and I do change them for the speed ranges. The only time I mess with the VFD speed is for real slow single point threading, or driving a tap or die. A drill press with a 1HP (belt drive), a vertical mill with a 2HP motor (belt drive), and a horizontal mill with a 3HP motor (this has a Lima conversion system as it was originally an overhead lineshaft driven machine).
Looking up your lathe;  Precision Mathews PM-1340GT;  You most likely will not get the real benefits of a VFD as it's a gear head lathe. Nice specifications, D1-4 spindle nose. MT5 spindle taper, 1-9/16" spindle through hole. Made in Taiwan. I think this is a great lathe, for a life time.
It is a bench style lathe. The only issue I had with my much smaller lathe, was heavy cuts, like parting operations. It would dance on the floor, mounted on a sheet metal lathe stand. My fix was to get a 2" piece of steel, as large as the base of the lathe, mark the bolt down hole locations and drill and tap this base. This was placed under the chip pan and the sheet metal base was bolted from below to the 2" steel plate. That made the lathe stop flexing. It would go into harmonic oscillation and 'dance' on the floor. For reference I got this lathe in 1977 Jet brand.


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## martik777 (Dec 13, 2020)

andrewgr said:


> Okay, thanks everyone.  Seems like it's pretty much what I expected.  I do have the ability to get 220, but it's going to mean spending $5K or so-- no electrician is willing to touch our panel; it's old and failing and wasn't wired well in the first place, so it needs to be replaced.  Then wiring will need to be run to the part of the garage that I'm putting the machines in.  So we're going to do that, but obviously that's a chunk of money that could have gone towards machinery, had this VFD turned out to be a magic box.
> 
> I appreciate everyone's help, and the time people spent explaining this to me.



I use my dryer outlet (in parallel) which is close to my shop. A 1HP motor only needs 3A at 220v


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## mksj (Dec 14, 2020)

OK, very helpful to know what you are planning. I had a pm-1340GT, have probably done 50 or 60 VFD installs on that lathe, and numerous others on other machines. My recommendation is to go with the 3 phase motor and the VFD. You only need a 2 Hp VFD, I recommend the Hitachi WJ200-015SF sold through QMT or online vendors, because everything is already worked out for this model. This particular lathe greatly benefits from the use of a VFD. You get soft start, very fast braking on the order of 1-2 seconds, variable speed, and a lot of other VFD features. That particular VFD will run off of a 230VAC 20A breaker, although the manual recommends 30A. Everything is spelled out in this previous thread, the most current wiring and programming parameters are listed on the last page. By flipping the motor pulley you can convert it to a single belt speed lathe, but you still need to use the gearbox to some degree. The VFD range is around 20-100 Hz. If you have some questions when you get into it, I can give you some assistance, just PM me.








						Pm1340gt Lathe Basic Vfd Control Conversion Using The Stock Control Board And Switches
					

Many individuals buy the PM1340GT lathe as a 3 phase machine with the intent to convert it over to a VFD system, the usual VFD that is used is the Hitachi WJ200-015SF. Unfortunately the conversion often requires a somewhat complex and costly conversion process to optimize many of the VFD...




					www.hobby-machinist.com
				




As far as what you can do on the lathe, David Best completely tricked out his 1340GT, he works a lot in SS and take some monstrous cuts and pushes his machines hard. It hasn't let him down. Sure you can get a bigger and heavier lathe, but it will cost you 2-3X as much and accuracy wise there will be no difference. I have had both, so can verify that they both do great work. It is all to a price point, but if you want a very nicely built lathe, I recommend the 1340GT. I sold mine to a full time gunsmith when I moved, he had a bigger lathe but ended up using the 1340GT for most of his work.








						PM1340 - the Best & Jacobs Full Custom Edition
					

It’s been several months since I took delivery of, and posted about my PM1340 lathe.   It's time for an update since I’m nearing completion of what started as a straight forward VFD conversion project, and then took on a life of it’s own and led to a substantial customization of the stock PM1340...




					www.hobby-machinist.com
				




On the mill, depending on the model and Hp, you should be fine on a 20A 240VAC circuit. A 3 Hp motor may or may not be ok on a 20A circuit, there are different factors that come into play. One advantage of a VFD (variable speed models)is the soft start is less likely to trip a breaker.


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## metric_taper (Dec 14, 2020)

andrewgr said:


> Okay, thanks everyone.  Seems like it's pretty much what I expected.  I do have the ability to get 220, but it's going to mean spending $5K or so-- no electrician is willing to touch our panel; it's old and failing and wasn't wired well in the first place, so it needs to be replaced.  Then wiring will need to be run to the part of the garage that I'm putting the machines in.  So we're going to do that, but obviously that's a chunk of money that could have gone towards machinery, had this VFD turned out to be a magic box.
> 
> I appreciate everyone's help, and the time people spent explaining this to me.


The start of your post did not explain why you were looking at a 110v to 240V VFD. And the title is misleading.
So your problem is not having 240VAC electrical outlets in the place where you will put the machines.
It is not rocket science. And pretty sure some youtube videos will point you in a direction to do this yourself.
You can run a 240Volt extension cord. If a more permanent solution is wanted then drilling holes in the wall studs, or running conduit is a learnable building technique. $5K is way more then an electrician should charge. Appears they want to change out the whole panel. It was safe when it was orginally installed (the panel and wiring). Assuming no hacks messed with it, and produced fire hazards (e.g. too small wire with too large fuse), you should be able to add a new 240 volt circuit to an outlet box. Unless this is pre 1950s, why change it, unless it is under sized. And even that can be done by you with a little research.


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