VFD – which is best please ?

[Former MemberParticipant @formermember12892]

[This posting has been removed]

[Former MemberParticipant @formermember12892]

[RobCoxParticipant @robcox]

Personally I'm very happy with Weg VFDs. I've got 6 of them running various machines and have proved very reliable.

The instructions are comprehensive and they're in English, not Chinglish. The price is reasonable, not rock bottom or sky high.

Rob

[john fletcher 1Participant @johnfletcher1]

Six years ago three of my friend bought via Ebay, Huanyang 2.2KW inverters for around £80 each, they haven't given any problems and are still working. The inverters are mounted in a ventilated, earthed metal boxes. More recently, one bought another for £45 for his surface grinder, so must been happy with his previous purchase. Whilst the inverters are rated as 2.2KW, the program can be easily adjusted to suit smaller motors currents. With a bit of guidance they made their own remotes. I should mention all three used second hand motors and it is usually very easy to reconnect a 3Ph motor from Star to Delta. Should you go along that route I can provide you with a copy of the program which they are using. John

[SteviegtrParticipant @steviegtr]

I have a Toshiba & a Omron. I used to install Jaguar imo. They are great but i would suspect a bit expensive when new.

Not heard any horror stories of the far eastern ones. They all seem reasonably priced.

Steve.

[Harry WilkesParticipant @harrywilkes58467]

Fitted my S7 with Jaquar Cub which I purchased from Transwave good after sales and more than happy with the performance of the VFD

H

[David JuppParticipant @davidjupp51506]

Major brands may cost more, but manuals in something closer to English, plus there is a support system where if necessary you can speak to real people.

From previous reports here, some vendors also give very good support – so that's another good option.

If you are totally confused, I'd suggest stick with a major brand or a recommended vendor.

[Neil LickfoldParticipant @neillickfold44316]

I have 2 of the IEric drives from China (IMO make them), and my cnc router uses a 2.2kw Huanyang drive. I also have a second hand VFD drive from ABB from 2003, that I was given because it kept having an intermittent fault. Turns out that the remote for the frequency pot required a voltage divider which my son made for me. All have been very reliable with no faults now. I found the ABB drive more difficult to change its settings, but that maybe because I had been setting the IEric and the Huanyang . The IEric is an economy or low cost drive for small 3phase motors.

My IEric all came from a local vendor that at the time, set up the drive to match the motor that I bought with it at the time.The 1st one was for my Myford S7. I was also lucky enough that he showed me how to go through and set up the motor and the acceleration and deceleration rates as well. My brother who is an electrician, made the box and wired it correctly for me , also suggest about the micro switch option for the motor stop while threading. There is a thread about that and a video in the last two weeks.

The main issues, is to read the manuals first, and also to have a plan on how you want to control the motor. Just from the unit itself , or with some remote system where the On Forward Off Reverse switch is a 3 way switch that replaces the original Myford one, or on a control panel with push button switches and variable pot etc.

Neil

Edited By Neil Lickfold on 30/12/2021 21:31:35

[Michael CallaghanParticipant @michaelcallaghan68621]

Please what ever you don’t purchase one off eBay. I have know connection with this company bar for purchasing three inverters from over the years with very good backup. The company is. Inverter drive supermarket. U.K. company and good prices and very good customer care

[EmgeeParticipant @emgee]

Posted by Michael Callaghan on 30/12/2021 22:09:46:

Please what ever you don’t purchase one off eBay. I have know connection with this company bar for purchasing three inverters from over the years with very good backup. The company is. Inverter drive supermarket. U.K. company and good prices and very good customer care

What good reason do you have for not purchasing a VFD from eBay ?

I don't need a VFD but would not hesitate to shop on eBay, see John Fletcher's report earlier.
Buying the package from Inverter Drives can be a very expensive option especially if you have to pay extra for a filter.

Emgee

[Pete.Participant @pete-2]

I recently bought an Invertek inverter from inverter drive supermarket, 1/2hp drive, £96 plus tax so very reasonable for a UK manufactured unit, IDS also do an easy start guide for this range of inverter, which is an excellent illustrated guide that goes through all the settings needed in a genuinely easy to understand manner.

I also like to buy local for environmental reasons, this may not bother you but if a product doesn't have to be shipped across the globe and the manufacturer is in a country that handles industrial waste in a responsible manner I'll always put their goods further up my might buy list.

[John HinkleyParticipant @johnhinkley26699]

I'm with Emgee on this one. I've bought four VFDs from eBay over the last few years. Two HuangYang and 2 no-name ones at the cheaper end of the market. One of the latter just stopped one day and I can't get it to work again. The other cheapo continues to give reliable service on the shaper. Both HYs just keep going totally reliably. Don't forget, although Rolls-Royce cars never break down, they do sometimes "fail to proceed"!

John

[Mike PooleParticipant @mikepoole82104]

A feature that is worth having on a VFD is sensorless flux vector control, this has the ability to calculate the rotor position and can maintain good torque down to low frequencies. Different manufacturers call this feature by different names but they usually include one of the words or more. It is not necessary to understand how it works, just that it does improve performance at low speed, it may need to be selected when setting the parameters. It is worth remembering that to take a decent cut on large diameter work it will help if the belts and back gear are used to slow the lathe and thus keep the motor speed up, when you slow the motor the power is also decreased so at low motor rpm you will also lose power. Mechanical speed reduction will multiply the torque and thus maintain the power. VFD control is wonderful but is not magical. It transforms the lathe and I fully recommend one but although it will help a lot to minimise belt changes do not expect to never have to change the mechanical ratios.

Mike

[AJAXParticipant @ajax]

Another vote from me for inverter drive supermarket.

I have 5 WEG inverters on different machines and they all work flawlessly. They are simple to wire up with start, stop, e-stop, direction and speed control.

Don't waste your money on a pre wired package that will cost you several times the parts cost.

I don't like the Chinese inverters available on eBay. My reasons include the fake CE markings (I have been in contact with trading standards), lack of grounding, and electrical shocks from the machines they are connected to.

[SteviegtrParticipant @steviegtr]

Chipping in again. It is a bit of a can of worms. As i previously stated i have 2 branded versions. The Omron has a 160 page manual. Enough to scare most unelectrical minded person away. It has so many parameters that the eastern models do not have. But you will pay a premium in the price. Have a look at my video where i talk about the inverter & the controls + what you can program into it. Many of the forum members may find this video of some aide if thinking of going down the inverter /VFD route. The nearest new Omron i can find is circa £390. Yes very expensive for a hobby machine. Which probably gives the imports eastern made ones a bonus on price. Beware if buying from another country as there could be various duties to be paid. Take care & a nearly Happy new year to all.

Steve.

The myford lathe with a 3 phase motor

Edited By Steviegtr on 30/12/2021 23:02:33

[EmgeeParticipant @emgee]

Posted by AJAX on 30/12/2021 22:41:18:

Don't waste your money on a pre wired package that will cost you several times the parts cost.

I don't like the Chinese inverters available on eBay. My reasons include the fake CE markings (I have been in contact with trading standards), lack of grounding, and electrical shocks from the machines they are connected to.

Lack of grounding will be down to the installation not being done correctly, most of the imported VFD's I have seen schematics for include an earthing connection which of course needs extending to the motor frame for protection.

Where is it stated people have received an electric shock from a machine with an imported VFD fitted ?
If there have been instances such as stated it will be because of an installation that wouldn't pass any electrical test.

Emgee

[SteviegtrParticipant @steviegtr]

Emgee is correct. To add to that it is important to make sure the earth is connected to the frame of the vfd from the 240v input & on the motor earth connection. The only thing to note is the screen from the SY cable should only be connected at the VFD & then isolated at the Motor. Giving full screening against spurious emissions from the inverter.

Steve.

[GavlarParticipant @gavlar]

Just my tuppence worth,

I've had two expensive Mitsubishi VFDs that have failed. One secondhand one and I don't know it's background or history, and one new one that failed after about five years, though given the environment it was in, maybe that wasn't too bad.

I've also had several of the cheap, no name ones from Ebay and Amazon. They are occasionaly on offer on Amazon and I've had 2.2kw units for as little as £35 iirc, though they have recently gone up a lot. I've fitted these to my own lathe as well as other peoples and am yet to have one fail. An external control box can be made for the cost of a couple of switches, a relay and a pot, if you know what you are doing and/or take the time to experiment as the instructions are not that great. These cheap units don't have all the functions of the Mitsubishis, but they are being used to drive lathe motors, and for the most part, speed and direction is all one needs to control.

The proprietry suppliers may supply a better quality product and they would certainly be the route to go if you are not competent and confident enough to go the diy route but at six times the price, I'll stick with the cheap units.

[Clive FosterParticipant @clivefoster55965]

VFD boxes are consumable devices. In particular the capacitors lead a very hard life. Real VFD rated capacitors are not cheap. Lesser types may last for a while but they will fail. The power electronics work hard too.

Inexpensive import boxes are built down to a price so capacitors will be skimped on and power electronics devices specified with little margin for overload. The drive programs will be generic and, probably, not exceptionally efficient which doesn't help component life.

For folk like us putting the box to relatively intermittent use and, generally, running well within its capabilities the $64,000 question will we put enough hours on it for it to go pop! Industrial rated boxes built to run 24/7 for 5 or 10 years will be overkill. But 10 hours a week, which is a lot of spindle time for most of us, is only 500 hours a year so getting 5,000 hour life from a cheap box would do fine for most of us.

Certainly don't cheap out on a compressor drive tho'. Even a Hydrovane has hefty start up loads.

I can afford the name brand premium so buy from IDS. Folk with shallower pockets have less choice. The worst thing about low end unbranded via E-Bay et al is that the actual source is unknown. Suppliers just buy boxes and may have lucked into some better end ones several years back but this years ones may not be so good. No way to know. Most of the really cheap boxes are built via production line rejects from Chinese brand makes. Rejects from a 24/7 long life line will still be more than up for our use. Further down the scale? Who knows?

Clive

[Mike PooleParticipant @mikepoole82104]

The pre wired packages are not expensive if you consider that it is complete and ready to go, comparing a collection of parts is hardly a fair comparison. Screwing a bare VFD to the wall and using the front panel controls is not a safe installation. A VFD is an electrical component that is intended to be installed in an enclosure that has some dust and liquid protection, the control panel on the front is intended for setup and service functions so a control station should be purchased or constructed, by the time you have collected and assembled these components the prebuilt item will start to look like a better deal. Also bear in mind that it is properly designed and constructed. The manual of a good quality VFD will have many pages devoted to enclosure requirements, wiring requirements and control of electrical noise both radiated and mains induced. Some VFDs will have a mains filter built in to prevent noise travelling through the supply wiring to other devices, this filter is not necessarily included and a separate filter should be purchased to protect your and your neighbours supply. To build a VFD installation correctly is not as simple as connecting a motor and a supply although many people do exactly that. Their neighbours may wonder why they get odd spells of radio or tv interference or they lose their internet sometimes, they may eventually notice that it happens when that bloke next door is in his workshop.

Mike

[SillyOldDufferModerator @sillyoldduffer]

Unless you know what you're doing:

• Don't buy cheap direct from the far-east. There's no support in the event of a fault or you don't understand the instructions! (Which may be poorly translated as well as aimed at experts.)
• Don't buy a top-end sooper-duper Industrial brand. These are usually bought by customers needing high-end features that they configure themselves. Not unusual for dozens of industrial VFDs to be networked together and programmed from a back-office PC. The manual is a few hundred pages of terse configuration information aimed at a specialist. Older units are particularly likely to be amateur unfriendly. Newer ones may come with defaults suited to 'man-in-shed', but don't bet on it!.

Inexpensive units bought from UK suppliers are a better bet. Support varies, but consumer protection applies. These tend to be relatively straightforward and usually come with default settings suitable for a simple installation – almost plug and play, but don't bet on it. A certain level of comprehension is needed. Best avoided if you have a hazy understanding of electric motors, control wiring, earths, EMC, what might upset an RCD, phases, star, delta, watts, and other magic. The forum can be helpful.

At extra cost there are a number of UK firms selling VFDs and VFD/motor packages specifically aimed at the amateur conversion market. These companies do most of the hard work matching motors to electronics, have a good understanding of typical problems, provide decent instructions and a reasonable level of support. Recommended for anyone who doesn't have the time or inclination to plumb the depths of electro-sorcery!

Dave

[EmgeeParticipant @emgee]

Mike

Why is a VFD screwed to the wall in the correct environment unsafe. ?

As the Start and Stop buttons are not used to Set Up parameters why are they fitted. ?

A few months ago a complete package of VFD, Motor and remote control station were purchased by the OP for his lathe.
The motor included in the package was not a Totally Enclosed with fan cooling but an open ended type to allow cooling inlet and exhaust, that in my book is not the best choice and must come into your category of unsafe.

Emgee

[Ian McVickersParticipant @ianmcvickers56553]

If I remember correctly most vfds have a low IP rating of 20 and should be mounted in an enclosure to provide additional protection. I have seen others with higher protection ratings but even these ones were enclosed. Personally I would always fit one in an enclosure with external controls. I really wouldnt like trying to hit one of those small buttons in an emergency to stop the drive.

[Henry BrownParticipant @henrybrown95529]

Personally I had no experience of using a VFD when I bought my 3 phase Warco GH1332 at the beginning of last year. I looked at the ebay VFD's and having read up on the threads on VFD's here I decided to go to a UK Based company.

Inverter Drive Supermarket are local to me, which was a real bonus, and their technical chap gave me all the information I needed to do the wiring changes in the Warco so that it worked as if it were 2 phase after I'd sent him copies of the wiring diagrams and a few photos, this included marked up wiring diagrams showing exactly what to do. Truly excellent service from them, I wouldn't bother looking elsewhere if I were doing it again.

[Anonymous]

Unfortunately the question in the OP is unanswerable. Unless anyone has done long term reliability tests on a range of VFDs?

There seems to be some confusion regarding filtering and control schemes. Most smaller VFDs do not come with internal mains filters, and do not use power factor correction at the front end. The primary purpose of the mains filter is to reduce the current pulses taken from the mains. This reduces harmonic content and improves power factor. The mains filter is concerned with conducted emissions, not radiated. The problem of radiated emissions is mostly associated with the outputs of the VFD, where the PWM waveforms have fast edges and hence a high harmonic content. These radiated emissions are normally dealt with by shielding the output signals. I'm not going to discuss the ground at one end or ground at both ends controversy!

A simplified model of an induction motor says that torque is proportional to phase current. An induction motor will be designed to produce rated current at a rated voltage and a given frequency, aka base speed. In the UK rated voltage will normally be 415V phase to phase, in star, at 50Hz. As the frequency increases the currents will fall as no more voltage is available to drive extra current through the windings. Although current, and torque, fall the speed rises, so power stays constant above base speed. As the frequency decreases the rated voltage will drive more current through the windings. In the longer term this can lead to increased resistive heating of the windings and ultimate failure. As the frequency decreases it is normal to decrease the voltage to keep the phase currents constant. Torque also stays constant below base speed.

End of Part 1 – in case I hit the wrong key and the whole lot disappears.

Andrew

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