By continuing to use this site, you agree to our use of cookies. Find out more
Forum sponsored by:
Forum sponsored by Forum House Ad Zone

Selecting a VFD for a Harrison lathe.

All Topics | Latest Posts

Search for:  in Thread Title in  
Daniel Grant04/11/2018 14:04:13
23 forum posts
7 photos

Hello all

I could really use some help understanding VFD’s. I have recently bought a Harrison 140 from a school and it runs on 3 phase, and 380v. The lathe came with a pillar drill that is also 3ph, but seems to run on either 220v or 380v.

Here are the questions I have:

  1. I’ve been told it’s essential to match the VFD to the motor, but I can’t find a VFD that outputs 1.1kw the lathe requires, do I just have to exceed it?

  1. Is there an advantage to running the pillar drill on 420v over 240v as I can’t find a VFD that takes 220v to 380v and can output 250w. Most seem to start at 1.5kw and are twice the price.

Many thanks


Daniel Grant04/11/2018 14:06:27
23 forum posts
7 photos

If it helps here is the info from the label on the motors:

Lathe motor:

Class E

Frame: 66A

Volts: 380-420


F.L Amps: 3.0

F.L speed : 1400

Hz: 50

Rating: cont

Kw: 1.1

Pillar drill motor specs

Class: E



F.L Amps : 1.2 or 0.7

A label that’s been worn reads : 240/420-460/ 1740 / 60hz

Voltage: 220 or 380-420

F.L speed: 1440

John Haine04/11/2018 14:20:53
4630 forum posts
273 photos

When it says the lathe runs on 380V, that's the phase-phase voltage. Phase to neutral is 230V. You need to determine if the motor is star or delta connected - if it is star then it may be able to reconfigure the terminals for delta to run off a standard VFD. There is probably a covered terminal block on the motor, if you can remove the cover and take a photo and post it here we can say more.

There is no problem using a VFD that can output more power than the motor needs. Usually there is a programmable current limit that can be set to match your motor.

The pillar drill motor can probably be wired star or delta so you can run it from a standard VFD. Again a photo of the terminal block would help.

Brian H04/11/2018 15:18:58
2312 forum posts
112 photos

Have a word with Usual disclaimer but I found them very helpful and knowledgable with running my Alexanda T&C grinder which is fitted with a dual voltage motorBrian

Jon04/11/2018 16:09:31
1001 forum posts
49 photos

1.1kw seems very little on the 140, most are 2.2kw 3ph 400v.

Since its a massive case size has to be 14" dia on my old 140 1 1/2hp 1ph 240v, i would be tempted as the easy way out to change the motor for a 3hp 3ph dual voltage modern type but be prepared to make or modify the plate mountings and or the 2 pulley belts.
Whilst here my old 140 used to draw at least 13A 240V on startup. Old motor probably needed rewiring etc = not worth it when can get modern new for same price or less.
Running it in VFD config will still be able to control by the clutch with no faffing about of any feedback wires to invertor.

Inverters do exist to run 400v from 1ph 240v, the way my M300 runs the last 8 years, but it will cost big time.

john fletcher 104/11/2018 16:58:01
785 forum posts

Several of my friends bought Huanyang inverters and I wired them up, very easy. One lathe also came from a school and it to was a Harrison 140 nice machine. I made a remote such that they could us the existing controls. There is a thing on Utube showing some one doing the programming, which later I copied, to late for me as I had managed without. The motor terminal block was easy to alter, just moved the links and the coolant pump I wired a 4 micro farad capacitor across a pair of terminals, so now it runs from a 13 amp socket. I did wire a contactor BEFORE the inverter to give No-volt release. The capacitor was from an old fluorescent light fitting. Some of the inverts came from Leicester others from Germany. Be quick with Germany ! Nearly forgot ,inverters cost from £98 to £120 for the same thing and are still working 4 years later. John

Neil Wyatt04/11/2018 17:32:33
18992 forum posts
734 photos
80 articles

The "Voltage: 220 or 380-420"

means you can easily rewire it as delta or star. There should be moveable bars (and usually a sticker showing the arrangements) in the terminal box.


(Sorry for the SHOUTY font)

Daniel Grant06/11/2018 20:41:48
23 forum posts
7 photos

Ib0491285-d863-4565-9f52-aa3a781ee3b7.jpeg82240fec-d636-43d7-a670-b291996d0b1b.jpegThank you all for your advice, I’ve done a little reading around delta and star configurations and the motor wiring doesn’t look like either! I’ve tried to add a few pictures, one of the terminals on the back of the motor, one of a sticker inside the motor casing and one of the new lathe (with my previous lathe in front!) From looking online the lathe looks much more like a Harrison L5 than a 140, not too sure about that 2a027698-6f3c-456a-97eb-4011314b5c27.jpeg

not done it yet06/11/2018 22:04:34
6736 forum posts
20 photos

The lathe is wired star and the star point is inside the motor. Unless that star point can be broken and new leads brought out to those connections, it will require a 230 to 415 inverter. Likely cheaper to fit a new motor wired delta and buy a far cheaper 230V output VFD.

The pillar drill can be changed to delta, by changing bridging strips, if wired star. It could then be run from a 230V output VFD.

Kettrinboy07/11/2018 08:29:00
94 forum posts
49 photos

Your lathe looks to be a 140 and not an L5 , while the bed and carriage are similar looking between the two machines the headstock on a 140 is a different shape, ive got an L5 btw.

regards Geoff

john fletcher 107/11/2018 09:21:27
785 forum posts

I'll try and send you a copy of talk (the text) I gave to the club on what you are looking for. regarding altering the motor. John

john fletcher 107/11/2018 09:33:07
785 forum posts

Back again Daniel, send me a PM, can't find how to contact you. It might be tomorrow now . John

SillyOldDuffer07/11/2018 10:13:09
8492 forum posts
1896 photos

Being electronic VFDs are likely to get more capable and/or cheaper over time. It pays to keep an eye on what's currently available because I was going to tell Dan what he wanted is a bit special and a bit expensive. Actually buying a suitable VFD appears to be much easier and less costly than it was last year! A couple of minutes on ebay found this cheap example for £94.99



Edit: link to ebay got mangled.

Edited By SillyOldDuffer on 07/11/2018 10:14:43

Daniel Grant08/11/2018 18:28:28
23 forum posts
7 photos

I think I’ll give Direct Drives a call tomorrow. Digging around on eBay I came across VFDs claiming to switch from single to 3 phase, and increase the voltage from 220 to 380 for £64. A compariable one from DirectDrives was almost 10 times the price, I’m a little concerned the eBay price has to be too good to be true!

John - I’ve dropped you my E-mail address on a OM

Thanks again for all your help.

norm norton10/11/2018 11:19:56
183 forum posts
9 photos


The 140 is a lovely lathe - well done getting it. I hope you have got the tailstock as well and the big 4-jaw chuck that the school might have had. The 140 was Harrison's later, metric version of the LS5.

I fitted a metric shaft 1.5kw 240c 3 phase motor to mine. I just cannot remember if I had to modify the pulley bore. I have feeling it went straight on the new motor. The motor fitted the existing lathe frame with just some 2" sleeves and longer bolts to raise the motor. This all suggests that Harrison had fitted a modern spec motor. Measure your existing motor's shaft diameter.

I went to Newton Tesla and bought the motor, Mitsubishi VFD and a dongle controller together. It will cost you bit more than shopping around on eBay but you will have a nice system with start/stop, forward/reverse, jog/run and speed all on the controller in front of you. If budget is an issue then go it alone but you need to be confident in your abilities in programming and handling hefty voltage wiring. You MUST NOT start/stop the motor by breaking the supply into or out of the VFD. Wire the VFD directly to the motor and do not use any of the Harrison control switches.

I actually fitted a 2-pole motor (rather that the usual 4-pole) as it gives me the possibility of double the usual lathe speed. The 140s were built for it and you can get front plates that show the doubled gearbox RPM. To be honest I rarely use the higher speed, but I do run the lathe a half motor speed most all of the time and it is much quieter. The motor is perfectly happy for the usual light and moderate load jobs.

You can get some extra change wheels and will be able to cut all the imperial threads directly from that metric gearbox.

Edited By norm norton on 10/11/2018 11:22:31

Nigel Bennett10/11/2018 11:47:43
456 forum posts
20 photos

Speak to the chaps at Transwave - advert on the right somewhere. Really helpful guys who know their stuff. I've bought two VFDs off them for a S7 and a Boxford 280. I've also heard good words from Newton Tesla as Norm says above.

Ian P10/11/2018 12:32:02
2578 forum posts
114 photos
Posted by SillyOldDuffer on 07/11/2018 10:13:09:

Being electronic VFDs are likely to get more capable and/or cheaper over time. It pays to keep an eye on what's currently available because I was going to tell Dan what he wanted is a bit special and a bit expensive. Actually buying a suitable VFD appears to be much easier and less costly than it was last year! A couple of minutes on ebay found this cheap example for £94.99


Edit: link to ebay got mangled.

Edited By SillyOldDuffer on 07/11/2018 10:14:43

Surely the picture shows the input voltage range, If it generates 380V from 220 its the bargain of the century!

Ian P

Daniel Grant04/01/2019 15:32:43
23 forum posts
7 photos

Two months on and I’m still not there with this lathe!

Since the last post I have bought a 2.2kw (3hp) VFD which incorrectly claimed to increase the voltage to 380v. I then bought a single phase 2hp motor, but it vibrated so much on the bench tools fell off the wall! Yesterday I collected a 3hp, 3 phase motor with the view to use it with the VFD. Unfortunately when connected tthe VFD it turns a couple of revolutions then spits out an Error 1 code (short circuit / current overload)

I checked the resistance between U1-U2, V1-V2 and W1-W2 and they were all between 2.1 and 2.4 ohms. There was no connection between U,V or W or to the casing. Any thoughts on what could be happening?

When I went to view we weren’t able to get the motor running using a 220v supply and capacitor, or by connecting U to Live and V and W to Neutral without the capacitor, because of this the chap I was buying from gave it to me for free, so I’m not too concerned about opening it up if necessary. Below is the current configuration of the bridging bars

Any thoughts or advice would be much appreciated.




John Haine04/01/2019 16:27:40
4630 forum posts
273 photos

Looks like it's delta connected as it needs to be. The winding resistances are really irrelevant except that they all about the same and there isn't a short to the frame. The current is determined by the winding inductance, not DC resistance. Quite possibly the current limit on the VFD is being triggered by the startup inrush of the motor, it would need properly configuring to set this up. Looks like a good find for free!

Pete Rimmer04/01/2019 16:43:45
1219 forum posts
63 photos

It's very unlikely that there's a fault in that motor. You probably need to alter some parameters in the VFD. Do you have a link to the online manual?

All Topics | Latest Posts

Please login to post a reply.

Magazine Locator

Want the latest issue of Model Engineer or Model Engineers' Workshop? Use our magazine locator links to find your nearest stockist!

Find Model Engineer & Model Engineers' Workshop

Latest Forum Posts
Support Our Partners
Eccentric Engineering
Eccentric July 5 2018
Rapid RC
Subscription Offer

Latest "For Sale" Ads
Latest "Wanted" Ads
Get In Touch!

Do you want to contact the Model Engineer and Model Engineers' Workshop team?

You can contact us by phone, mail or email about the magazines including becoming a contributor, submitting reader's letters or making queries about articles. You can also get in touch about this website, advertising or other general issues.

Click THIS LINK for full contact details.

For subscription issues please see THIS LINK.

Digital Back Issues

Social Media online

'Like' us on Facebook
Follow us on Facebook

Follow us on Twitter
 Twitter Logo

Pin us on Pinterest