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Which VFD?

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Mark Rostron15/11/2018 22:32:42
3 forum posts

Hi everyone. New to this forum, Bought a Colchester student - my first adventure into 3 phase! Here's the lathe, seems in good nick for its age

Seems tight for its age, motor mfg 1966

This note was tucked under the motor terminal cover

Correct me if I'm wrong, I can change the motor connections so it will run off 240v 3phase from a vfd inverter?

Saw this on another thread, would it be big enough? **LINK**

Do I need to oversize the inverter?

Would it all run from a 16amp supply?

Any help would be most appreciated thankyou

not done it yet16/11/2018 09:11:05
6809 forum posts
20 photos

3 Hp is a tad over 2.2kW, so it would run from a 13 amp plug - although starting under load might be interesting. That possible problem should be alleviated by running it on a VFD.

You can change it to run in delta mode

I prefer a slightly over-rated VFD. The motor may deliver 2.2kW but will not be 100% efficient. The VFD in the link appears to have adequate overload capacity. There may be cheaper options, but cheap price may mean less capabilities.

Chris Evans 616/11/2018 09:11:49
2056 forum posts

That motor looks like it can be swapped delta/star to run 240v three phase from VFD.

It us usual to overrate the VFD to cover start up load. I have been running a Chinese VFD (Huangyang ?) for 6 years without trouble cost around £90. I did need the services of a clever mate to set it up, he understands the "Chinglish" in the manual having installed 5 of the same make one on each of his machines. Try ebay for a supplier.

AJW16/11/2018 09:39:42
377 forum posts
137 photos
Mark, nice machine!
I have used a Bosch inverter from that company and have found them extremely helpful should your require assistance. Capacity wise your selection should be up to the job.

Clive Foster16/11/2018 10:13:06
3135 forum posts
109 photos

Great company to deal with.

The Eaton DE1 series impresses me on value for money (I bought one on their recommendation) **LINK**.

No frequency display or knobs on the box so you need a calibrated knob somewhere if you intend to vary the speed. No 6 ft long list of parameters to set either! Apparently its intended as an almost direct substitute for an old style Direct on Line (DoL) contactor system that can be fitted by any half decent electrician. My installation is on a car lift so I didn't need speed control and can use the existing push buttons. Simples.

Need for separate box with button and speed pot is a minor pest. Objectively, I'm not totally happy with having all that electronics close enough to a machine tool to easily use the controls on the box so would use a remote box anyway with the main box out of the way. If nowt else a separate button box is a lot cheaper when you clonk it with something hefty.


Edited By Clive Foster on 16/11/2018 10:13:40

AJW16/11/2018 13:45:27
377 forum posts
137 photos
Mark, have a look at their Bosch Rexroth range cheaper as well, they can have a detachable control pad. I mounted the VFD in the cabinet and have the control panel mounted conveniently on the lathe. Takes up no room and the control unit is kept away from dirt (and swarfe!)

john fletcher 116/11/2018 16:28:22
793 forum posts

Hello Mark, your motor can be reconnected into 240 volt Delta, those three yellow wire are the Star point for 415 volt, they need reconnecting. I've fitted several (not bought ) Huangyang inverters for my model engineer friends and they are quite happy with them. I made a copy of the program which I installed in a Harrison 140 with a 3 HP motor, if you would like copy I can send you one via an email, for that I would need a PM from you with your email address. John

Nick Hulme16/11/2018 18:30:46
750 forum posts
37 photos
Posted by not done it yet on 16/11/2018 09:11:05:

I prefer a slightly over-rated VFD.

If you use decent equipment, ABB, Siemens, Jaguar, Mitsubishi etc.then this is entirely unnecessary.
It might be required if buying cheaper, lower quality drives but I only have experience with decent kit.

Nick Taylor 216/11/2018 19:20:41
102 forum posts

That’s a nice old motor, late one as well LDC were broken up in 67. Another vote for HuanYang VFD, a 2.2kw model would be ideal. No need to over rate as you can use a slow ramp to start and you can set max motor current in the VFD.

I run my 3HP 1970s motor on my Chipmaster with a HuanYang and I’m tempted to buy a second one to run the Myford. My 2.2kw unit cost me less than £80 delivered to my door on eBay. It came from Germany as well.

Mark Rostron16/11/2018 20:24:17
3 forum posts

The HuanYang sounds cheap and popular. Are they fairly straight forward to install? Can more convenient controls be wired in rather than using the vfd itself?

Michael Briggs16/11/2018 20:56:47
220 forum posts
12 photos
Posted by Nick Hulme on 16/11/2018 18:30:46:
Posted by not done it yet on 16/11/2018 09:11:05:

I prefer a slightly over-rated VFD.

If you use decent equipment, ABB, Siemens, Jaguar, Mitsubishi etc.then this is entirely unnecessary.
It might be required if buying cheaper, lower quality drives but I only have experience with decent kit.


Zan16/11/2018 21:45:15
312 forum posts
20 photos


Hi mark

I hav the identical machine and converted it. If you use a vdf, there’s a lot of work needing to be done. The on off switch is built into the handle, and that has to be connected to the digital control. All the existing switch gear has to be ripped out as you cannot have any switches between the vdf and the motor. I set mine up to give a speed range of 30 to 65 hz via a pot mounted on the drip tray which is very handy giving a subtle speed range without changing gear, great when facing.

The pump which I no longer use works with a pair of capacitors to simulate 3 phase. I fitted a contractor as a master on off. It took a while to get  all this sorted, but it isn’t difficult as you deal with one section at a time and get that working then move on. It works well from a 13 amp plug. Most of us rarely force these machines, they are designed for heavy action and it won’t be often that you get even close to full power. In any case the vdf can be set to limit the maximum current supplied to the motor. The soft start is a great bonus. Give me a pm if you want more details

Edit.  The contractor I just switches the 240 v input to the vdf.  Your motor is dual voltage and it’s just about switching the wires over.  The lathe vdf conversion was a doddle compared with converting my Bridgeport!  

Edited By Zan on 16/11/2018 21:50:08 I have also fitted a vdf  and new motor onto my drill.  So easy to July to min speed when countersinking after drilling. Well worth the cost.  I’m a great fan of them one on the Myford as well!

Edited By Zan on 16/11/2018 21:53:00

J BENNETT 116/11/2018 23:57:17
55 forum posts

Looks like the brand new machine I had when I started my apprenticeship in September 1966! Although I was an electronics apprentice it gave me life long interest in machining. I just wish I had the space for one. Hope you enjoy it as much as I did!

Mark Rostron26/11/2018 12:46:08
3 forum posts
Again thanks for the help everyone, had the lathe working from the huan yang vfd yesterday. Put it under some load no problems at all. Just need to sort out some switchgear and hide the vfd away.
Neil Wyatt26/11/2018 13:02:42
19033 forum posts
734 photos
80 articles

One nice feature of a VFD is soft start, which overcomes the need for something which can handle a big starting surge.


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