Restoring Beaver VBRP Mill

[Daniel RobinsonParticipant @danielrobinson12697]

Hi Rob,

I’m hoping that you have some grasp of 3 phase…..

So first off you need to take a look at the face plates of the motors on the machines….

Fingers crossed that they are the dual voltage variety, 415v /220v which means that with a bit of jiggery pokery you can make them all 220v.

Even if they are not, If your motor is internally connected for single circuit delta at 400vac, it could be internally reconnected to a 2 circuit delta for 200vac but this means you need to take it to someone who knows what they are doing and will cost…which is what I did.

Keeping the voltage the same as the mains voltage (220v) greatly reduces the cost of the inverter as it doesn’t have to induce 415v as well as create the third phase.

The main motor on my Beaver MKII is 5KW 220v 3 phase so I went for a Hyria 220v 7KW inverter (single phase in, 3 phase out but remaining at 220v) which gives a bit of overhead when the main motor starts, due to the initial draw of current to get the lump started and also powers the feed motors which are a lot smaller.

In fact I have a bit of rats nest that feeds all my machines as I only ever use one at a time being me, myself and I.

You might have an issue with the magnetic contactors for the power loss disconnection but so far, touch wood, I have not seen this happen.

The transwave I find are overpriced and are sourced from China so why not go to the source and cut out the middle man. This is a personal opinion and I would dutifully buy if it was made in the UK the same reason I bought a Beaver rather than a bridge port. You are taking a risk but PayPal protects you and so does eBay. If it doesn’t work, never arrives, or there are issues communicating with vendor then you get your money back. You can’t get better than that.

Dan

[RobonthemoorParticipant @robonthemoor]

Thanks Dan this is a large help to me. A couple of points!

How do you run Spindle motor, power quill motor, X axis & y & z all at the Same time with an vfd & have you got an purchase address for me to purchase one.

Rob

[Alan Waddington 2Participant @alanwaddington2]

You would need a suitably sized VFD for each 3ph motor on the machine

i.e you can't run 5 motors from one inverter.

A suitably sized rotary phase converter like a Transwave is capable of running all the motors at the same time.

Agree with Dan that they are overpriced, I built my own 3hp RPC for less than £50. Plans are freely available on the web, and it's not particularly difficult to knock one up.

Edited By Alan Waddington 2 on 12/11/2016 23:04:08

[RobonthemoorParticipant @robonthemoor]

Hi Alen,, just as I thought, can't run all the motor off one vfd, I'm sure I could build an RPC as you do, with all the support I get from you guys what a community we are, do you have a link to the free planes" I've not seen the mill as yet but I would suspect the the main motor I know is 4hp, but the others will only be 1/4 HP & the Y will be 110v so four motors to support, I do have a trans wave for the surface grinder & a 3hp one linked to my coolant pump on the lathe so I'm not stuck. But" be nice if the mill was self running if that's the right word. Rob

[Daniel RobinsonParticipant @danielrobinson12697]

Hi Rob,>>

You CAN run multiple motors off 1 VFD if you do not use the variable frequency function. The picture below shows the two layers of function within the invertor I bought. The first and the most important is the power.>>

Single phase in – three phase out >>

The next level (top small green chock block) is the remote or variable frequency function which I do not use and rely on the belt speeds of the machine. >>

There is a call for VFD and I understand its beneficial uses but I really don’t have the money and the machine still has variable speeds as they were designed into it when it was built. I looked at all the options with transformers, inverters and converters. The cheapest option for me was an inverter at £200.>>

[Daniel RobinsonParticipant @danielrobinson12697]

Remember when the machine was built there is only one supply to it. There is a switch board inside the “cupboard” on the side of the machine to distribute power to the other motors.

Dan

[Alan Waddington 2Participant @alanwaddington2]

It's 15 years plus since I built mine Rob, so I don't have a link to the exact schematic I used, however they all work in pretty much the same way, and there is now a mountain of free info available online. Info was harder to acquire back then.

First google hit pulls up this **LINK** which is good reading and explains a lot.

i sourced all the components from scrapyards, including a brand new 3hp motor for £10. It should actually be easier now as brand new inexpensive capacitors are readily available on your favourite auction site,

When buying a 3 phase motor, make sure it is dual voltage ( most modern ones are ) 400v/220v star/delta or similar ( it's the 220v star that's important) Also I prefer 4 pole motors as they run slower, and therefore quieter, but a 2 pole will work fine if you drop on one cheap.

Plenty of 4kw upwards motors available on ebag but they seem to be fetching between £50 and £150. I'm on the hunt for one myself to build a bigger RPC for the Beaver, but being a true Yorkshireman am exploring cheaper sources before pressing the button.

My old one has a very simple start circuit arrangement, I hit the main power switch and simultaneously flick a momentary switch to energise/drop out the start capacitor. It works well but requires a good degree of co-ordination and timing otherwise bad things happen. I'm hoping to include an automatic timer relay in the new one which can be set in M/secs, this should make starting the idler motor foolproof.

If you do decide to have a go please remember to observe all the necessary electrical safety precautions. Earthing and fusing are important and don't forget the capacitors used will retain a lethal 240v A.C charge even when switched off. A Good degree of respect is definitely healthy.

[Alan Waddington 2Participant @alanwaddington2]

I didn't know that Dan, was always lead to believe inverters should be wired direct to the motor rather than through contractors and switches etc. in fact I'm sure the VFD running my lathe states so in the manual. But to be fair I am running it as a frequency drive with speed control, forward/reverse and estop.

Do all the motors run all the time, or can you switch them in/out as you need by using the mills original switchgear ?

reading this **LINK** suggests you are correct, however there does seem to be some conditions.

but this http://www.phasetechnologies.com/phaseconverterinfo/phaseconverter_vfd.htm backs up my original beliefs.

Alan

Edited By Alan Waddington 2 on 13/11/2016 09:51:36

[Daniel RobinsonParticipant @danielrobinson12697]

Hi Alan,

Don’t get me wrong with my advice: I’m cheap to the extreme!

What you describe above by having a slave motor is the most robust and effective method of delivering 3 phase but I found sourcing a 7KW motor a little tricky (Beaver main motor is 5KW + overhead for starting 1KW + little bit for additional motors run at the same time). I even begged next door If I could take a feed from their house (your next door neighbour is out of phase with your supply so combined will give you 3 phase).

The inverters use a pulse width modulator (digital) to create the analog sine wave in three HT lines. If used at full frequency (50hz) then this is just giving power to the machine to the rated value of the inverter, in my case 7.5KW

This means that you can run as many motors or machines with many motors from a single device.

You run into problems when you start to vary the frequency.

As previously stated the magnetic contactor needs a stable frequency to maintain contact otherwise it “chatters’ at the frequency of input. This is why, when you add a VFD to a machine you remove the contactor and rely on the VFD to make the machine safe in the event of power loss.

Also varying the frequency will affect the speed of all motors attached to the machine hence having a VFD for each motor which gets hellishly expensive.

Coming back to your slave motor, the reliability is unquestioning, unless you use an under rated motor and try and draw too much current through it and you get lots of smoke… small fire.

Inverters have a lifespan… they will fail…. They are made in china (quality is variable) and are cheap at the moment, ebay 7.5kw inverter £200.

Dan

[Alan Waddington 2Participant @alanwaddington2]

You've got me interested now Dan. My mate has been running the same VFD as yours to power a two post ramp, and so far it's holding up well. Done at least 2 years without letting the smoke out.

Am I right in thinking you have wired the 3 PH output of your inverter direct to the main spindle motor and the auxiliary motors in series with no contractors / switches ? So in effect all motors run when inverter powered up

if so something that confuses me is if you reverse spindle motor rotation using the inverter, does it not also reverse the rotation of all the other motors.?

Sorry for the dumb questions.

[Daniel RobinsonParticipant @danielrobinson12697]

Hi Alan,

There are no dumb questions when it comes to learning and investigations of new techniques as it makes the one being questioned, re-affirm their beliefs on how something works.

So an inverter is a box of interdependent functions:

• Power converter which takes single phase and converts three phase using the Pulse width Modulator.
• Frequency controller (varies the clock speed to the PWM)

I am using the power converter but NOT the frequency controller. The output of the controller is three phase and as I’m not playing with the frequency controller it outputs 50Hz which is the mains power frequency.

I then plug this into the back of the machine as the manufacturer intended (plus or minus the magnetic contactor) which then goes into the distribution box to supply all the motors.

I have left magnetic contactors in some machines as they have been used as distribution boxes and to unpick that is time consuming and will mean more cash spent on a solution rather than having fun making something.

The machine has Mechanical Variable speed through belt and pulley gearing and reverse through an electro-mechanical switch which reverses the polarity of two phases to the main spindle which I’m more than happy with.

Be warned that there are situations that can cause issues. I have a MidSaw that has a transformer in it for blade welding. Although the motor was converted for 220v and will run happily on the inverter the transformer relies on 415v to run the blade welder so the solution was to put an additional transformer which takes the 220v three phase and out puts 415v three phase.. had to sell a kidney for that.

Dan

[Daniel RobinsonParticipant @danielrobinson12697]

Ah, just realised why you are thinking that I am using the frequency controller… the picture above came from a tutorial guide I have on the inverter… If you are interested I have the complete guide which shows you how to program it…..

[Alan Waddington 2Participant @alanwaddington2]

That would be really useful Dan, in the past I've struggled with understanding the programming of VFD's a combination of being an old dunce and the chinglish instructions.

If I can stick a VFD on the beaver it will be a lot quicker than building a bigger RPC. In my case there are really only two motors, the main spindle motor and the table X axis feed motor, don't think I'll use the coolant motor.

Every day is a school day it seems…….

Getting back to Rob's potential purchase, how does an auto draw bar work ? Is it a motor or an electro magnet/solenoid type affair. Just thinking it could be a stumbling block to using a single VFD unless they are single phase or maybe DC.

[RobonthemoorParticipant @robonthemoor]

Posted by Daniel Robinson on 13/11/2016 08:50:56:

Remember when the machine was built there is only one supply to it. There is a switch board inside the “cupboard” on the side of the machine to distribute power to the other motors.

Dan

That's the way I would like to go, use the vary speed on the machine, god if that works & runs all the mills actions from a vfd I will be well pleased. Thank you very much for your help👍 Keep it coming

[RobonthemoorParticipant @robonthemoor]

Posted by Daniel Robinson on 13/11/2016 13:21:16:

Ah, just realised why you are thinking that I am using the frequency controller… the picture above came from a tutorial guide I have on the inverter… If you are interested I have the complete guide which shows you how to program it…..

I was a little lost at your pitcher, but thought it maybe from a book,,, can you take a photo of your wiring set up please Dan👍

[MuzzerParticipant @muzzer]

Sorry but the suggestion that you can switch several motors in and out from the output of an operating VFD is simply wrong. And running it at constant frequency really doesn't make any difference on that score. Read the manuals carefully and you'll see that although you may run 2 or more motors on one VFD (with some brands), you have to enable the VFD with them already connected up. No contactors between VFD and motor(s).

I speak as someone who has designed / developed VFDs for production and used quite a few in anger.

Of all VFDs to try switching multiple motors from, a Chinese Huangyang or whatever is the last one you'd want to play with.

Sorry to be a misery guts.

Murray

[Alan Waddington 2Participant @alanwaddington2]

Oh oh…… sounds like it might be back to plan A after all.

[Alan Waddington 2Participant @alanwaddington2]

More interesting reading on the subject…………

**LINK**

[Daniel RobinsonParticipant @danielrobinson12697]

Hi Murray,

You know I have this working… so saying it doesn’t work doesn’t make a great deal of sense. Let’s try to understand where our views differ.

I am presenting to the VFD a single source, milling machine, the same as I would wire this into a 3 phase supply if I had one.

Can you explain switching out motors as I think this is key?

Dan

[Alan Waddington 2Participant @alanwaddington2]

Posted by Daniel Robinson on 13/11/2016 17:40:26:

Hi Murray,

You know I have this working… so saying it doesn’t work doesn’t make a great deal of sense. Let’s try to understand where our views differ.

I am presenting to the VFD a single source, milling machine, the same as I would wire this into a 3 phase supply if I had one.

Can you explain switching out motors as I think this is key?

Dan

 

Dan, the conclusion I get from the discussion in the last link is that yes it probably will work, but not for too long before frying the VFD.

Out of interest, how long has your mill been running wired in this way? so much conflicting advice and evidence on this subject, it's a minefield.

 

Edited By Alan Waddington 2 on 13/11/2016 17:55:39

[Daniel RobinsonParticipant @danielrobinson12697]

Hi Alan / Murray>>

So it looks like I'm running dumb luck…. or my bed motor is insignificant to affect the VFD control program…>>

However saying that it has been going for 3 1/2 years and through a mag contactor for the lathe (Chipmaster 3hp) and MidSaw 36" throat with blade welder again 3hp.It also powers the thickness planer, spindle moulder, table saw and pillar drill but never at the same time as I don’t have that many hands. >>

Nowhere in the programming matches the VFD to any particular motor so adding another motor independently would only present additional load (amps) which would be the same if I was to try to take a massive bite out of a lump of steel. >>

Again I have over rated the Invertor by 2.5KW so again could be “getting away with it” but measuring it from an output perspective and the power is constant and the two motors work on the machine independently or together. >>

Dan >>

[Daniel RobinsonParticipant @danielrobinson12697]

I will load the tutorial and take a couple of pic's that is the wiring for my garage tomorrow. always interested to hear another view but if its working and and someone tells you otherwise you have to question… Why?

Dan

[Alan Waddington 2Participant @alanwaddington2]

Fair play to you Dan, I'm certainly not in a position to argue with you, just trying to get my head around all the options for running my mill..

it sounds like your inverter has done a good bit of work and lasted a decent time, which considering its humble origins and low cost does make you wonder…….sometimes theory and practise can be far removed.

Al.

[MuzzerParticipant @muzzer]

Posted by Robonthemoor on 12/11/2016 22:48:41:

How do you run Spindle motor, power quill motor, X axis & y & z all at the Same time with an vfd & have you got an purchase address for me to purchase one.

Dan – this is what you responded to, apparently recommending one VFD for all of them, unless I misunderstood or you were answering a different question. Are you seriously suggesting that he runs all of these motors from one VFD? Is he allowed to turn the different motors on and off during operation – I think he'd sort of hope so.

You will find that the VFD setup requires you to program in the "nameplate" parameters, such as the base speed, rated current etc. This is what tells the VFD about the motor(s) you have connected up. Otherwise, how could it know to limit the current during startup and overload and to tune the controller for correct response?

Generally you are recommended to only switch between motors when the VFD is disabled (and the motors stationary) and use motors of similar rating. There are some VFDs that allow separate parameters to be entered for 2 different motors which can then be selected as alternatives, although again you need to disable the VFD first.

Murray

[RobonthemoorParticipant @robonthemoor]

Hi Rob,>>

You CAN run multiple motors off 1 VFD if you do not use the variable frequency function. The picture below shows the two layers of function within the invertor I bought. The first and the most important is the power.>>

Single phase in – three phase out >>

The next level (top small green chock block) is the remote or variable frequency function which I do not use and rely on the belt speeds of the machine. >>

murray this is how Dan has done it, can you put more light on it, it's not worth me even going to look at the mill if I need 5 vfds ☹️️££££££££££££££££££&££££££££&££££££&£££££ think I'll take up fishing😺

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