Warco GH 18 Milling Machine

[Stuart Smith 5Participant @stuartsmith5]

That VFD is a single phase to 3 phase model. ( just do a google search).

The motor has been fitted with the wrong plate. The motor connections also show that is 3 phase.

Stuart

[not done it yetParticipant @notdoneityet]

Maybe they read my post from April 2019?🙂

[SillyOldDufferModerator @sillyoldduffer]

Posted by Gazz on 22/02/2021 19:53:22:

So now i'm wondering what the motor's rating really is,

…

I guess when i get it put on my workbench i can do some measurments, i've got a clamp meter.. but what kind of current should i see on one of the phases to the motor? 1/3rd of the total i'm expecting, i.e. 2.2 amps per phase, or does it not work like that with a VFD drive?

My advice is not to get wrapped round the axle over this: if the machine works, stop worrying and use it. If it doesn't do the job, ring Warco.

The most likely explanation is some ding-a-ling in the factory stuck the wrong label on the motor, and the label itself contains a typo. I once got a Toaster Manual with a new electric kettle – despite that the kettle worked OK.

The 3HP claim is about as meaningless as mention of the 100uF capacitor : 3-phase motors don't have 'em.

In any case, measuring volts and amps in hope of determining a motor's characteristics is liable to be misleading. For example, the Watts power on the plate could be input or output; the power rating depends on how hot the motor is allowed to get (continuous or intermittent), and the current rating could be peak amps on starting or normal running. Without the motor's specification, you don't know! And measuring electrical input doesn't mean much unless you also measure the motor's torque and power output at the shaft – not many have a dynamometer handy!

In practical terms, the VFD is 1.5kW, which is reasonable for a 900W motor, which is reasonable for a machine of that size. Does it cut metal?

Some discussion in another recent thread about the electrical safety of VFDs. They're components, meant to be safely mounted in an earthed box, not free-standing or simply stuck on a wall. Partly electrical safety, partly the need to protect them from workshop dirt. I'd leave the VFD where it is.

The plug-in control module is for setting up and testing rather than permanent use. Much better to fit a cheap replaceable external pot than to wear out the control module.

Dave

[JourneymanParticipant @journeyman]

Posted by SillyOldDuffer on 23/02/2021 10:48:17:

Some discussion in another recent thread about the electrical safety of VFDs. They're components, meant to be safely mounted in an earthed box, not free-standing or simply stuck on a wall. Partly electrical safety, partly the need to protect them from workshop dirt. I'd leave the VFD where it is.

Dave

Not entirely sure I agree with that. Surely if the item has control buttons and a display it is clearly designed to be mounted such that the buttons can be pressed and the display read, not locked away in a box.

John

[egaParticipant @ega]

Posted by Journeyman on 23/02/2021 10:57:27:

Posted by SillyOldDuffer on 23/02/2021 10:48:17:

Some discussion in another recent thread about the electrical safety of VFDs. They're components, meant to be safely mounted in an earthed box, not free-standing or simply stuck on a wall. Partly electrical safety, partly the need to protect them from workshop dirt. I'd leave the VFD where it is.

Dave

Not entirely sure I agree with that. Surely if the item has control buttons and a display it is clearly designed to be mounted such that the buttons can be pressed and the display read, not locked away in a box.

John

I suspect that most will be using remote switching and will rarely want to press the buttons on the box.

I am using a steel box on the wall with a transparent window so as to be able to see the display.

[not done it yetParticipant @notdoneityet]

That inverter has a removable control pad. Extension cables are available to allow remote mounting of that panel/pad.

[GazzParticipant @gazz]

I'm more curious what the motor is rated at really due to the wrong plate on it, thinking if i needed a replacement in say 10 years time,

I was going to mount the VFD straight on the wall (if i put it back on the rear of the mill column, then i will have to rebuild the workbenches to allow the front of the mill to be supported due to that box pushing the mill forwards so much from the workshop wall, and that would mean the 2 other benches that are part of the U shape would need their cupboards making smaller and so on)

So now i know it's better to have it in an earthed metal box i will likely mount the green warco box it's in on the wall…. on stand offs to allow air to it from the hole in the back,

And i'll fit some filter material around the opening to stop grinding dust getting in,
only talking about angle and bench grinding here, but now i know that a metal dust laden atmosphere and a VFD isnt a good thing, i'll do what i can to stop that happening.
(my tig welder has cooling paths that deliberately ensure no dust gets to the actual components, i don't think a £50 VFD will be built the same)

And i'll take the advise too about the control panel being for set up and testing, it does clip out of the VFD body and an extension cable can be fitted if i wanted, but i think that yes, a remote pot on a small panel near the mill will be better to adjust the speed (maybe that's why there's an unused grey wire between the VFD and control box, a pull through for 3 wires for a speed pot)

I've been thinking of maybe fitting a tach so i can read the actual spindle speed, that'd be more use to me than seeing the frequency the motor's getting,
Seeing the VFD display would only really be useful to see any fault codes,

[EmgeeParticipant @emgee]

Posted by Journeyman on 23/02/2021 10:57:27:

Posted by SillyOldDuffer on 23/02/2021 10:48:17:

Some discussion in another recent thread about the electrical safety of VFDs. They're components, meant to be safely mounted in an earthed box, not free-standing or simply stuck on a wall. Partly electrical safety, partly the need to protect them from workshop dirt. I'd leave the VFD where it is.

Dave

Not entirely sure I agree with that. Surely if the item has control buttons and a display it is clearly designed to be mounted such that the buttons can be pressed and the display read, not locked away in a box.

John

John, I agree with your view on this topic but since the professional engineer called it a "component" many on here now also class the VFD unit as a "component".

As I have said before IMO a VFD is a stand alone unit designed to start, stop and control the speed of an electric motor, it is no more or less than a starter to which you provide a current protected power supply and connect a motor power supply cables to the output terminals.
Provided the VFD has suitable IP protection for the environment where it is positioned and is CE rated I see no reason to fit it in an enclosure.
It may be necessary to fit a gland plate to the VFD for terminating glands for the supply and motor cables.

There is no need to fit any other controls to safely operate the motor although it is good practice to provide an accessable to the operator means of stopping the motor in an emergency.
This may not be required if the VFD control panel is positioned within easy reach of the operator.

The argument by others usually states the buttons on the VFD are only for setting the parameters but I have not found any VFD that uses the stop/start or speed controls to set unit parameters, there are dedicated control buttons for that task.

I cannot deny if the VFD is fitted inside a fan ventilated metal enclosure it will have an improved IP rating and will be electrically screened, or that having a control station mounted on the machine is a good idea but cannot agree it is a requirement set in stone, I'm sure some will disagree and state the reason so perhaps this should be posted as a new topic.

Emgee

[Clive Brown 1Participant @clivebrown1]

Warco's sales blurb make no mention of variable speed for the GH18, just 6, presumably fixed, speeds, so the VHD does not seem to be used for that.

They do however say that a new function is auto reverse for tapping. Could the VFD be a way to achieve this electrically?

[Dave HalfordParticipant @davehalford22513]

Gazz, Emgee

LINK It's things like this make it a component. Other are more obvious when they have exposed live screw heads on the connector blocks. The point about the IP number is valid if the product actually has it's own IP number.

This link tells me at any rate to leave the wiring alone.

[GazzParticipant @gazz]

I have seen a wiring diagram for the GH-18 a while back, and that was definitely the single phase motor version, it used 2 contactors for forwards and reverse and a timer for the auto tapping function (it may have also used the timer when you pressed the opposite direction button as well, but i'm not sure)

I think it was a 4 pole contactor for forwards, another other for reverse with the connections to the start capacitor switched…so it gets the 'push' in the other direction at start up to rotate backwards,
And a timer relay between them,

When the microswitch for the bottom of quill stroke is triggered it cuts power to the forward contactor and triggers the timer, when it finishes counting down it then triggers the reverse contactor,
The timer is needed as a single phase motor needs to be fully stopped before reversing it, if it's still rotating even a tiny bit, it will just carry on in the original direction when power is re-applied….this is due to how single phase induction motors work (i'm no expert here, i know just enough to be dangerous… please correct me if i'm wrong, i'm always learning)

On my GH-18 (and a few others i've heard of who mentioned the VFD with as much surprise as me at finding it and a 3 phase motor on the mill… especially with no mention of it from warco) there's just a through connector block on the inside of the back plate of the yellow control box, that's where the contactors and timer were located on the single phase motor versions.

So now to reverse the motor, a signal is sent to the VFD from either the reverse switch or the tapping bottom out micro switch, and it ramps the frequency down to zero which stops the motor (not sure if it applies motor braking as well, but the motor stops fast) it then swaps 2 of the phases to the motor (virtually i guess, as at least 2 of the phases are made by the VFD) then ramps the motor back up to it's original frequency… in t'other direction, this is accomplished in under a second.

So the motor direction switches on the front of the yellow control box are just switching signal wires to the VFD it seems, and the VFD is doing all the magic like motor braking, almost instant reverse, motor start speed ramp up etc.

Of course, being a cheap chinese VFD, it takes a few seconds to 'boot up'…. or more likely charge the capacitors up when first turned on,

And a good thing is the fan on the VFD only runs when the motor is running, sure a temperature controlled fan would be nice, but it's better than the VFD's that just turn the fan on when power is applied to it, there's space for 2 fans in the bottom of the VFD case, i can't imagine the racket of 2 of them buggers howling away, one is enough.

And no, i still havent cut any metal on it (i don't think i'll actually use it, i'll just keep it as an ornament so it's in perfect condition when i sell it on

I only just got it lifted onto the workbench today (used an engine hoise) and i've just started removing the yellow shipping grease that is slavered all over it, it looks like the measuring tape on the front of the X axis is stained by the stuff, and no amount of acetone is removing it, and i'm worried i'll take the printed markings off the tape soon (and yep, I have removed the film that was covering the tape.. but it did take me a while to notice that)

[EmgeeParticipant @emgee]

Posted by Dave Halford on 23/02/2021 17:37:44:

Gazz, Emgee

LINK It's things like this make it a component. Other are more obvious when they have exposed live screw heads on the connector blocks. The point about the IP number is valid if the product actually has it's own IP number.

This link tells me at any rate to leave the wiring alone.

Dave

Your first link goes to a problem with a 180v DC motor controller (likely a PWM unit) not an AC motor controlled by a VFD.

The second link refers to a particular VFD unit that has been connected but most likely has not been programmed correctly, there is nothing stated that makes the unit unsafe, when asked to run an operating error is flagged, that's the safety circuit doing it's job.

Just about all the VFD's I have found details for have the IP rating shown and also the CE mark, best not to buy a VFD that doesn't have both IP and CE marks.

Emgee

[GazzParticipant @gazz]

i think the VFD in my mill has an ip44 rating,

i was wrong about the green box it's mounted in that bolts to the back of the mill, it is closed at hte back not open, so the only air flow if via the hole in the bottom,

i've mounted the green box on the wall to the side of the mill, and i have the front cover off for now, i think i'll add a hole at the top and fit filters over both the top n bottom hole, and cut a hole in the front panel just so i can see the readout for any error codes etc,

Then i'll run 3 wires from it for a speed control pot, and i'd like to add a spindle speed readout sometime, but not sure where i can get to the spindle to fit either magnets or a toothed disc for an IR speed reader as used on the mini lathe.

And whilst i was cleaning the shipping grease off it tonight i spotted the wiring diagram that is for this mill, it's a great big sticker on the right side of the column, so how i missed that before i don't know,

It even seems to give some of the settings for the VFD.

[not done it yetParticipant @notdoneityet]

Would a phone call to Warco get all this explained? Then you could tell us all what is really happening.🙂

Or is that too easy?

[Michael GilliganParticipant @michaelgilligan61133]

Posted by not done it yet on 24/02/2021 06:28:45:

Would a phone call to Warco get all this explained? Then you could tell us all what is really happening.🙂

Or is that too easy?

.

Maybe, maybe not …

Conroy Stark recently ‘sent Warco a message’ …

Ref. **LINK**

https://www.model-engineer.co.uk/forums/postings.asp?th=171182&p=1

… but perhaps they respond better to ‘phone calls.

MichaelG.

[not done it yetParticipant @notdoneityet]

Posted by Michael Gilligan on 24/02/2021 08:50:31:

Posted by not done it yet on 24/02/2021 06:28:45:

Would a phone call to Warco get all this explained? Then you could tell us all what is really happening.🙂

Or is that too easy?

.

Maybe, maybe not …

Conroy Stark recently ‘sent Warco a message’ …

Ref. **LINK**

https://www.model-engineer.co.uk/forums/postings.asp?th=171182&p=1

… but perhaps they respond better to ‘phone calls.

MichaelG.

Well, I would think that if this is a new machine supplied by Warco, there should be a satisfactory response. Someone there should know and not be guessing. Further, if they don’t know, they are the people who should be unravelling this mystery. Better than a guessing game, which is what this has been, thus far.

I’m all for the KISS principle. Asking the supplier is the simple answer nearly every time.

Edited By not done it yet on 24/02/2021 09:16:56

[Michael GilliganParticipant @michaelgilligan61133]

Yes, of course there should be a satisfactory response

… The motor should also be correctly labelled.

MichaelG.

[OldironParticipant @oldiron]

Posted by Journeyman on 23/02/2021 10:57:27:

Posted by SillyOldDuffer on 23/02/2021 10:48:17:

Some discussion in another recent thread about the electrical safety of VFDs. They're components, meant to be safely mounted in an earthed box, not free-standing or simply stuck on a wall. Partly electrical safety, partly the need to protect them from workshop dirt. I'd leave the VFD where it is.

Dave

Not entirely sure I agree with that. Surely if the item has control buttons and a display it is clearly designed to be mounted such that the buttons can be pressed and the display read, not locked away in a box.

John

I agree John. Both my VFD's came with instructions for mounting on the wall. No mention of a cabinet/box of any kind.

The front control panel is for everyday use unless a pendant is added. The instructions say to mount on a wall clear of obstructions allowing a free airflow and within easy access of the machine. All the electrical connections are perfectly insulated inside the VFD so no danger there at all.

regards

[SillyOldDufferModerator @sillyoldduffer]

Posted by Emgee on 23/02/2021 19:06:54:

Posted by Dave Halford on 23/02/2021 17:37:44:

…

…

Just about all the VFD's I have found details for have the IP rating shown and also the CE mark…

Emgee

Maybe, but just in case that's an Anecdotal Fallacy, can anyone positively confirm that Gazz's particular VFD isn't a component? At the moment we don't know how Gazz's unit is labelled or what its specification is.

Could be Gazz's unit is boxed differently from the XSY-AT1 I looked at, though from the front it was similar to that in the photo, but my example had semi-shielded terminals, a fairly flimsy slotted plastic cover, and I don't recall it claiming an IP rating. It didn't look robust enough to be exposed in a workshop and – even worse – little fingers could get at the terminals.

Does anyone understand Gazz's circuit?

Is the unusual complexity related to the tapping feature? I suspect the extra switches put the VFD into tapping mode, and depend on how the AT1 is programmed. Before experimenting with the VFD I'd take careful note of the program settings so they can be put back! I guess the parameters listed on the label are what's needed for the VFD to do milling and tapping, but remember the motor label is a mistake, and the VFD label misspells CURRENET.

Dave

[EmgeeParticipant @emgee]

Posted by SillyOldDuffer on 24/02/2021 09:51:42:

Posted by Emgee on 23/02/2021 19:06:54:

Posted by Dave Halford on 23/02/2021 17:37:44:

…

…

Just about all the VFD's I have found details for have the IP rating shown and also the CE mark…

Emgee

Maybe, but just in case that's an Anecdotal Fallacy, can anyone positively confirm that Gazz's particular VFD isn't a component? At the moment we don't know how Gazz's unit is labelled or what its specification is.

Could be Gazz's unit is boxed differently from the XSY-AT1 I looked at, though from the front it was similar to that in the photo, but my example had semi-shielded terminals, a fairly flimsy slotted plastic cover, and I don't recall it claiming an IP rating. It didn't look robust enough to be exposed in a workshop and – even worse – little fingers could get at the terminals.

Dave

Dave

Nothing anecdotal about the IP rating and CE mark being shown on VFD data sheets, when you have some spare time check the manufacturer's or retailer's sites for confirmation.

You say you looked at an XSY-AT1 VFD, does that mean you viewed a picture/video and didn't physically handle the unit ?

I see Gaz is claiming IP44 for the VFD fitted in his machine.

Emgee

 

 

Edited By Emgee on 24/02/2021 11:07:38

[Dave HalfordParticipant @davehalford22513]

Posted by Emgee on 23/02/2021 19:06:54:

Posted by Dave Halford on 23/02/2021 17:37:44:

Gazz, Emgee

LINK It's things like this make it a component. Other are more obvious when they have exposed live screw heads on the connector blocks. The point about the IP number is valid if the product actually has it's own IP number.

This link tells me at any rate to leave the wiring alone.

Dave

Your first link goes to a problem with a 180v DC motor controller (likely a PWM unit) not an AC motor controlled by a VFD.

The second link refers to a particular VFD unit that has been connected but most likely has not been programmed correctly, there is nothing stated that makes the unit unsafe, when asked to run an operating error is flagged, that's the safety circuit doing it's job.

Just about all the VFD's I have found details for have the IP rating shown and also the CE mark, best not to buy a VFD that doesn't have both IP and CE marks.

Emgee

Odd, when I use the first link it goes to the exact VFD in question albeit an earlier version in june last year. The thread degenerates into buy a DC motor instead. Thread title "SAFETY ALERT for XSY-AT1 VFD inverter users"

PS Doesn't IP44 rating means that your product will be protected from solid particles that are over 1mm in size and from low velocity sprays of water from every direction.

Edited By Dave Halford on 24/02/2021 12:17:12

[GazzParticipant @gazz]

i've been trying to find where i read that this VFD might have an IP44 rating, but i can't find it again, so i am likely wrong,

But IP44 is pretty low anyway, basically it might keep big fingers out of the live terminals but that's it,

This VFD does not have a fully enclosed base for a cable gland or anything, the actual screw terminals are shielded with a screw on front cover, but you could poke things up the mains terminals holes in the bottom of the case etc.

Here's the base of the VFD with the terminal cover removed.

[Anonymous]

Posted by Gazz on 24/02/2021 17:21:22:

But IP44 is pretty low anyway, basically it might keep big fingers out of the live terminals…..

Not so. The first 4 indicates protection against anything larger than 1mm. That's a pretty small finger. The second 4 is protection against splashing water from any direction. A quick look at the manual for the VFD I bought for my Pultra gives an IP rating of 20, which is common for items considered to be components that will be incorporated into a larger unit.

Andrew

[EmgeeParticipant @emgee]

IP Ratings.

First digit – protection from foreign body and particulate ingress:
Second digit – protection from moisture ingress:

IP2
Protection against solid objects larger than 12mm (accidental finger contact).
IP-0
Not rated (or no rating supplied) for protection against ingress of this type.

Emgee

Edited By Emgee on 24/02/2021 19:56:06

[GazzParticipant @gazz]

gotya,
i would say a bare VFD of this type would not have any protection from any kind of water, be it a jet, a sprinkle or mist,

I would say a 2 maybe 3mm screwdriver tip could make contact with the terminals if poked up the holes the wires go up in the bottom (or say 6mm if a wire is not present)

Bbut it is a chinese unit made to the cheapest possible price, so we should really treat any external screws on the unit as pottentially live?

but either way, i now know i would not like any VFD to be mounted bare on a wall near a machine that can throw little chunks of metal about when in use, not to mention the possible use of a mist cooling system, or grinding in the same air space.

I have emailed warco about getting the correct motor plate for this mill, and also to ask to exchange the hold down clamping kit i bought for it, as i bought the M12 version after seeing their list showing most mills including the WM-18 they sell listed as taking that size,

And it turns out this mill has the next size down T-nut slots

[Author]

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