Looking for help for vfd for Boxford

Moper361

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Hello
Looking for help on basic ideas for suitable vfd to fit to my new second hand boxford aud.Currently its 3 phase were it is but plan to move it in the future to were i only have 240volt single phase .The lathe still has original wiring and switches in it .
The safety switches for backgear lockout .cabinate door. gear train cover and estop run of 110volt through a magnetic contactor .

I would like to still keep all these switches and safety devices in use when i change to VFD i would also like to utalise original forward off reverse switch .
What VFD would allow me to utalise all these and suit my electric motor .
I would also like to fit a foot pedal that you could depress when threading at very low speed obviuosly due to scew on chuck that would stop the motor and also brake at the same time .
I am far from being an electricial but would appreciate if i could get advice on a vfd that would cover this and ideas on how to wire it all up to work have attached best picture of motor plate and a basic wiring diagram that originally came with lathe with manual .it only shows basic motor wiring .20190721_141832.jpg20190721_141915.jpgPART_1562897426681.jpegPART_1562897816653.jpeg20190721_141824.jpg
 

Karl_T

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nearly all VFDs should meet your needs. As you are outside USA, could you pick out a few possible selections and we can make sure they will work for you. I used this vendor recently

What size is your spindle motor? get a VFD a bit oversize.

its going to take a few pictures and a bit of back and forth with questions and answers to help with the wiring.
 

Moper361

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nearly all VFDs should meet your needs. As you are outside USA, could you pick out a few possible selections and we can make sure they will work for you. I used this vendor recently

What size if your spindle motor? get a VFD a bit oversize.
The motor is 750 watt so guess thats 3/4 hp
I live in thailand and was planning on buying vfd and just take it back to australia when i travel there again .
I can lay my hand on mitsubishi Fr-d740s 1.5 kw pretty easily .but will take more of a look when im back there next week and see what else is available
 

Karl_T

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I see you got pics up. they were not there when I first responded. doesn't look hard at all to install a VFD. 750 watt is one hp.

That Mitsubishi would be a real good choice. Not sure the HY I showed supports a VFD brake resistor. The mit surely would. You might want that upgrade on a lathe
 

Karl_T

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OK been looking it all over a bit.

My approach would be to first re wire your Estop circuit to just bring in that contactor. remove the forward reverse stuff and disconnect your forward reverse switches.

install the VFD and get it to run with the VFD control panel. confirm estop drops it out and reset brings it back in.

Then install the forward reverse switches to the VFD.

You will almost certainly want to install a potentiometer to control speed.

I'd suggest placing the VFD inside your existing enclosure if it will fit. A remote wire to move the VFD control panel to visible spot is a real nice option.

Just an outline here for your comment.
let others chime in here.
 

Moper361

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I see you got pics up. they were not there when I first responded. doesn't look hard at all to install a VFD. 750 watt is one hp.

That Mitsubishi would be a real good choice. Not sure the HY I showed supports a VFD brake resistor. The mit surely would. You might want that upgrade on a lathe
Yes got the pics up .after looking at the pics of the vfd you sent the link for i have a basic understanding from the diagram .

First question i would ask is if i wanted to fit a foot switch for braking were would this be wired in ? Or would it be wired in in series with the resistor ?i would like the brake to only be used when threading at low speeds not for general turning at higher rpm example if bedal depressed lathe stops and brakes


Second question would the estop and power on off with light be wired in on the single phase lines supplying the vfd ?

Forward reverse common is straight foward

The safety switches for guards etc would they be wired in series and go common to ?

Yes a foot brake just for threading would be a great upgrade
 

Moper361

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OK been looking it all over a bit.

My approach would be to first re wire your Estop circuit to just bring in that contactor. remove the forward reverse stuff and disconnect your forward reverse switches.

install the VFD and get it to run with the VFD control panel. confirm estop drops it out and reset brings it back in.

Then install the forward reverse switches to the VFD.

You will almost certainly want to install a potentiometer to control speed.

I'd suggest placing the VFD inside your existing enclosure if it will fit. A remote wire to move the VFD control panel to visible spot is a real nice option.

Just an outline here for your comment.
let others chime in here.
Just got this message after sending my questions lol
Yes i was planning to fit vfd in original enclosure if i can after some other unused items are removed as from what i understand is magnetic contactor would be redundant .
 

Karl_T

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We will use one contactor to go through your estop and all your safety switches. Anything here opens, it drops the contactor.

contactor then goes to the VFD.

Foot switch, no problem. just describe exactly how it should work for the operator. Also does the operator turn the spindle forward/stop reverse with the panel pic above?

lets make sure the VFD you select support moving the control panel/pad and a brake resistor.
 

Karl_T

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Re read yet again.

I think you want a foot switch to quick stop the lathe?

That means forward/stop/reverse push buttons would work better. Not all VFDs support this, but many do. lets looks for that ability before your purchase.
 

Moper361

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We will use one contactor to go through your estop and all your safety switches. Anything here opens, it drops the contactor.

contactor then goes to the VFD.

Foot switch, no problem. just describe exactly how it should work for the operator. Also does the operator turn the spindle forward/stop reverse with the panel pic above?

lets make sure the VFD you select support moving the control panel/pad and a brake resistor.
Okay I understand yes the estop on off switch and safety switches can be wired through magnetic contractor to supply single phase to VFD .

The foot switch i only want to use it to Brake the motor when threading or in an absolute emergency IE if I got caught up in work piece or chuck .It is a threaded chuckand can come undone if break is applied at higher rpm .
Basically during threading operations you would press the pedal to stop and brake the motor .for normal machining or turning I would not Italian the pedal .i would just turn the forward reverse switch to off position .

Normal operation the forward reverse switch would be switched to either forward or reverse then the green button would be pushed to start the motor in direction of selected rotation .Then the forward reverse switch would be switched to off when you want spindle
Re read yet again.

I think you want a foot switch to quick stop the lathe?

That means forward/stop/reverse push buttons would work better. Not all VFDs support this, but many do. lets looks for that ability before your purchase.
Yes i only want foot stop to quick stop lathe when threading

For normal use i would use forward reverse switch without brake to stop lathe
 

Bob Korves

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Keep in mind that the VFD output needs to be connected directly to the motor, no switches or anything else between VFD motor output and motor. Otherwise you risk damaging the VFD. You can use the existing switches and contactors on the lathe to control the low voltage side of the VFD.
 

Moper361

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Keep in mind that the VFD output needs to be connected directly to the motor, no switches or anything else between VFD motor output and motor. Otherwise you risk damaging the VFD. You can use the existing switches and contactors on the lathe to control the low voltage side of the VFD.
From what Karl has put forward the estop on off switch along with safety switches etc would supply power to vfd

Then forward reverse swich connected as inputs on vfd without brake

Foot brake just for threading im not sure how this would connect in yet

Then 3 phase output direct to motor.

Im not upto speed with electronics so thats why seeking advice on unit selection that i could acheive these parameters so any input appreciated
 

Karl_T

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OK, more than one way to do this.

My first concept would be the Estop circuit as previously outlined to bring in a contactor in front of the VFD.

Then what I will call an "enable' circuit. It will go through the F/off/R switch to the start pushbutton, to the foot switch and then to coil on an enable relay. Push start and this coil will latch closed. kick the foot or turn F/off/R to off and drop this coil. Now use a second set of contacts on this relay and a second set of contact on your F/off/R switch to wire the VFD for forward or reverse. Note this idea needs two contacts on your F/off/R switch and a DPDT relay.

There may be a more clever way to do this.
 

Bob Korves

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From what Karl has put forward the estop on off switch along with safety switches etc would supply power to vfd

Then forward reverse swich connected as inputs on vfd without brake

Foot brake just for threading im not sure how this would connect in yet

Then 3 phase output direct to motor.

Im not upto speed with electronics so thats why seeking advice on unit selection that i could acheive these parameters so any input appreciated
You seem to understand the picture. The VFD power output needs to go directly to the motor, no switches or other controls in between. Some existing machine switches, especially those mounted on older machines, might have too much resistance at the contacts to reliably operate the VFD. You can check the resistance across the switches and other controls with a VOM (volt/ohm/meter).
 

mksj

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I do not recommend you use the E-Stop and safety interlocks to kill power to the VFD, if you hit the E-Stop the VFD will often free wheel to a stop, although some can use regenerative power to do a controlled braking. Typically the E-Stop and safety switched are all serially connected to the VFD low voltage input signaling so, would kill power to the run commands. You do not want the forward/reverse switches directly wired the respective VFD low voltage input because the lathe can start if you release the E-Stop or any of the interlocks. Typically what is done is to use two latching relays to for the forward/reverse commands, these are typically 12 or 24VDC. Alternative is to strip out the high voltage to the contactors and use them to switch the low voltage VFD signals. These requires replacing the contactors as the contact resistance is an issue with used ones.

Unclear on what you want the foot brake to do, if you want it to stop the lathe with braking then it just breaks the signaling pathway, but you still need some form of latching relay design so the machine does not restart when you release the brake. I have also designed systems that use momentary buttons for for/stop/rev which some people have preferred. If you have a manual brake, then you want to wire the stop switch to issue a free run command to the VFD so the VFD braking is not over riding the foot brake. You can also program the VFD for different braking rates.

Attached is a control system I designed for the G4003G which uses the WJ200 VFD, the jog circuit would vary based on the VFD. This design uses 3 pole relays, the 3rd pole could be wired to operate a coolant circuit, otherwise 2 pole relay can be used. The relays should use the snap in protection diodes that fit into the relay base to prevent reverse voltage spikes when the relays open.
 

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markba633csi

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In addition to all the above, you need to configure your motor for 220 volt as indicated on the nameplate if it is not already
Have you considered using a rotary phase converter instead of a VFD? It would eliminate a lot of rewiring
 

Karl_T

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OK ask two engineers how to do it, get three answers. I should concede mksj has more expertise in this area.

I do have the 3M corporate safety philosophy on Estop. This circuit must kill the machine NO MATTER WHAT. Some idiot mis-wires or programs something, the machine still dies. Yep, this concept just lets the machine coast to stop on E-stop but you cannot do anything program wise to have it not stop. With this concept Estop is only for an emergency - never push it for normal operation. Then set the Estop when you are done. Now your kid etc. is unlikely to accidently start it up.
 

Moper361

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OK ask two engineers how to do it, get three answers. I should concede mksj has more expertise in this area.

I do have the 3M corporate safety philosophy on Estop. This circuit must kill the machine NO MATTER WHAT. Some idiot mis-wires or programs something, the machine still dies. Yep, this concept just lets the machine coast to stop on E-stop but you cannot do anything program wise to have it not stop. With this concept Estop is only for an emergency - never push it for normal operation. Then set the Estop when you are done. Now your kid etc. is unlikely to accidently start it up.
Yes I have always been in line with thinking Estop is exactly that it kills everything including power in this instance not only to stop rotation but also kill electricity before it kills you I case of electric shock.In the case of emergency you can't always have everything so best scenario is to totally isolate the equipment .
In the picture attached I see the common forward ,reverse , reset connections but what are the others rst spl spm sph below the forward revers conections
 

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Moper361

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Im Feeling rather helpless and stupid i have been reading all the input but my brain is in overload trying to picture wires etc from a conversation in text.Soi came up with this drawing of what my conception is It might be totaly stupid and unpractical but im all for simplicity rather than wires overflowing out of my lathe like spagetti. I know there are other options but this is a start .Will it work and if not what would i need to change in laymans terms please im electricaly thick haha
 

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markba633csi

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I'm not sure if you really need a separate contactor- I thought most VFDs have internal latching logic for start, stop, etc
You just provide momentary buttons to the corresponding inputs-?
mark
 
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mksj

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You want some form of interlock so the machine will not start if you reset the E-Stop or put the cover on and the machine is in the forward or reverse run mode. A bit difficult in this scenario because you do not know what the switches are wired too. I typically use a 2 pole latching relay that acts after the E-Stop. The E-Stop (and other interlocks like the cover switch) powers the latching interlock relay either via a neutral stop position in the run direction selector and/or via a NO run button (i.e. it provides power to the 2 pole relay so it energizes and latches). One side of the relay activates the latch power, the other side makes a connection to the VFD run inputs.
 

markba633csi

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Ah OK
Did you follow that Moper? Inside your contactor block you would have a pair of poles, one for the latching function, the other one for the enable line
Stop button drops out the contactor and shuts the system down
Draw that out showing the 2 poles rather than just a box, it'll make sense
MKSJ do you use a 110 volt contactor or a low volt one w/xfmr?
 
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markba633csi

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Here is a beginning: (contact closure goes to forward/reverse switch and VFD inputs)
2polelatchckt.jpeg(ignore the numbers)
 

Moper361

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Ah OK
Did you follow that Moper? Inside your contactor block you would have a pair of poles, one for the latching function, the other one for the enable line
Stop button drops out the contactor and shuts the system down
Draw that out showing the 2 poles rather than just a box, it'll make sense
MKSJ do you use a 110 volt contactor or a low volt one w/xfmr?
Yes have been checking contactors out this is as i the lines i was thinking along .So this pretty much confirms its thank you .
 

Moper361

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Thanks for the input so far .I have also been checking on both my lathe motor and my drill press motor and it seems that both can be configures to run 220volt 3 phase as required .So i guess my next step is to buy some vfds .I am looking at the mitsubishi fr-d720s-2.2k units .These actualy use 24volt signal inputs and i believe they allready have a start function built in .My plan for the lathe is to actually remove the front control panel and forward reverse drum switch completely just leaving me the 2 wires for existing safety switches and 3 motor wires. I will the fabricate a new control pane door and rewire with all new switches etc .This way if i ever want to chang lathe back to original i have the panel with all switch gear there ready to go .
 

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mksj

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Given the age of the machines and motors, and for what you are going to pay for 2 VFD's have you considered an RPC? You can use a VFD with an older motor but you need to keep the carrier frequency lower, around 2-4kHz so a bit of a whine when using them. Mitsubishi are not a common VFD in hobby circles, all though a few people have used them. I would recommend going with the Teco drives, a little easier to configure. If you are looking for drives with a removal front panel and also the ability to handle an external braking resistor (should be used with the lathe) then I would look at the Teco E-510 series, something like the EE510-201-H-U (1 Hp), EE510-202-H-U (2Hp) motor. They are a little less then say the Hitachi WJ200 and the front removal panel is nice. Check with the dealer, as you may need an extension cable and not all versions have a removable front panel. Wolf Automation has better tech. support, price wise very close. I can look into suggested program parameters, but I feel an RPC may be an easier and maybe less expensive at the end of the day.
1Hp
2Hp

As far as relays/mini contactors and auxiliary power for the lathe latch, I typically use a small 24VDC power supply in the range of 50-75W. These run off of any input power from 100-240VAC, and are inexpensive. I use the MeanWell power supplies, or the Rhino from Automation Direct. The relay/mini contactor only takes a small amount of power, but you can run 24V LED lighting, tachs, etc. I do not use AC relays, as the latch can drop out in some cases. The relay plugs into a base and you wire up the base. On the mill, I would juts use the remote panel. I get most of my supplies from Automation Direct.
 

Moper361

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Given the age of the machines and motors, and for what you are going to pay for 2 VFD's have you considered an RPC? You can use a VFD with an older motor but you need to keep the carrier frequency lower, around 2-4kHz so a bit of a whine when using them. Mitsubishi are not a common VFD in hobby circles, all though a few people have used them. I would recommend going with the Teco drives, a little easier to configure. If you are looking for drives with a removal front panel and also the ability to handle an external braking resistor (should be used with the lathe) then I would look at the Teco E-510 series, something like the EE510-201-H-U (1 Hp), EE510-202-H-U (2Hp) motor. They are a little less then say the Hitachi WJ200 and the front removal panel is nice. Check with the dealer, as you may need an extension cable and not all versions have a removable front panel. Wolf Automation has better tech. support, price wise very close. I can look into suggested program parameters, but I feel an RPC may be an easier and maybe less expensive at the end of the day.
1Hp
2Hp

As far as relays/mini contactors and auxiliary power for the lathe latch, I typically use a small 24VDC power supply in the range of 50-75W. These run off of any input power from 100-240VAC, and are inexpensive. I use the MeanWell power supplies, or the Rhino from Automation Direct. The relay/mini contactor only takes a small amount of power, but you can run 24V LED lighting, tachs, etc. I do not use AC relays, as the latch can drop out in some cases. The relay plugs into a base and you wire up the base. On the mill, I would juts use the remote panel. I get most of my supplies from Automation Direct.
I hear what you say about RPC and have browsed over them a bit online but have had no experience with them .In saying this from what i understand is you would have the ability to just plug existing units into it and off you go however you would lack the option of variable speed .braking and also a RPC would need leads running around the floor to reach to it were as a vfd diectly on machine is just plug into a wall socket .
Given yes the lathe and mill are quite old The Lathe and drill will see some use but not constant only be used as general hobby and not pushed hard .Im all new to the vfd as you can tell but was in the mind of thinking if i can get a couple of years out of the old motors even if there is a little noise id be happy .

I was only looking at mitsubishi as it is easily available in thailand and i have friends with a drilling company and they have had good results from the mitsu units .I was also looking at the same teco e510 as you suggested and yes have to agree its a good unit to id be happy to use it if available in thailand at a reasonable price .maybe there are some advantages of rpc that im not aware of and would like to know if im missing something or if someone can enlighten me
Thanks for the help mksj
 

markba633csi

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Hi Moper yes definitely buy what you can find locally if it is Mitsubishi that's great
 

Moper361

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Well thanks everyone for the help and input .Over the last three weeks or so i have managed to build up my new control panel as i plan to keep old switch gear etc complete so made a whole new panel.
I have had it all connected up to a spare motor i have and after doing some basic settings everything is working as planned running nice smmoth and quiet .all my forward reverse switching and foot pedal work well along with tachometer etc .I just need to get it set up in lathe now and then do a little more fine tuning .
I purchased the huanyang 1.5kw vfd and mitsubishi 1hp motor .
 

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