Wiring Dust Extractor with Variable Speed lathe ?

[myturn]

I have a variable speed lathe (with NVR on/off and speed control in a moveable control unit) and dust extractor with NVR on/off. The extractor is dedicated to the lathe and only used with the lathe. The lathe also has a separate Emergency Power Off button that cuts all power to the lathe.

I would like to have the lathe turn on the extractor when I start the lathe and turn off the extractor when I stop the lathe.

I've tried a Record Power WVE002 AUTO SWITCH and with the lathe in a TOOL socket and the extractor in the EXTRACTOR socket the lathe will turn on the extractor (using the NVR's Start button) but won't turn it off when I stop the lathe using the NVR's Stop button. If I hit the lathe's Emergency Power Off button it WILL stop the extractor.

I gather that variable speed controllers such as those fitted to lathes don't work too well with the WVE002 (my previous lathe didn't work with it at all). The WVE002 works fine with other tools like router and bandsaw etc.

Does anyone have any ideas as to how I could achieve the starting and stopping of the extractor in unison with the starting and stopping of the lathe without having to use the Emergency Power Off?

I intend to replace the NVR on the extractor with an ordinary ON/OFF switch as I realise that will be necessary, but how to get the lathe to then control the starting and stopping of it?

Wireless would be nice (I looked at the X10 range of modules but couldn't see how they would work) but I'm quite prepared to do some extra wiring and/or modification to existing wiring.

thanks for any suggestions.

 

[9fingers]

A lot depends on the type of NVR on both the lathe and the dust collector.
Can you post a photo of each please.
If you can't easily post a photo then read my motor paper and quote the figure number of the NVRs that most closely resemble your machines.
Bob

 

[myturn]

Hi Bob,

The lathe has one of these on, the photo is from an Axminster lathe and mine is a Killinger KM1400SE but it's exactly the same box even including the German labelling. The lathe motor is a 3-phase 750W.

The extractor has one of these. I've already opened it to see what I need to do to replace it with an on/off rocker as that was what I am assuming I will need to do. Is it a simple matter of joining motor neutral to supply neutral then putting the rocker between motor live and supply live?

 

[9fingers]

I would not suggest connecting the lathe and DC in the manner you suggest.
I suspect that the NVR function on the lathe is implemented in the software of the inverter. This is a standard way of doing it.
Some inverters have a logic output that changes when the motor is running interfering with this without intimate knowledge of the inverter would be undesirable.
I would bypass the NVR on your dust collect and use a remote control socket to switch it on from a handset in your pocket or near the lathe.
Toolstation sell a very reasonable one that I have recommended to others for this sort of application.
part number71401 for £16.98 and free delivery. The pack contains 3 switches leaving two others for use round the workshop.

hth

Bob

 

[myturn]

Thanks for the info Bob.

I already have a set of remote control sockets similar to the ones you describe, from Maplins, but I would really like to automate the process.

I've checked inside the lathe's control box and you are quite right of course, there are no relays or anything in there and the on/off buttons are just push-button switches.

Could I not piggy-back something off these switches?

Alternatively I've seen a control unit from Axminster, rather expensive but If there were no other (cheaper) solution would that do what I want? It seems to use passive sensing without the need for any electrical connections that might interfere with the inverter.

 

[9fingers]

Absolutely NOT. Without the full inverter manual it would be madness to interfere with the wiring. Typically the control supply from an inverter for such switches is only rated for a few mA

The only hope would be to persuade the manufacturer to tell you who inverters they use but it could be a special and you could still risk damage to an expensive item.

I've no experience with that axi unit but be aware that the drive signals from an inverter to a motor are typically 4 to 16kHz pulses which may not be detected by what ever pick ups they use.
If you really want to spend that sort of money, then see if Axi will allow you to return it in the even that it does not work

Sorry to pour cold water on your aspirations

Bob

 

[myturn]

Absolutely NOT. Without the full inverter manual it would be madness to interfere with the wiring. Typically the control supply from an inverter for such switches is only rated for a few mA

Ok, how about replacing the push buttons with double-pole buttons so one pole would work the inverter as normal and the other could activate something else to control the extractor? Not my preferred solution but still feasible? :duno:

The Axi control unit is described as sensing the magnetic field from a powered motor, is that not different to the pulses from the inverter and thereby more likely to work?

I will ask them but I'd rather not spend that amount of money if there is (and I'm sure there is) a cheaper solution.

I'm sure there must be a way to do this, there is no such thing as "can't" in my book, only "I don't know how".

Pouring cold water is all part of the process of elimination, a solution will eventually arise :idea:

 

[CHJ]

Why on earth would you wish to configure a setup so that the extractor can only run when the lathe is rotating ?
30-40 % of my sanding is done with lathe stationary and the extractor also helps remove any applied finish solvent fumes from my immediate location.

 

[9fingers]

I agree with a "can do" attitude and I would do it myself but with so may unknowns I'm not prepared to take the risk of saying 'do it this way or that way' remotely.
The magnetic field from an inverter driven motor contains high frequency spikes. I have no way of knowing how the axi sensor will react to these.
Changing the buttons for double pole ones is not a bad idea but I would use a low voltage DC supply with the other poles and not feed mains into them to avoid possible inverter problems.

Bob

 

[myturn]

Why on earth would you wish to configure a setup so that the extractor can only run when the lathe is rotating ?
30-40 % of my sanding is done with lathe stationary and the extractor also helps remove any applied finish solvent fumes from my immediate location.

I don't think I said I wanted it to run ONLY when the lathe is running, perhaps that was not clear.
I would fit an override to enable the extractor to run without the lathe, but as 93% of my sanding is done with the lathe turning that is my ain requirement.

Solvent fumes are not a problem, they add to the fun :mrgreen:

I agree with a "can do" attitude and I would do it myself but with so may unknowns I'm not prepared to take the risk of saying 'do it this way or that way' remotely.
The magnetic field from an inverter driven motor contains high frequency spikes. I have no way of knowing how the axi sensor will react to these.
Changing the buttons for double pole ones is not a bad idea but I would use a low voltage DC supply with the other poles and not feed mains into them to avoid possible inverter problems.
Bob

Thanks Bob for the advice Bob, looking at the wiring in the control box it's all ultra-thin (smaller than telephone wire) and I wouldn't put any mains in there. I've still not excluded the X10 solution but I don't fully understand how it works nor what its limitations are yet.

It's occurred to me that I might be able to adapt the remote-control handset unit for the Maplin remote control power sockets having replaced the lathe's NVR buttons with DP ones. The spare pole could work the handset circuit's on/off switches. The advantage of that is that I could power off the lathe by its main "Emergency" stop button and still work the extractor using the lathe's remote NVR box's buttons.
This would be neat if it works as it would be wireless and require no special override switch to start the extractor with the lathe stopped.

At least you've warned my of the possible pitfalls for which I am grateful and I'll now continue in my search for a solution which I'll post up WHEN I find it.

 

[chipmunk]

Hi Mick,
If you fancy a challenge, have you thought of using a power relay such as one of the ones here?....

http://www.maplin.co.uk/components/relays/power-relays

10A contacts combined with a 240V coil could give you the double pole switching you need for your dust-ex and with a relay base you can get screw terminals that make wiring pretty easy. You then just need somewhere with a switched 240V to energize the coil from. This could be the motor windings themselves perhaps as a last resort. Although the AC frequency may be a bit slow with variable speed this ought to be ok. Perhaps you'd need to test it to see if the coil gets warm after a while on the slowest speed :wink:

HTH
Jon