Thread: Making sure your DC is on

I've mentioned in a few posts how these things have saved me from a face full of dust, on both the Router table and Band saw. It's been around 2 months since I was in the wood workshop, I had a need to square a slab of timber for SHMBO, I decided to test a dust sensor at the same time. Turned on the DC, check gates, power to the Band saw, pressed the start button - nothing. I know the sound of the DC system and I could hear that air flow was down a bit, suction felt lower than normal as well. Went around and checked the other blast gates were all closed, double checked again, SWMBO followed me checking one last time before I checked the Vacuum switch, as she walked past a 100mm hose hanging on the side wall she heard a noise, the hose is used for the Drill press when needed but capped off when not in use, the $%^& cap had somehow fallen out.

That's all it took, pressed start and the band saw was running. That's enough to make a difference between "no dust" and "some dust" and I'd rather know before I start working then a few minutes later when the sinus reaction starts and takes a couple of hours to subside. It's another one of those things you think you won't really use, but in my case,I wouldn't be without them.

Here's the first of two singe phase versions of the DC vacuum monitor switch I said I would show.

As usual check with your sparky before applying power.

This one uses a 5 pin NoVolt (NV) switch and the parts needed are
- 5 pin No Volt switch
- vacuum/pressure switch
- IP rated box
- enough vacuum hose
- 10A extension cord.

IMG_2507.jpg

This shows "in" and "out" mains power going to/from the NV switch.

The vacuum switch (P) is wired in series with Active out side of the NV switch and the electromagnetic coil connect (C)

IMG_2506.jpg

Here with the cover on showing the exposed pressure adjustment screw (A)
The end of the brown rubber tube (J) is connected to the drip irrigation fitting screwed into the ducting in between the machine and its blast gate
IMG_2508.jpg

This version uses an extension cord for use in between a machine and a GPO, but ideally you could also replace a machine switch with this sort of setup since this would save triggering two switches to start a machine. I have set this up like this to show as a demo to mens sheds.

I got my NV switch switches from eBay - the 5 pin versions cost about $15.
Watch out because some of the eBay suppliers are selling NV switches for $8 but these are usually the 4 pin models.
Some suppliers even show 5 pin version in their photos but are actually selling the 4 pin versions

If you have have 4 pin versions on your machine you can still use them via a relay and I will build one of those and show this WIGRTI.

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Do you have a link to the JCZ3B NV switch? A search on eBay gives an "ended" post and all the rest K type are as you described; listed as 5 pin but are 4 pin.
Cheers

I bought that switch a few years back and the link I have is also no longer current.

Try searching for the KJD18, it's also a 5 pin NV switch that should do the trick.

e.g. [NEW] 250V 15A KJD18 Switch 5 Pin No-Voltage Release Switch Plastic | eBay

Here is the 4-pin NV Switch plus relay version.

220V coil 220V Relay is before the switch with the relay coil is in series with the Vacuum switch.

The enclosure does not need to be as big as men but I bought a bunch of these boxes on eBay and they were cheaper than I could buy a smaller box for locally.
Also the bigger box helps to show the mens shed blokes how it works.

IMG_2509.jpg

IMG_2510.jpg

The relay is a SS 30A (JQX-30F) 220V relay - these cost about $3.50 on eBay and should be suitable for all 10A machines.

If you already have a 4 pin switch then using these relays ($3.50) is the cheapest solution.
If you have a 5-Pin switch then you don't need the relay.

As usual please get sign off by your sparky.

Yesterday my bulk order of 10 of these vacuum switches turned up.
The first pair of switches took 2 weeks to get here and the bulk order of 10 took 20 days so not too bad.

I've put one of these switches on my Belt sander, lathe and bandsaw as these all have VFDs and only a switch is required for these machines and they are Just 20 minute installs.

The next machine that is going to get the treatment is the Table saw.
The TS will need two vacuum sensing connecting points - one for the OH guard and one for cabinet.
I could connect rubber tubes to these connecting points back to a single vacuum switch and then adjust the vacuum setting on the switch so that unless both are under vacuum the switch would not work but I think it will be easier to use two switches and run wires rather than rubber tubing as follows..
I will put one switch on the cabinet and one on the OH guard up near the ducting for the OH guard and run a cable back from that switch back to the TS cabinet.

My TS power is under floor through a 50 mm PVC pipe so it will easily be able to fit another cable. The wire will go from the OH guard up the OH guard support which is connected to the ceiling along a rafter to the wall, down the wall into the PVC pipe under the floor to the come up under the TS.

The two switches will then be wired in series and as this is a single phase machine with a 4 pin no volt switch it will need a relay as well.

At the mens shed there are 5 machines identified that will get one of these vacuum switches, disc sander, small and large belt sander, drum sander and 14" bandsaw. This will be done by me and the Shed Sparky. The other machines like TS, Thicknesser, jointer, RAS, large BS etc are 3P and some of these are mobile so will need further consideration and I will be getting our shed sparky in on this. The RAS is about to get a VFD so that will be easy enough.

Here's link to the vacuum switches
https://www.aliexpress.com/item/AC20...311.0.0.5iAIJ5

Finally got around to adding vacuum switches to my TS.

The first vacuum switch is on the OH guard
The white cable (See red arrows) connects to the switch inside the box runs up and across the ceiling and down the wall to the 50 mm PVC duct that goes under the floor and comes up under the TS. That PVC duct also carries the main power to the TS
TSOHG1.jpg

The pressure switch has 240V on it so it has to be mounted in an IP rated box which is just Tek screwed to the ducting with the vacuum sensing point being located below the gate valve.

TSOHG2.jpg

On the LHS of the TS I located another box with the second Vacuum switch connected to the cabinet (actually its at the bottom of the sawdust hopper under the saw) just above the gate valve that is under the saw. That gate valve is only used to divert flow to the under router table side duct but it will still detect if any of the other 2 gate valves back along the ducting to the TS cabinet are closed.

The TS has 4 pin NV switch so the vacuum switches are used to switch a 15A conventional relay. I also added a switch (to by pass the Vacuum switches if for some reason I want to operate the TS without the DC.

TSCabinet.jpg


Cost wise, the 2 pressure switches cost a total of $6,relay $3, 2 boxes a total of $20, white cable $15, the 4 cable glands totalled $8, and the switch came off an old heater. It all adds up but I think it's worth it.

I will also add a bypass switch to my lathe vacuum switch because when I make the BMHs, the heating process won't be as effective if there's air flowing over the PVC being heated.

Originally Posted by BobL

At the mens shed there are 5 machines identified that will get one of these vacuum switches, disc sander, small and large belt sander, drum sander and 14" bandsaw. This will be done by me and the Shed Sparky. The other machines like TS, Thicknesser, jointer, RAS, large BS etc are 3P and some of these are mobile so will need further consideration and I will be getting our shed sparky in on this. The RAS is about to get a VFD so that will be easy enough.

Two weeks ago we installed 3 of these switches on the mens shed Band saw, Disc and large belt sander and so far the feed back has been very positive. I don't go into the shed all that often but when I visited on Friday, 2 members told me that they have found the switches have reminded them of how often they used these machine without ensuring DC was switched on and gate valves were open.

The sparky and I have worked out a way of putting them onto 3 Phase machinery by wiring them in series with the contractor/start button.

Are these still working OK?
Do you have a current link?
Thanks
Ian

Originally Posted by Flintlock

Are these still working OK?

Yep all are working fine.

[QOUTE]Do you have a current link?[/QUOTE]

The current link still works.
https://www.aliexpress.com/item/AC20...311.0.0.5iAIJ5

Originally Posted by BobL

Yep all are working fine.

[QOUTE]Do you have a current link?

The current link still works.
https://www.aliexpress.com/item/AC20...311.0.0.5iAIJ5[/QUOTE]

Wow that's a great price....thanks for the link

Originally Posted by ericks2

The current link still works.
https://www.aliexpress.com/item/AC20...311.0.0.5iAIJ5

Wow that's a great price....thanks for the link[/QUOTE]

These types of switches are sold world wide by the millions for central heating control. Every house in north america with central heating uses a couple and this almost certainly explains the price.

Just ordered 10!