Question about vacs????

Wintoh

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Joined
Mar 1, 2014
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18
My friend is debating buying a fein extractor he has a mixture of 110 and 240v tools but wants to buy a 240v vac will the vac still fire up on auto with the transformer plugged into the vac using a 110v tool? I know this isn't a question about a festool extractor but I'm pretty sure the internals would work same between the different company's and wondering if anyone on here has any experience using this setup? He was told buy one guy that the power the transformer draws would make the vac the vac run continuously in auto mode without the tool being turned on is this true?????
 
Yes it will run all the time if you plug a transformer into it, that's my guess any way I've never tried it.
 
Yes, it is true, the Vac will run continuously as soon as you plug the transformer into the PTO on the vac.

I only have a couple of 110v tools, one of which is a sander. I plugged the sander into the transformer and then plugged the transformer into the my 240v CT Vac. The Vac fired up straight away before I even touched the 110v Sander.....!!!!

Tim.
 
There was once my Fein did not auto turn OFF when I switched of the tool.
I switched the vac off and turn back to auto and immediately the vacuum started.
Even after I unplugged the tool, the vac still turn on immediately once I set it to auto.

I unscrewed the plug, take a look but could see nothing out of the ordinary.
Strangely, after that, it goes back to normal.
Anyone experienced that before?
 
It depends on the triggering threshold of the vacuum, but it should still function in auto mode with a transformer. When you first plug the transformer in, there will be an inrush current to build the magnetic field around the transformer windings. This will trigger the vacuum to start. However, once this magnetic field is created, there will be very little current drawn by the unloaded transformer, and the vacuum should shut back off until a tool is turned on.

I do have a portable transformer, and I did confirm this with my Festool vac. However, that's not to say it will always work with all vacs and all transformers. So your mileage may vary. I put an ammeter on my transformer, and it peaked at 63 mA and then tapered off to 0 amps in about 4 seconds. The vac only ran for a couple of seconds. I believe the Festool vacs have a triggering threshold of about 40 mA, but I cannot confirm this at the moment.

The principle is that transformers are very efficient concepts, with real-life transformers behaving very close to the ideal transformer laws. The transformer law states that the current on the input will be proportional to the current at the output, and that includes going all the way down to zero amps. So when there is no draw at the output, there will be virtually no amperage at the input.
 
The instance I described above was with a 2002 Festool  CT11E and a 2002 110v Metabo 150mm Orbital sander.

I don't know the manufacturer of the 110v transformer that I have, or its age exactly but I think it must be at least 15 years old.

All these "Tools" are a few years old now, obviously!. Perhaps the later model power Tools/Vac/Transformer have different characteristics and therefore would perform differently, but using the set-up as I described above, the Vac continued to run indefinitely. It did not shut down after a few seconds.

I now have a new (4 months old) CT26 in my workshop, perhaps I'll try that on the Transformer and see if it performs differently.

Tim.
 
I have not tried it with my CT but, from an electrical engineering perspective, I am with Rick on this one but it does need to be properly tested.

Peter
 
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