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Jet Chip Extractor and Household Power Supply - Tripping

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wcndave

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I have a Jet DC1100A Extractor which is hooked up to workshop power supply, which has a separate fuseboard from rest of the house, although they then go to a common outside fuse box.

My power supply is 6kw (which is double the standard amount here in Italy....)

When I have been working, say on table saw, with chip extractor on, and the table saw has stopped, I usually wait a few seconds, then turn off extractor.

It then spins down slowly, and at the very end makes a click noise as though something disengages in the motor.

60% of the time, at the moment of the "click", the fuse trips on my workshop box, and I lose power.

I feel there may be some back induction or something, however I am not an electrical expert, any thoughts on what might be occuring?

Powering up /down the table saw has no such effect.

Thanks, and HNY!
 

sunnybob

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The centrifugal switch on the motor is cutting out (thats the click you can hear), and the tiny spark it produces is tripping your surge protector / elcb / rcd. Lots of names for slightly different things that all have the same purpose. the unit thinks the spark is the start of a short circuit so trips.
It possible to replace the unit with a slower acting trip, but in Italy you would need to consult your local electrician.

Its not a fault, just a mismatch.
 

samhay

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Has it always done this?
If not, you may have a snubber (capacitor) that's failed open.
 

wcndave

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samhay":dxg0mx60 said:
Has it always done this?
If not, you may have a snubber (capacitor) that's failed open.
This hasn't always happened, I don't think, perhaps last year. Any idea how I would verify /fix

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shipbadger

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I have the same extractor and it trips my supply at the other end of use, at the beginning. It happens when I press the start quickly. If I let my finger dwell for a moment all is well. From comments above I assume this is the result of sparking. It's always done it but a caveat, I did buy it second hand.
 

wcndave

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Interesting. With a remote of course, I can't "dwell"... however it's definitely not something that happened in the first couple of years.
 

wcndave

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sunnybob":ha81wvkq said:
The centrifugal switch on the motor is cutting out (thats the click you can hear), and the tiny spark it produces is tripping your surge protector / elcb / rcd. Lots of names for slightly different things that all have the same purpose. the unit thinks the spark is the start of a short circuit so trips.
It possible to replace the unit with a slower acting trip, but in Italy you would need to consult your local electrician.

Its not a fault, just a mismatch.
Sorry, your reply was superseded by a later one, hadn't seen it.

What doesn't quite match up with your description is that it's started happening recently (6 months) and I have had it in the same place for 5 years...

I wonder if plugging through a surge protector would help?
 

sunnybob

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Modern safety circuits are getting more sensitive all the time, which is a good thing as it protects people.
But modern machines are getting more and more power hungry. The new brushless motors for example, are much more economical when they are running, but to achieve that they require an extra "kick start" to get them running. That power surge can sometimes be many times the rated consumption of the machine. It only lasts for tiny fractions of a second, but if your trip circuit (there are many names and types) is very sensitive, it will see that power surge as the start of a short circuit and trip out.
The mention of it happening when not pressing the button firmly is the same. Fluttering the button introduces the spark
Thats the start up problem.
The original post was on shutdown, but many motors now have a mechanical centrifugal switch on the motor, which, when it gets older, or dusty, can produce a spark as it opens. This spark is again seen as a short circuit and off it goes. A good dust off and clean under the covers (with the power OFF of course) might solve your problem.

I'm 10 years out of date now, but was getting a lot of this problem on the big machines I worked on. Its called "nuisance tripping" because there is no real reason for it. Getting a sparky to replace the standard ultra sensitive trip with a slightly less sensitive one, cured the problem every time.
 

wcndave

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sunnybob":1ewg5a9f said:
Modern safety circuits are getting more sensitive all the time, which is a good thing as it protects people.
But modern machines are getting more and more power hungry.
Yes, on start up, my tablesaw often blows the main house fuse if the dishwasher or oven or cooker is on.... Not helped by having only 6kw. I don't know how the "standard normal" people here cope, with just 3kw.

When I told my electrician I wanted 6, he raised his eyebrows and asked if I was planning to run a factory.

He didn't believe that in the UK we have about 10-15kw as standard.
 

sunnybob

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0pen door, leaning against.....

I had a hell of a fight with the electricity authority of Cyprus, they considered a 40 amp main breaker as more than adequate for a 4 bed house. The plans had ONE electric socket in each room, with I think FOUR in the kitchen. I had to redraw the plans myself.
Even employing a local sparky (which got me round many a problem :shock: (hammer) ) I still only managed to get 60 amp. I would have had to go three phase to get any more.

When they came to inspect the place before "allowing " me to pay them , I had to lock up the garage and not mention there was electric in there. :roll: :roll: :lol:
 

wcndave

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So 10kw normal there... I could only dream of that.... and I have to pay a premium rate on all power because I have the massive 6kw.... I see why you're sunny now ;-)
 

sunnybob

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The first 4 years here I was on a "temporary" supply. That was basicaly a 600 ft extension lead across the building site. Many was the night I had to walk the length of the building site to reset the breaker. Sometimes it would trip while under the shower.
Those days werent so sunny (hammer)
But I was better off than my neighbours. 2 houses shared a single cable. They had to stagger evening meals so that they didnt have two ovens on at the same time.

These last few years have been bliss. 8) 8) even if I did have to pay for the mains underground cable myself. :roll: :roll:
 

wcndave

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So, back to business. I opened up the starter unit, and it was not really dusty at all. Gave it a good clean, but problem persists.

(see attachment)

Did you mean to open the motor housing, or something else?
I can of course ask for a less sensitive fuse, however as this problem is "new", something must have changed somewhere...

:?
 

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guineafowl21

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Can you specify exactly what is tripping? RCD or MCB?

It looks like you have a double pole switch there, so once switched off, the motor’s centrifugal switch should be completely isolated and unable to cause a trip. It’s possible the start switch is failing and sometimes linked across on one pole and is tripping due to an imbalance on shutdown. A new DOL switch should cure it.

Another thing to try is blow out the motor with compressed air.
 

wcndave

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I will check what I have regarding the trip switches.

For the start switch and isolation, I have this plugged into a remote controlled switch, and therefore the start switch is always on.

I will try a few times trying to switch off at the machine, to further isolate, however I really want to be able to use this with the remote.
 

guineafowl21

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That’s an MCB and RCD in one package, so you can’t tell what type of fault is occurring. It is a ‘C’ trip curve rather than the usual domestic ‘B’ type, so most likely an earth leakage fault.

What’s inside the remote switch? Single pole/double pole? Take it out of the equation and see if the fault persists.
 
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