AKN
Master of Disaster
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So am I.
- Thread starter James87
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Hood
I am obsessed.
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You said.
Better tell that to almost every 3 phase induction motor manufacturer as they have been giving us false information for many years and I am guessing that could be very dangerous. For example this is off a new ATB motor I have here, it is clearly putting me at danger as it is telling me if I want to connect Star I only need 3 phases.
Better tell that to almost every 3 phase induction motor manufacturer as they have been giving us false information for many years and I am guessing that could be very dangerous. For example this is off a new ATB motor I have here, it is clearly putting me at danger as it is telling me if I want to connect Star I only need 3 phases.
AKN
Master of Disaster
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The connection to the mains where there in no neutral connection is a delta connection. The internal configuration of the machine can be delta or star with an internal star point Does not change this. It is only a star connected load on the mains if a neutral connection is made between the star point and the supply.
daleyd
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You should really put up a picture or an example of this as in 20 odd years of working with 3 phase motors I can not think of one example where a neutral was used. Obviously excepting your 3 aircraft example but that’s not really relevant to this discussion.
If you are talking 3 phase loads like heaters/transformers then yes - motors - no.
AKN
Master of Disaster
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From the point of view of the mains supply:-
A 3 phase heater with no neutral connection is a delta connected load. Yes or No?
A 3 phase heater with a neutral connection is a star connected load. Yes or No?
AKN
Master of Disaster
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Why does it not apply to motors?
A 3 phase motor with no neutral connection is just a delta connected load from the point of view of the mains supply, the same as the heater.
daleyd
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Because as they rotate the current returns through the other windings - static loads can’t do that so they (sometimes, not always) need a neutral. Like I said if you can find me 1 example of using a neutral in a standard 3 phase squirrel cage induction motor then I’ll be surprised (notwithstanding weird aircraft/military applications)
brightspark
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on a 3 phase genny the star point in the center is the neutral take off .a 3 phase induction motor is just 3 phase no neutral on either high voltage or low 415v or 240v dual voltage
Well that escalated quickly
So it runs, there is no neutral, just 3 live and an earth, by the colours we think it may be 3 core single phase cable with earth?
I sue I now have us that it builds pressure to 10 bar then the keeps running constantly and vents excess pressure back through the hole pictured
Fix one issue to gain another
So it runs, there is no neutral, just 3 live and an earth, by the colours we think it may be 3 core single phase cable with earth?
I sue I now have us that it builds pressure to 10 bar then the keeps running constantly and vents excess pressure back through the hole pictured
Fix one issue to gain another
daleyd
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Sorry to sidetrack thread but I just checked the manual from 3 phase thyristor products the company I work for manufacture (I’m a bit rusty having not done a lot with them the last few years so wasn’t confident enough to say without checking) and you can get load configurations (heaters/transformers - not motors!) of star or delta both with or without a neutral connection - so the idea that the presence of a neutral is indicative of a certain type of connection is wrong, even without it being a motor.
rotatory screw compressor...
it looks like it just has start stop and emergency stop buttons.... any other options there?
some of them are like hydrovanes where you have an option to keep them running 24/7 and they just vent off extra pressure / don;t make any extra pressure
That's right, just stop start and emergency stop.
My understanding is that the solenoid pictured senses when pressure setting is reached and ramps.pressure down and vents for x amount of time then switches the unit off until the lower limit of the pressure switch is reached, then turns it back on.
Surely it shouldn't run 24/7
daleyd
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Don’t know about Fiac ones particularly but the other ones I’ve seen in factories don’t run continuously , they cut in and out according to pressure demand. Can you get a manual for it? Might take a bit of Googling but should be available from somewhere??
Are there any circuit boards in there or is it all discrete components?? If it’s discrete components then you should be able to work out what’s going on, if a circuit board then you would need some sort of info as to what it’s expecting to see in terms of inputs and outputs.
mtt.tr
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The correct operations it should start up call the load solenoid
Start to build pressure to 10bar
Shuts of the load solenoid
Then run on for a period with a small amount of pressure in the separator
Until it either call for air or switches of on the timer
The run on is important to cooling the screws and bringing down the pressure in the air end otherwise they can spit out oil
Thanks, glad I'm.not loosing my marbles, I'll give it
Another look today with the control board out and see if I can test the timer. It may be I've just not left it running for long enough (if the timer is adjustable)
Yep full board, probably abit above my pay grade
