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Need help with this speed controller!!!

MaxHeadRoom78

Well-Known Member
#22
i think the OP has his plate full already, bringing in 3-phase into the discussion will only tend to confuse things further. this discussion has been about single-phase and "split phase" house wiring, and whether he can use his TRIAC controller on a normal single phase outlet.
The reason I used the comparison was to indicate the fact that there is nothing special about a Neutral, apart from being referenced to Earth GND.
The neutral issue was where he appeared to be confused over.
The guy's that buy a VFD to run it off 1ph 240v in N.A. often have the same questions.
Max.
 
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unclejed613

Well-Known Member
Most Helpful Member
#23
I've never seen a diac that high, they all seem about the same voltage (about 30V?), and work fine at 120 or 240.
i've not done much with TRIACS except repairing dimmers occasionally, and usually dimmers are so cheap it makes more sense to replace the whole dimmer.
 

gophert

Well-Known Member
Most Helpful Member
#24
i've not done much with TRIACS except repairing dimmers occasionally, and usually dimmers are so cheap it makes more sense to replace the whole dimmer.
Except when it is integrated into a switch/dimmer that is built on a pcb that fits into a custom space in a lamp.
 
#25
AC mains normally works on 1 wire, the second wire is not the carrier, its a neutral conductor with the generator for reducing the losses. 230VAC are used for Europe and other countries.

You can get a step-up transformer which will make the voltage higher.
 

gophert

Well-Known Member
Most Helpful Member
#26
AC mains normally works on 1 wire, the second wire is not the carrier, its a neutral conductor with the generator for reducing the losses. 230VAC are used for Europe and other countries.

You can get a step-up transformer which will make the voltage higher.

One wire! What?!!

It is called a circuit because...?
 
#27
This is AC not DC....... don't be blaming if you don't know!

You can always connect your device to a ground which is an ambiguous term and skip the neutral or all wires from the mains except the phase.
 
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gophert

Well-Known Member
Most Helpful Member
#28
This is AC not DC....... don't be blaming if you don't know!

You can always connect your device to a ground which is an ambiguous term and skip the neutral or all wires from the mains except the phase.
Current must flow to compete the circuit so the neutral wire must be the same or fatter wire to safely return current to the generating source (or the transformer let by proxy). The ground connection is simply to reference the circuit to a standard voltage so the 120 does not float to many thousands of volts above the intended plug voltage - it is not (NOT) intended to carry any current from the circuit. Your view of "one wire" is dangerous.
 
#29
Not true! Thtats the exact right view thats used. The neutral or "0" wire is always the thinnest because the manufacturer does not want to pay, in fact a lot of the problems that occur are because the wire breaks easily and needs to be fixed. The grounding is mandatory and can be used at many places instead of a neutral wire, like I said before the neutral wire is only for reducing the losses, its not really needed.
 

alec_t

Well-Known Member
Most Helpful Member
#30

MaxHeadRoom78

Well-Known Member
#31
AC mains normally works on 1 wire, the second wire is not the carrier, its a neutral conductor with the generator for reducing the losses. 230VAC are used for Europe and other countries.

.
In countries such as UK etc the neutral is the star point of a 3ph transformers and carries the same current as the 230v phase.
In N.A., the N is a centre tap of a 1ph transformer and must be capable of carrying the current of either live conductor.
In the case of a 120v or 230v transformer secondary where a neutral is required, it is arbitrary which secondary terminal is used and connected to earth ground.
Where a neutral exists, using ground as a conductor is forbidden.
Max.
 
#32
It might be for you, but not for me. You have 5 wires(3 phases, 1 neutral, 1 ground), The neutral and ground are both connected, if the neutral brakes you will have some spikes but your house will keep running.

And thats an iron rulle of AC voltage, only the phase is the carrier and the neutral wire is not needed.
 
#33
https://www.quora.com/Why-do-we-need-neutral-wire

And its not stupid if you know what you are doing.

There seem to be a lot of misunderstandings about AC transfer. I had an argument about this in another topic, I don't want to argue again.

EDIT:
https://www.quora.com/Is-it-ok-to-use-earth-or-ground-as-a-neutral-in-AC


However the ground wire is used in a lot of cases, and there is no way for it not to work, because when the neutral wire breaks, which happens a lot here, the grounding must take all the current. At the end the current flows through the lowest resistance, if the ground resistance is small or as you would say the potential is enough, then current will flow.
 
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MaxHeadRoom78

Well-Known Member
#34
It might be for you, but not for me. You have 5 wires(3 phases, 1 neutral, 1 ground), The neutral and ground are both connected, if the neutral brakes you will have some spikes but your house will keep running.

And thats an iron rulle of AC voltage, only the phase is the carrier and the neutral wire is not needed.
Where are you located, obviously you are running 1ph from two phases!!
There is no 3ph residential here or in most jurisdictions.
The star neutral condition with one phase is used in UK and Australia.
No neutral, no power.
Max.
 

JimB

Super Moderator
Most Helpful Member
#36
AC mains normally works on 1 wire, the second wire is not the carrier, its a neutral conductor with the generator for reducing the losses. 230VAC are used for Europe and other countries.
Are you getting confused with Single Wire Earth Return (SWER) electrical distribution systems?
In an SWER system the single line conductor is at several thousand volts, connects to a transformer primary, the other side of the primary connects to earth. The secondary side of the transformer provides the low voltage (two wires) to the customer.
Such systems are used in Iceland.

You can always connect your device to a ground which is an ambiguous term and skip the neutral or all wires from the mains except the phase.
There is a couple of words for that, stupid and illegal.

The neutral or "0" wire is always the thinnest because the manufacturer does not want to pay,
Are you confusing with a three phase balanced system?
In a three phase system with a balanced load, the net current in the neutral conductor is zero.
When the load is unbalanced, there will be a current flowing in the neutral.

And thats an iron rulle of AC voltage, only the phase is the carrier and the neutral wire is not needed.
I think that I just tried to explain that.

https://www.quora.com/Why-do-we-need-neutral-wire

And its not stupid if you know what you are doing.

There seem to be a lot of misunderstandings about AC transfer. I had an argument about this in another topic, I don't want to argue again.

EDIT:
https://www.quora.com/Is-it-ok-to-use-earth-or-ground-as-a-neutral-in-AC


However the ground wire is used in a lot of cases, and there is no way for it not to work, because when the neutral wire breaks, which happens a lot here, the grounding must take all the current. At the end the current flows through the lowest resistance, if the ground resistance is small or as you would say the potential is enough, then current will flow.
You seem to be mis-understanding those two references.
They are agreeing with the rest of us here.

JimB
 

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