How to detect 3phase...

[yusuf]

Hello friends i have a motor pump which runs on 3-phase line...

The problem is the 3-phase line is not available always here...

So i want to design circuit which can turn on the 3-phase motor pump if 3-phase line is available else it will turn off the motor pump..

So i want 3-phase detector circuit to monitor it...


Thanks in advance

yusuf
india

 

[alec_t]

Won't monitoring just one of the phases be sufficient?

 

[Grossel]

Hi.

One really easy solution is to use three regular relays, one per phase. Then connect each relays contacts (that is normally open) in series, wich in turn can activate a contactor.

 

[yusuf]

hi.

One really easy solution is to use three regular relays, one per phase. Then connect each relays contacts (that is normally open) in series, wich in turn can activate a contactor.

can you please provide a circuit ...

 

[yusuf]

won't monitoring just one of the phases be sufficient?

circuit needed ?

 

[MikeMl]

What the previous posters are asking, is it just sufficient to know that a voltage exists on three wires? (e.g. A>limit AND B>limit AND C>limit)
Or are you trying to determine that a specific phase rotation exists? (e.g. A leads B by 120 degrees AND B leads C by 120 degrees AND C leads A by 120 degrees)

 

[dougy83]

Looks very similar to https://www.electro-tech-online.com/threads/3-phase-power-supply-detector.128807/

 

[Grossel]

can you please provide a circuit ...

What you pay me then?
Explanation should be self explained. If you only know the most basic, ie what a relay is and what a series connection is then no more explanation is needed.
If that is not the case (ie. you still not understand) I strongly recomend you to let someone else build it for you.

 

[ccurtis]

I discovered that if one or two phases is dropped, the output of a classic three-phase, half-wave bridge rectifier drops to zero volts periodically, whereas that does not occur when all three phases are present. Using this to advantage, I designed the attached circuit. Rload is energized as long as all three phases are present. (Note: The MUR460 does not have adequate PIV rating margin for the 3-phase voltage used, so beware. Schematic and model is for presentation of a design idea).

 

[yusuf]

Hello guys with the help of you's replies and effort i have designed 3-phase detector circuit...

I have attached the working process in my attachment..

The circuit is working good !

But the problem is :
The 6v power supply to the circuit is given from the one of the charger...
As you know the charger is connected to one of the phase...

Eg :
I have connected the circuit to phase 1(charger 1).
So , if phase 2 or phase 3 disappears then the output pin 1 of cd4012 goes high (turn on the relay).
But it is not necessary that always phase 2 or phase 3 disappears ...
Phase 1 may also disappears..
If phase 1(charger 1) disappears then the whole circuit turns off as the power supply is connected to it..

So guys this is a big probelem..

I want :
The circuit power supply should be connected to the charger like a manner if any phase disappears it should stay on...
It can alternate from one charger to another to have power supply..


Waiting here..........

 

[ccurtis]

I want :
The circuit power supply should be connected to the charger like a manner if any phase disappears it should stay on...
It can alternate from one charger to another to have power supply..

What you need to do then, is to arrange things so that the relay is turned on all the time, except when any one of the chargers goes dead (including the charger that powers the circuit and the relay). Like, say, use an AND gate instead. Then use the N.O. contacts on the relay instead of the N.C. contacts of the relay.

 

[yusuf]

what you need to do then, is to arrange thiings so that the relay is turned on all the time, except when any one of the chargers goes dead (including the charger that powers the circuit and the relay). Like, say, use an and gate instead. Then use the n.c. Contacts on the relay instead of the n.o. Contacts of the relay.

can you provide a simple circuit or visual image of it..

 

[ccurtis]

No drawing necessary. You provided one already. Just change the NAND gate to an AND gate so that your relay is ON when all the phases (inputs are present). Then use the other set of contacts on your relay.

 

[Diver300]

There are phase detection relays that do what you want.

https://in.rsdelivers.com/product/broyce-control/45psr-400vac/phase-sequence-failurerelay-w-led-400vac/3979218.aspx

Those relays will only operate if the three inputs are all present, and the phase rotation is correct.

The suppliers, RS, are charging over twice as much in India for that relay as they are charging in the UK. It is £52.28 + 20% VAT (sales tax) in the UK.

I would have thought that there would be a locally made phase detection relay available in India, especially as it sounds like the mains supply is less reliable there.

 

[yusuf]

no drawing necessary. You provided one already. Just change the nand gate to an and gate so that your relay is on when all the phases (inputs are present). Then use the other set of contacts on your relay.

friend i am not getting you properly..
Please , if you have some time then please draw in paint program.. And attach here

i am waiting here..

 

[yusuf]

there are phase detection relays that do what you want.

https://in.rsdelivers.com/product/broyce-control/45psr-400vac/phase-sequence-failurerelay-w-led-400vac/3979218.aspx

those relays will only operate if the three inputs are all present, and the phase rotation is correct.

The suppliers, rs, are charging over twice as much in india for that relay as they are charging in the uk. It is £52.28 + 20% vat (sales tax) in the uk.

I would have thought that there would be a locally made phase detection relay available in india, especially as it sounds like the mains supply is less reliable there.

friend i want to design it rather then buying...

 

[Grossel]

Um, this is another problem than given in the first post?

Wel, given that you're using some chargers (that you didn't tell about in first post as far I can see) providing the neccesary output that you can detect using cmos gates, I'll recomend that you use a SR latch to make output stay on after you had 3 phase first time. You need to have the ON input to the latch connected to a 3 gated AND (just like the schematic above).

 

[panic mode]

yusuf,

you seem to be quite determined to get this. can you post detailed set of requirements?

for example my understanding is that you:

1. need closed contact when all phases are present
2. need open contact when any phase is missing
3. need open contact if supply power is lost
4. don't care about phase order (this should not matter anyway unless mobile equipment, fixed installations always have same phase order all the time)

can you confirm this?

as others have mentioned before, simplest way to accomplish this is to just use three 230VAC relays (one on each phase) and connect their NO contacts in series.

if you prefer to do it with some electronic circuit, something like this should do:
- each phase is detected individually. note that detection is relative to neutral because line to line input may not turn off if only one of phases is missing.
- inputs are isolated
- presence of each phase is individually indicated
- presence of all phases is indicated (relay closed)
- relay opens if any phase is lost or power to circuit is lost
- phases are usually labelled L1,L2,L3 or R,S,T or A,B,C while neutral is N

 

[panic mode]

using three 230VAC relays wiring would look something like this (here shown NTE relays R14−11A10−240):

 

[yusuf]

you seem to be quite determined to get this. can you post detailed set of requirements?

for example my understanding is that you:

1. need closed contact when all phases are present
2. need open contact when any phase is missing
3. need open contact if supply power is lost
4. don't care about phase order (this should not matter anyway unless mobile equipment, fixed installations always have same phase order all the time)

can you confirm this?

THANK YOU VERYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYY MUCH panic mode !

I HAVE A STARTER WHICH HAS TWO BUTTON ON AND OFF..
ON TO START MOTOR AND OF TO TURN OFF MOTOR..

SO,
I WANT FIRST TO DETECT THE 3-PHASE ..
IF 3-PHASE IS AVAILABLE THEN IT WILL TURN ON THE RELAY 1 TO START THE MOTOR..
IF 3-PHASE DISAPPEAR IN BETWEEN THEN RELAY 2 WILL TURN ON TO TURN OFF THE MOTOR..

RELAY 1 WILL BE CONNECTED IN " MOTOR STARTER ON " TERMINALS..
AND RELAY 2 WILL BE CONNECTED AT " MOTOR STARTER OFF " TERMINALS..

STARTER IS ALSO NAMES AS CONTACTOR...

HELP REQUIRED panic mode !

AND WHAT IS THIS : i HAVE ATTACHED IN MY ATTACHMENT...