Thermal Magnetic Circuit Breaker

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  #1  
Old 01-10-18, 11:57 AM
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Thermal Magnetic Circuit Breaker

Hi all, I'm new here and in all honesty, almost feel a fool asking this question. I live is a country where electrical safety is almost none existent and all home owners undertake poor, for the most, repairs or get Jack the lad to fix something to a sub standard level.

I have very recently replaced a pressure cylinder for the supply of borehole water via a submersible pump. I have no idea which pump is in use or the number of wires or colours. The wiring is very poor and it is my intention to replace. Incorporated into the system is a thermal magnetic circuit breaker as seen below. It is not mounted on a buzz bar and has some terminals used but not all. At the moment there is a wire from a lower terminal that feeds an upper one.

The Thermal Magnetic Circuit Breaker is a GV2ME16 by Schneider-Electric.

My thoughts are that each section between left and right would be isolated from each other and that each of the top electrical terminals, would serve a particular purpose and supply protected power to the lower terminals.

Why is it that three inputs and three out are required for a single motor?

My question is why is there a bank of three and how should this correctly protect the pump motor correctly. Further, there is a tiny dial to the left of the unit that permits alteration on something. What is the dial for? Many thanks.

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Last edited by PJmax; 01-10-18 at 06:33 PM.
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  #2  
Old 01-10-18, 12:10 PM
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That is a 3 pole breaker. Used for 3 phase circuit. That is why there are extra terminals.

The dial is to adjust trip current (thermal side) of the breaker.

Thermal magnetic breakers are used where short circuit current has to be cut more quickly than regular breakers (thermal breakers).
I am not sure if pump motor falls under one of those cases. Magnetic side only activates with very high currently, which usually is a short circuit. Your breaker's magnetic tripping current is 170A according to the datasheet.
 
  #3  
Old 01-10-18, 12:23 PM
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Thank you for your comment. That explains some of my question. Does this mean that part of the unit is redundant as I have single phase only and or, do each of the sections do a separate job and therefore justify the connection between a lower terminal and an upper?
 
  #4  
Old 01-10-18, 02:19 PM
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Each of 3 poles will have their own trip mechanism. Using just part of the terminals is not a problem. All three will trip when one of pole trips.

therefore justify the connection between a lower terminal and an upper?
Is this wire on the same pole ?
Jumping between lower and upper terminal means the breaker is bypassed. If there are no extra wires, that wire is doing nothing.
 
  #5  
Old 01-10-18, 02:51 PM
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Thanks Lambition for the help. I've gone and had another look. The top left connection 1L1 has a negative supply in. Top centre is fed by a jump wire between lower left 2T1. This then becomes a positive supply feed at 3L2. Top right 5L3 is a positive supply in. Lower section is 2T1 that is a negative feeding top centre 3L2. Mid bottom is 4T2 and is a negative to the well pump. Lower right is 6T3 that is a live supply to the well pump. It does not seem correct that negative and positive should have been mixed here. Perhaps I wrong in my thinking but I feel is a bodge job. The wires to the pump then go via a pressure switch and capacitor. There are 3 wires that go to the pump and it seems no earth.
 
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  #6  
Old 01-10-18, 04:38 PM
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There are not negative or positive on AC system. You are confusing with neutral and line. Neutral (tied to ground at the panel) is not always needed and may not be present in your case. All the electronic device cares is voltage difference between 2 wires.
What voltage is your pump and which country are you located in?

If one of the pump wire is neutral it doesn't need to go through the breaker, but does not hurt to go through one either.
There is no reason to jump wire like that. Simply remove jumper wire and move wire on 4T2 to 2T1.
However, it will also work fine as is. It will just pass through one more breaker.
 
  #7  
Old 01-10-18, 06:08 PM
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hmmm. You are using a 3 phase thermal overload relay. When using with a single phase system (yours), you should run jumpers as shown. These contactors typically have phase out trip, and you need to "fool" it into thinking you have 3 active phases.
 
  #8  
Old 01-11-18, 01:39 AM
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Lambition. I was from the UK with the 220-240 volt system and negative, positive and earth on tree pin plugs and the positive always fused within a plug. I learned there that it was important to have the wires in the correct order with the live (positive) side fused. I now live in Portugal (GMT when posting) with 220-240 volts and the system permits appliance plugs to be inserted in two positions. There are no fuses to individual appliances and each property space (living room, bedroom, hall, garage) would ideally have an individual supply from the main fused circuit board. Each supply will legally permit eight power outlets. In Portugal a huge number of properties do not even have an earth attached to the electrical supply. Mine does not in practice. There is a green/yellow cable but it's attached to almost nothing. I suspect it was added to the system in about 1997 when a new water pump was installed but was not integrated into the finished wiring.

Often in Portugal, parts are used on a make do basis, hence the 3 phase circuit breaker. I installed a new pressure tank as the old was blown and rusted and was short cycling the pump for 3 seconds every 4 - 5 minutes due to underground leaks. They are yet to be repaired. Between the new pressure cylinder and correct setting on the pressure switch, the pump now operates for 40 seconds at a time. Better for the pump.

The job now is to improve the wiring side so that the pump is protected as much as possible. Part of my confusion is being in a country where I don't fully understand the electrics and having never had a well supply to contend with, plus, having a 3 phase circuit breaker for no good reason and wiring that makes little sense. Portugal is great but has some odd ways.
 
  #9  
Old 01-11-18, 01:55 AM
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Telecom guy. Thanks for the reply. All the wiring in the property ideally needs to be updated and drastically improved. I'm not entirely sure I understand what you mean. If the 3 pole circuit breaker is divided into 3 identical parts, does each pole do the same job or protect in different ways. Here's my ignorance showing.

My terminology will not be correct here but I ask myself if with the pump having a soft initial start wire and then a full working pressure wire, each of those pump wire parts needs separate protection whilst in operation. My knowledge on the pump workings is limited to what I've discovered on the web. I don't even know the make or model of the pump as it's 80 metres down a borehole. All I can determine is that it has 3 wires and somewhere, though not visible anywhere, a ground/earth wire as must be the case though VERY possibly not in use given the lack of earth/ground within the wiring system.
 
  #10  
Old 01-11-18, 04:24 AM
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If this breaker has phase out detecting circuit as telecom guy said, then you should leave the wiring as is.
Since the breaker is meant for a 3 phase motor, it is very possibility.

Changing how the breaker is wired will not protect the motor any safer.
 
  #11  
Old 01-11-18, 05:26 AM
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Note that your breaker has three modes of operation. The magnetic trip occurs at 170Amps, and is pretty quick responding. The second part is a thermal overload. This is adjustable from 9 to 14 A by the little wheel. The third function is phase out trip.
It is very common to jumper 3 phase protectors to accomodate single phase motors.
 
  #12  
Old 01-13-18, 12:45 AM
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Lambition and Telecom Guy. Excuse the delay in my reply. Been away from the PC for a couple of days. Thank you both for very full explanations that clarifies the workings of the switch the current wiring. I shall leave the connection ways as is and just move it all to a more appropriate place. Again, thank you so much for your time.
 
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