Shunt Trip

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john37

Senior Member
I'm trying to connect a emergency pushbutton to disconnect 3 1P20A breakers in a 208/120V, 3 ph panel and also with the same pushbutton disconnect a 480V, 3 ph X-ray power generator. Does this diagram look right or am I totally off base? Thanks.
 

ohmhead

Senior Member
Location
ORLANDO FLA
I'm trying to connect a emergency pushbutton to disconnect 3 1P20A breakers in a 208/120V, 3 ph panel and also with the same pushbutton disconnect a 480V, 3 ph X-ray power generator. Does this diagram look right or am I totally off base? Thanks.

Well its ok if thats what you want looks ok .

I would show the neutral connection to each breaker more so and the hot connection to the contacts on one side but its clear what you are showing looks fine to me .

Question why the seperate control relay for the 480 volts breaker why not use one of the spare contacts ?
 
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I'm trying to connect a emergency pushbutton to disconnect 3 1P20A breakers in a 208/120V, 3 ph panel and also with the same pushbutton disconnect a 480V, 3 ph X-ray power generator. Does this diagram look right or am I totally off base? Thanks.
I dont understand the other relay contactor when you have spares :-?
 

benaround

Senior Member
Location
Arizona
John,

I don't see any circuit to the ST breaker, usually it is 120vac the same as your EMO. Also,

the drawing shows the EMO open and the (3) 120v circuits open, I don't think that is what

you intended to show.
 
How's this one? Do you think it is clarifies it better? Thanks.

  1. Incomplete circuits.
  2. Does not understand what the various 'cannon sensor', 'cannon server' etc. are If they are interrupting the circuit, the shunt trip would not work.
  3. The internal shunt trip unit contact should be shown adjacent to the shunt trip coil.
  4. Bad graphical representation, does not agree with the convention of power on the left and grounded wire on the right. Elements that change the logic state of the circuits are starting adjacent to the power and the last element is the activated element, coil, etc. (Or top and bottom if you use IEC.)
  5. All your eggs in one basket; if you loose the single 120V circuit, none of the shunt trips would work.
  6. To secure power loss trip, the interposing relay should be used in the energized state and all contacts and the single manual actuator should use NC contacts.
 

Besoeker

Senior Member
Location
UK
I'm trying to connect a emergency pushbutton to disconnect 3 1P20A breakers in a 208/120V, 3 ph panel and also with the same pushbutton disconnect a 480V, 3 ph X-ray power generator. Does this diagram look right or am I totally off base? Thanks.
No retaining contacts.
Take your finger off the button and everything drops out.
Is that what you intended?
 

benaround

Senior Member
Location
Arizona
How's this one? Do you think it is clarifies it better? Thanks.
No. It does not show how anything works. A person with no clue needs to be able to see

exactly how the circuit is to be wired.

1. The drawing shows a 100a 3ph circuit going thru a contact of a relay ???

John, you have to show the 120vac control circuit going thru an open contact and

then to the coil of the shunt trip and the neutral going to the other side of the coil.

2. You should show the neutral going to the sensors also.

3. You need to give some thought to the EMO, if the EMO is n.o. then the contacts for

the sensors need to be n.c. and the ST n.o.

Give it another shot, I'll check back tomorrow.
 

john37

Senior Member
Frank...Thank you for your comments. I gave it another shot. Please see attached diagram. Anyone please comment as well.
Excuse my ignorance on this matter. I'm really trying to understand the proper way to do it.
 

hillbilly1

Senior Member
Location
Atlanta,Ga
Occupation
Field coordinator/ technical support
Frank...Thank you for your comments. I gave it another shot. Please see attached diagram. Anyone please comment as well.
Excuse my ignorance on this matter. I'm really trying to understand the proper way to do it.
The shunt trip breakers are not internally powered, so your diagram will not work, I would get rid of all of the contacts, use the power for the E-Stop to power all shunts. If this circuit loses power, the shunts would not work anyway even if they were run through individual contacts and individual circuits. Use the KISS philosophy, (Keep It Simple Stupid!) I would use a maintained position E-Stop so that it would have to be reset before the breakers could be reset.:smile:
 
Ok....Tried it again. Taking Hillbilly's comments into consideration (if I understood it correctly) I revised the diagram. Would this work now? Thanks.
From the control standpoint it retains the inherent problem with shunt trips. It operates in a passive failure mode. Until you attempt to operate it you won't know if it is 'healthy' and that it will operate.
Potential remedy steps:
  1. UPS supply, monitored.
  2. Individual supply for each circuits, monitored.
  3. Low voltage, high resistance circuit monitoring for each individal shunt trip circuit for open circuit. (GE Genius I/O)
 

hillbilly1

Senior Member
Location
Atlanta,Ga
Occupation
Field coordinator/ technical support
From the control standpoint it retains the inherent problem with shunt trips. It operates in a passive failure mode. Until you attempt to operate it you won't know if it is 'healthy' and that it will operate.
Potential remedy steps:
  1. UPS supply, monitored.
  2. Individual supply for each circuits, monitored.
  3. Low voltage, high resistance circuit monitoring for each individal shunt trip circuit for open circuit. (GE Genius I/O)
Most shunt trips are not monitored, though the above suggestions can be used, most are powered from the same feed that the shunt breaker disconnects, since one pushbutton is being used, if the power supply to it fails, all shunt trips will fail because the relay will not be energized. Three contact blocks on the pushbutton could be used to eliminate that problem, that, with each shunt trip breaker receiving it's control power from it's own source would be the easiest way to guarantee activation, if the source is already off, the breaker would not be supplying the load anyway.
 

hillbilly1

Senior Member
Location
Atlanta,Ga
Occupation
Field coordinator/ technical support
If you want to monitor the control circuit power, install a lighted pushbutton or a seperate Led pilot light, light on, circuit power available. Cheap, reliable, and simple.
 
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