Can anyone tell me What is lOck out Relay with
associated circuit diagram ?
Advanced thanks
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Can anyone tell me What is lOck out Relay with
associated circuit diagram ?
Advanced thanks
Locked out relays are electromagnetic switch with normally open and normally closed contacts. Their functions according to how they are connected in the circuit.
typically they will be triggered when a safety switch opens such as low pressure or high pressure condition. The system will be off until the power is reset
Quote:
Originally Posted by Shibhrac
First some statements:Quote:
Originally Posted by Abby Normal
1. The lockout relay has a high impedance coil.
2. Electricity will always go the easiest through a circuit (to ground).
How it works:
under normal operation the current going through the lockout relay coil will not be enough to energize the coil.
ones one of the safeties trips, the easiest current path will be through the lockout relay coil and compressor contactor (CC). ones the lockout relay is energized is will open the NC switch on it, and prevent compressor from starting. even when the safety returns to NC position. in order to reset the lockout relay power must be broken to the lockout rely coil.
[IMG]file:///tmp/moz-screenshot.jpg[/IMG]
[quote=myrsve;161817]First some statements:
1. The lockout relay has a high impedance coil.
2. Electricity will always go the easiest through a circuit (to ground).
How it works:
under normal operation the current going through the lockout relay coil will not be enough to energize the coil.
ones one of the safeties trips, the easiest current path will be through the lockout relay coil and compressor contactor (CC). ones the lockout relay is energized is will open the NC switch on it, and prevent compressor from starting. even when the safety returns to NC position. in order to reset the lockout relay power must be broken to the lockout rely coil.
Attachment 3088
Here is basic diagram with memory relay which I just draw (function as High Pressure trip memory and alarm).
http://farm4.static.flickr.com/3517/...e038ef_o_d.png
Hmmm... that doesn't look quite right. I think the HP pressurestat is hooked up wrong. It should tie in on the other side of the 1K3 contacts, so that it can energize the relay.Quote:
Originally Posted by nike123
corrected some mistakes you madeQuote:
Originally Posted by nike123
Attachment 3089
Sorry but that is also wrong. It should be as Gary said.Quote:
Originally Posted by myrsve
And it was at first, when I draw it, but I made some rearrangement for better look and made mistake with that connection.:confused:
http://www.refrigeration-engineer.co...pictureid=1213
Now to explain this diagram. Above is display of de-energized contacts of memory relay as it appears in electrical diagrams by EN standard
- Normal state
When there is no error, compressor contactor is energized/de-energized by thermostat 1B1 thru 21-22 NC contacts of 1K3 memory relay. Memory relay is de-energized since HP pressure contact is NO type and open when pressure is below set value (close on rise). Also, memory relay 13-14 NO contact is open and circuit cannot be closed thru it. Signal lamp is de energized because of NO contact 33-34 of memory relay.
http://www.refrigeration-engineer.co...pictureid=1217- HP error present
HP pressurestat NO contact is closed and memory relay is energized. Contacts of relay switch position, and NC contact 21-22 became open and cut off supply to contactor. NO contact 13-14 is now closed and memory relay is also energized thru that contact. NO contact 33-34 closes and alarm lamp is energized.
http://www.refrigeration-engineer.co...pictureid=1222- HP error is not present, memory effect
HP pressure error stops and pressurestat NO contact is open, but memory relay is energized thru its own NO contact 13-14 (now closed) and closed push button NC contact, and everything else remains same as if the high pressure error is still present.
http://www.refrigeration-engineer.co...pictureid=1221- Trying to reset with high pressure error still present
Pressurestat NO contact is closed and memory relay is still energized. Push button is pressed (NC contact opens) and circuit is interrupted between live and 13 connection, but connection 14 is energized thru now closed NO contact of HP pressurestat. Nothing changes and reset could not be done when high pressure is still present.
http://www.refrigeration-engineer.co...pictureid=1223- Reset when there is no high pressure error
HP pressurestat NO contact is open, and by briefly opening NC contact at reset button, memory relay is de-energized.
Before switchover:
http://www.refrigeration-engineer.co...pictureid=1218
After:
http://www.refrigeration-engineer.co...pictureid=1219
Its contacts switch position and NO contact 13-14 is now open. When push button is depressed, memory relay is not energized because open NO contact 13-14 and HP pressurestat NO contact are now open contacts. NO contact 33-34 is also open and alarm lamp is de-energized. NC contact 21-22 is now closed and contactor could be energized/de-energized thru termostat contacts.
Guys, correct me if I draw something wrong, i will fix it!
Yep, you are right! I made correction.Quote:
Originally Posted by Gary
okay I see you point. but my drawing is not wrong. it will still work the only difference it the light will go off when there is a trip.Quote:
Originally Posted by nike123
my only concern is that in your drawing, if there is a wire break between the HP switch and connection point. the unit will not trip on Highhead.
Ok, but then Reset push button should be renamed as Start push button and signal lamp function is then to signal corect operation not alarm condition.Quote:
Originally Posted by myrsve
http://www.refrigeration-engineer.co...pictureid=1224
Also, in your first drawing, there is no thermostat.
Correct me if I am wrong, but if you place thermostat anywhere, that circuit will reset itself whenever termostat is not calling, if placed out of relay loop, and it will activate lock out if placed inside relay loop.
Function of lock-out relay (in our examples) is to forbid function of compresor until power is interupted or error is no more present but manually reset must be done.
In your example, if we introduce thermostat, that is not the case:
http://i37.tinypic.com/2utgrd5.jpg
First: there is a thermostat. Y1 is a stander marking for 1. stage cooling on thermostats. at least here in the US, in the relation to air conditioning.Quote:
Originally Posted by nike123
second: yes it is true that if the thermostat cycles of it will reset the lockout relay. that means that the thermostat needs to meet setpoint to cycle of or some one will need to manually cycle the thermostat.
third: in your circuit if there is a power interruption between L and N. Your system will reset on it own.
PS: nice drawings. I miss the IEC drawings, don't see them over here. except on PETRA units.
Four: the person asked for a lockout relay. I drew what came to mind. Checkout icm controls if you have time
Attachment 3090
here is a update. hope fully everybody understands this one.
PS: How do I edit my post. so i don't have to repost for every little thing.
At the bottom of each of your post should be EDIT button.Quote:
Originally Posted by myrsve
Me too. Sorry if you see this as competition. It was not that!Quote:
Originally Posted by myrsve
It is only different approach! And it is good thing because interested could learn about pro and contra of each approach.
What is Icm controls? Company you work for?
It was fun ville it lasted. it is a good thing to see problems from different perspectives.Quote:
Originally Posted by nike123
ICM controls is a controls products company. i don't have the minimum post count to link the web address.
icmcontrols . com