electronic circuit help

[stilllogicz]

**broken link removed**

I have to take a test for a new position at my job and the guy who designed the test left me with a circuit he designed and told me if I could understand it I would be able to pass the test.

Basically, what happens when the S1 switch is pressed in relation to the circuit and what happens when the S2 switch is pressed?

Thanks big time for any help!

So far, if I'm correct, when I press S1 the power will flow to the K1 relay and through the normally open K1 circuits and close them, sending power to the light and turning it on.

Now, with the light on and pressing S2, I assume the the light will turn off, but how?

 

[stilllogicz]

Can anyone help me out here? I have to take the test tomorrow, please any clarification would be GREATLY appreciated!

 

[KeepItSimpleStupid]

Let me change your statement:

So far, if I'm correct, when I press S1 the power will flow to the K1 relay and through the normally open K1 circuits and close them, sending power to the light and turning it on.

When I press S1 the power will flow to the K1 relay which will close the K1 normally open contact and turn on the light. When I release S1, the K1 contact will stay closed. Furthermore, if power is lost K1 will drop out the K1 contact. On restoration of power, the light will be off.

Your turn for S2.

This is a variation of a circuit that could be found many times in a plant typically in simple motor control.

 

[stilllogicz]

That is exactly where I work, in a generator plant. Ok so upon release of S1, the K1 contacts will stay closed.

Now for S2, let's see...

Upon pressing S2, the power will flow to the K2 relay opening the normally closed K2 contact will which break the flow going into K1 in turn restoring the K1 contacts to their normally open position turning the light off?

Upon release of S2, the K2 relay will return to normally closed and the K1 relay contacts will stay normally open.

Btw, thanks for the reply KeepItSimpleStupid!

 

[KeepItSimpleStupid]

Yep. You were close and I hinted on the lack of power thing which made the rest make sense.

 

[stilllogicz]

Thanks! After I get this new job I will buy you the drink(s) of your choice!

So just to clarify, the K2 relay will return to closed after S2 is released?

 

[SABorn]

You are correct that by pushing switch 1 relay K1 will latch and 1 set of contacts in K1 will supply power to its own coil keeping K1 latched the second set of contacts in K1 will supply power to the light globe and the globe will light up.
Releasing the switch 1 the globe will stay lite as the relay K1 is latched

It should be noted that K1 is switching positive power to its self and the globe.

Pressing K2 will supply positive power to K2 coil and latch the relay as long as the switch is pressed, with K2 latched the Negative power to K1 coil is disconnected and hence K1 unlatches and the globe switches off.

I would also add the person who draw the circuit should learn how to draw a schematic correctly.
Secondly for a DC circuit he should included reverse diodes across the relay coils, although not needed for a simple globe but a good practice to adopt regardless of circuit application.

Good luck with your job interview.

Pete.

 

[KeepItSimpleStupid]

That's what I see.

 

[samina]

S1= push button swith, as long as u push it will remain close. So once u push it k1 will be energized and will close its contace, so the light will turn on .there is another contact of ki in parralel with s1 which will also be closed. So u no longer require to push the s1 to light on the bulb.
If you press s2 k2 will be energized its normally closed contact will be open and the supply will be disrupted.. So the light will be off

 

[SABorn]

That's what I see.

Yes i know but i was typing as you answered, and was a little slower than you so we ended up with cross posts, little point removing it once posted.

Pete.

 

[stilllogicz]

Thanks for the help guys + rep to all!

Yea the guy who gave me this diagram actually drew it up on paper, I drew it photoshop (although nowhere near as nice as he did on the paper =/)

 

[stilllogicz]

Just wanna update and let you guys know that I aced the test, 35 of 36 right!

 

[KeepItSimpleStupid]

Congratulations!

 

[SABorn]

The simple fact you bothered to ask and understand the circuit tells me you are willing to learn and move forward, so all the best for your future challenges and hope you enjoy the new position.

Out of curoisity what was the one you got wrong.

All the best

Pete.

 

[stilllogicz]

I have no clue, they didn't tell which one I got wrong, only that I got 35 correct.

 

[samina]

congratulation!!!!!!!