question on relay circuit......

[shaku]

Hi Shaku,
Now you are saying there is only two input and output lines look at #10 I already asked for it, give clear explanation ..
I think you in need of a black box which automatically detects the input and gives the output right??

Hi venkadeshm,
I am not sure why i did that way but after #10, you have re-draw diagram in #13 and then i have replied in #18 and asked you the same. I am not looking for black box as i have defined that need to detect ac or dc by using any method. I know it is not a regular thing but could be possible with electrical circuit.

At this point, my hope is some kind of relay circuit which can switch ac and dc.

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Hi kam,
This is small project as a curicullam part of semister. I did not get your post.
Thank you for the response.

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A good link for Solid State Relays (SSR) is found here. https://en.wikipedia.org/wiki/Solid-state_relay
It is only a couple of pages and worth a read. Especially the section on Advantages and Disadvantages.

Whether a SSR or a standard contact relay is used the solution is nearly the same. You need to sense the input voltage and depending on the voltage either drive the correct relay coil or pass current through the opto device in the SSR. There are many ways to sense the voltage such as ADC's, or window comparators.

If you use a ADC you will need some "smarts" after the ADC to decode its digital output
To reduce part count I would probably use a cheap ADC and a CPLD, window comparator is also a good solution

From the last post we now know there is a single input that can range from 20-40VDC to 100-280VAC. One last question: does the control circuit need to be power by this input or is there a another power supply for the control circuit?

I'm assuming the following:
1.) there are two wires coming in: Ground and [20-40VDC to 100-280VAC]
2.) there are three wires on the output: Ground, 20-40VDC, and 100-280VAC
3.) the input and output ground are common (i.e. connected together)
4.) there are no additional connections or power supplies

Are these assumptions correct?

Hi HMS1021,
To answer your question, the control(relay) circuit powered by this power only. I don't want to use other power source to power-up control circuit.

(1.) yes two wires Ground and ac(100-280vac) "or" dc(20-40vdc) ("input is always either ac or dc, never come at same time.).
(2.) yes output is three wires Ground, ac(100-280vac), dc(20-40vdc).
(3.) yes we can have common ground for input and ouput.
(4.) no additional connections.

All four points are only related to "control(relay) circuit". Not to entire project.
Thank you for your time.

 

[Venkadesh_M]

This circuit will actuate relay when given input AC and with proper device values...

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The capacitor blocks DC and the relay can only actuate at the tile of AC applied.. for simplicity you can use a SSR for lesser power consumption and proper isolation...

 

[shaku]

This circuit will actuate relay when given input AC and with proper device values...View attachment 93506

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The capacitor blocks DC and the relay can only actuate at the tile of AC applied.. for simplicity you can use a SSR for lesser power consumption and proper isolation...

Hi venkadeshm,
question on your circuit:-
How about DC? How can we get DC on output side? (If caacitor blocks everytime, how will DC reach to relay?).
thank you!!

 

[Venkadesh_M]

this circuit is just used to detect the AC / DC. anyway you will need another highvoltage cuttoff circuit.. you have to give the DC through Normally closed contacts of this relay so that If AC is not available The Dc will be available..

 

[shaku]

this circuit is just used to detect the AC / DC. anyway you will need another highvoltage cuttoff circuit.. you have to give the DC through Normally closed contacts of this relay so that If AC is not available The Dc will be available..

As per circuit diagram, DC will always block through capacitor, so how will DC reach to Normally closed contacts??

 

[Venkadesh_M]

Its just blocked on the relay coil You can take directly from lines to NC..

 

[shaku]

Hi venkadeshm,
Could you please explain me how four diodes going to work (functionality) in your circuit?
I have attached circuit and that can be operate either AC or DC source. (Not both same time.)


Is this attached circuit looks like a correct? ( I am not sure about DC path.)
Thank you,
sjs

 

[Venkadesh_M]

Operation: They are just bridge rectifier, If it was DC then it will be blocked by Capacitor, If it is AC the capacitor allows and rectified output will go for relay...........

About Your circuit: Both AC and Dc sources were parallel, and any one of the source will be there at a time and you have to take the line for transformer from the top of the resistor and your are correct you did some mistakes in the DC part...

 

[shaku]

Operation: They are just bridge rectifier, If it was DC then it will be blocked by Capacitor, If it is AC the capacitor allows and rectified output will go for relay...........

About Your circuit: Both AC and Dc sources were parallel, and any one of the source will be there at a time and you have to take the line for transformer from the top of the resistor and your are correct you did some mistakes in the DC part...

Can you correct DC side? or Any suggestion? (I know you have already given but could you do it by making "circuit diagram"?)

Thanks,
sjs

 

[shaku]

Any help with circuit connections?

 

[shaku]

Operation: They are just bridge rectifier, If it was DC then it will be blocked by Capacitor, If it is AC the capacitor allows and rectified output will go for relay...........

About Your circuit: Both AC and Dc sources were parallel, and any one of the source will be there at a time and you have to take the line for transformer from the top of the resistor and your are correct you did some mistakes in the DC part...

Can you help me with the circuit wiring connections?

 

[Venkadesh_M]

Ok. first the circuit I have given is just to detect AC/DC its just a parallel part after this tere will be two independent relays for AC and DC with their own high voltage cuttoff circuit..

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you have to study the working of high voltage cuttoff circuit i have given i(with op amp)..