If you have a room light on, and you turn it’s switch to on, isn’t it still on and there was no change?

Using two relays for a quick example, say this is the initial state

A Set
B Reset

You toggle B and press the button. A gets set; B gets set. The result is

A Set
B Set

A doesn’t change and the result is what you want

Yea got it!
So each relay draws 200mA so i need to select a momentary toggle/pushbutton which is rated for atleast 2A. Considering the fact that applying pulse again to the Relay coil won't cause any damage!

 

OK, here's a new drawing. Having looked at it this way I see that there's a potential to have six NEON bulbs in series ON. In that case, 400 ÷ 6 = 66.6 volts dropped with each one. Potentially all six bulbs on at the same time, 66 volts might not be enough to light them. But if all but one relay is open (off - or RESET) then the full 400 V will want to pass through the single NEON bulb. Meaning you're going to have serious issues with resistors. Off hand I just don't know how that's going to work out. Perhaps each NEON needs to be calculated for a worst case scenario where only one NEON is lit at 400V. I don't know if that exceeds the rating of a typical NEON bulb or if resisting enough current will become an issue. But here's the drawing WITH NEON's in circuit. Relays A & B are "SET" and the rest are "RESET". Pushing the single momentary PB will set all relays to that configuration.

 

OK, here's a new drawing. Having looked at it this way I see that there's a potential to have six NEON bulbs in series ON. In that case, 400 ÷ 6 = 66.6 volts dropped with each one. Potentially all six bulbs on at the same time, 66 volts might not be enough to light them. But if all but one relay is open (off - or RESET) then the full 400 V will want to pass through the single NEON bulb. Meaning you're going to have serious issues with resistors. Off hand I just don't know how that's going to work out. Perhaps each NEON needs to be calculated for a worst case scenario where only one NEON is lit at 400V. I don't know if that exceeds the rating of a typical NEON bulb or if resisting enough current will become an issue. But here's the drawing WITH NEON's in circuit. Relays A & B are "SET" and the rest are "RESET". Pushing the single momentary PB will set all relays to that configuration.
View attachment 227966

If you do that, I recommend placing a diode around each relay coil or your going to run into back EMF issues.

 

Edited post #75

In the TS's drawing there are six relays, each drawing 40mA. [edit] 200mA [end edit] each. Six relays set at the same time would draw 240mA. [edit] 1.2A. [end edit] A single PB should be able to handle that current.

 

Yea got it!
So each relay draws 200mA so i need to select a momentary toggle/pushbutton which is rated for atleast 2A. Considering the fact that applying pulse again to the Relay coil won't cause any damage!

Nope. Pulsing a coil twice won’t damage it.

 

If you do that, I recommend placing a diode around each coil or your going to run into back EMF issues.

Good point. However, I don't think the toggles will have any issues dealing with the BEMF. Especially if the switches are set then the PB is pressed. Perhaps the Momentary PB might though. Perhaps a snubber circuit on that to handle the BEMF.

 

OK, here's a new drawing. Having looked at it this way I see that there's a potential to have six NEON bulbs in series ON. In that case, 400 ÷ 6 = 66.6 volts dropped with each one. Potentially all six bulbs on at the same time, 66 volts might not be enough to light them. But if all but one relay is open (off - or RESET) then the full 400 V will want to pass through the single NEON bulb. Meaning you're going to have serious issues with resistors. Off hand I just don't know how that's going to work out. Perhaps each NEON needs to be calculated for a worst case scenario where only one NEON is lit at 400V. I don't know if that exceeds the rating of a typical NEON bulb or if resisting enough current will become an issue. But here's the drawing WITH NEON's in circuit. Relays A & B are "SET" and the rest are "RESET". Pushing the single momentary PB will set all relays to that configuration.
View attachment 227966

Yea need to consider many things if i want to go with neon indicator but i will give it a thought. I think the easy way as u guys suggested would be to use a normal SPDT switch to Set/Reset and only one common momentary switch to give pulse to activate the coil.

 

Good point. However, I don't think the toggles will have any issues dealing with the BEMF. Especially if the switches are set then the PB is pressed. Perhaps the Momentary PB might though. Perhaps a snubber circuit on that to handle the BEMF.

If bad enough, the back EMF can cause false triggering of other relays. its better to just add them.

 

Not to argue the point, but I believe with the toggles set in their needed positions, the push of the push button will direct the relays to act accordingly. Even if there's a BEMF, the toggles will direct the coils to latch. Am I wrong? I'm open to listening to differing points of view. The only affect the BEMF might have is on the contacts of the PB.

 

On the subject of BEMF - perhaps the coils (chokes) should have snubbers as well. That'll protect the relay contacts from BEMF. And the NEON's and resistors in parallel to the coils - that's going to change how the circuit works as well.

 

Yea need to consider many things if i want to go with neon indicator but i will give it a thought. I think the easy way as u guys suggested would be to use a normal SPDT switch to Set/Reset and only one common momentary switch to give pulse to activate the coil.

If i do this way, do i need to consider placing a diode across the coil?
I believe i won't be needing any since i am not doing live switching.
Please advice me on this

 

Not to argue the point, but I believe with the toggles set in their needed positions, the push of the push button will direct the relays to act accordingly. Even if there's a BEMF, the toggles will direct the coils to latch. Am I wrong? I'm open to listening to differing points of view. The only affect the BEMF might have is on the contacts of the PB.

EMF doesn't need wires to affect nearby components.

 

Manjesh Gowda are you trying to make a tunable inverter?

 

Not to argue the point, but I believe with the toggles set in their needed positions, the push of the push button will direct the relays to act accordingly. Even if there's a BEMF, the toggles will direct the coils to latch. Am I wrong? I'm open to listening to differing points of view. The only affect the BEMF might have is on the contacts of the PB.

That’s right... The toggles change position while no power is applied. The coils aren’t energized and there is no stored energy to dissipate.

BUT, when the pushbutton is released, the stored energy of 10 (or whatever) coils will result in BEMF. Could that weld a toggle contact?

The pushbutton is definitely at risk. At least one (properly sized) diode is recommended.

 

Did anyone suggest just using a set-reset FF circuit to mirror the power relay and light an indicator to indicate the relay's state?

 

Manjesh Gowda are you trying to make a tunable inverter?

Yes i am making a tunable network for the Resonant converter!

 

Did anyone suggest just using a set-reset FF circuit to mirror the power relay and light an indicator to indicate the relay's state?

Yes

 

If i do this way, do i need to consider placing a diode across the coil?
I believe i won't be needing any since i am not doing live switching.
Please advice me on this

Yes. Across each relay coil. It doesn't matter if the load is energized or not.
But another thing to consider is the possible affect on nearby components.
Its better just to add them and eliminate possible emf affects.

 

Did anyone suggest just using a set-reset FF circuit to mirror the power relay and light an indicator to indicate the relay's state?

Yes, I believe someone mentioned 4013 DD FF's.

 

Yes, I believe someone mentioned 4013 DD FF's.

Post #72