Alternating polarity via CAP's

[wombweller]

Hi All

I would like to ask for advice on an alternating polarity circuit I have in mind.Please see the schematic I've attached of the proposed circuits.

The idea is to drive x2 500ohm bell coil's wired in series that requires and alternating pulse to run.As you maybe aware these old bell coils have a seesaw paddle on top that flips on each alternating pulse.Coil represented by LED's in the schematic.

The trigger represented by the switch will be pushed manually thus triggering the polarity change and flipping the seesaw paddle.

I'm not sure that my attempts are the best but would like to hear from those who can suggest a better method via other electronic components

Regards Mark

View attachment 61380.

 

[wombweller]

Hi

Here is another schematic but slightly differant...is this better than the last one?

View attachment 61381

 

[wombweller]

What if any are the benefits of the second CAP in the last schematic? The circuit needs to be as simple as possible.

 

[Reloadron]

I have no clue where you are going with this. Attached is a drawing of the early style bell I believe you are referring to. If you look at the pole of the electromagnet labeled S you can see how when power is applied the contacts make and break over and over again. It is basically an electro mechanical vibrator action. The switching is automatic.

What exactly are you trying to do?

If you just want to drive a pair of series coils, reversing polarity at some rate, consider using an H bridge circuit.

Ron

 

[wombweller]

I have no clue where you are going with this. Attached is a drawing of the early style bell I believe you are referring to. If you look at the pole of the electromagnet labeled S you can see how when power is applied the contacts make and break over and over again. It is basically an electro mechanical vibrator action. The switching is automatic.

What exactly are you trying to do?

If you just want to drive a pair of series coils, reversing polarity at some rate, consider using an H bridge circuit.

Ron

Hi Ron
The info I'm looking for is advice on a circuit that will give me an alternating pulse able to drive the electromagnets on the old bell.In my first schematic I used only one cap but if you see the second schematic it uses two,there may be better ways than I've shown and that's what I looking for. I will look at H bridge circuits.

The switching device for the magnets will be a 1 sec beat pendulum, when the pendulum moves far right and left the switch is made thus activating the electromagnets the electromagnets drive other components but for the moment I'm only looking at the suggested alternating polarity circuit.

 

[Reloadron]

The old bells do it automatically if you look closely at the drawing. Now if you want to do this manually it can be done easily using a simple DPDT switch and a cap upstream (power supply side of switch) with your coils downstream. Later this evening (at work now) I can give you a drawing that will do that. Electronically using an H bridge and manually using a switch. I forgot to mention a simple DPDT switch in my first post.

Ron

 

[Reloadron]

Attached shows how I would switch polarity with a cap in the circuit as I mentioned. This is just a rough idea.

Ron

 

[wombweller]

Attached shows how I would switch polarity with a cap in the circuit as I mentioned. This is just a rough idea.

Ron

Hi Ron

Thanks for that!! I have used this method many times mainly because it's a sound method but I did want to look at alternatives and some suggested the CAP's

Cheers