Author Topic: Need a certain type of switch that may not even exist..  (Read 4295 times)

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Offline DylanMTopic starter

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Need a certain type of switch that may not even exist..
« on: August 24, 2012, 09:34:32 am »
Hi all,

I'm currently designing a power supply and have come across a tricky situation. I have 4 leads coming off a toroidal transformer that can be configured in parallel or series, to provide different combinations of voltage and current. This is great, however I would like to be able to switch between these modes without having to take the power supply apart and resolder things. So I designed a configuration to switch between parallel and series orientation, but for it to work properly I need a switch that can, on one setting, close two circuits leaving the other two open and vice versa. But the two circuits being switched on or off cannot make electrical contact (this would short out the transformer which is obviously a huge problem).

A quick diagram might make this easier to explain:


So my question is, does the kind of switch I'm looking for even exist? And if so, what is it called?

Thanks
 

Offline Balaur

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Re: Need a certain type of switch that may not even exist..
« Reply #1 on: August 24, 2012, 09:56:28 am »
Could I suggest you an alternative approach?

The attached drawing shows how you can integrate the diode bridge in your solution. You can choose between a series (double the voltage) or alternate phase (doubling the effective current) configuration. You only need a single switch.

A simpler approach of this is used in a lot of linear PSUs to select half or full voltage to minimize power dissipation.

Cheers,
Dan


 

Offline Rerouter

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Offline Jimmy

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Re: Need a certain type of switch that may not even exist..
« Reply #3 on: August 24, 2012, 10:24:26 am »
Google Roatry changover switch one way on on off fff    middle off off off off  other way off off on on then you mechanicaly can't short it out
 

Offline DylanMTopic starter

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Re: Need a certain type of switch that may not even exist..
« Reply #4 on: August 24, 2012, 10:32:10 am »
Could I suggest you an alternative approach?

The attached drawing shows how you can integrate the diode bridge in your solution. You can choose between a series (double the voltage) or alternate phase (doubling the effective current) configuration. You only need a single switch.

A simpler approach of this is used in a lot of linear PSUs to select half or full voltage to minimize power dissipation.

Cheers,
Dan

Looks good, I might use that. Although I'm a little confused as to how it works though.. Are the two connections in the center of the secondary of the transformer joined, and which orientation of the switch would be parallel and which would be series?

here is the expensive approach http://au.element14.com/moeller/diler-22-230v50hz-240v60hz/mini-relay-2n0-2nc/dp/1109994

and here is the cheap approach http://au.element14.com/multicomp/1m43t1b5m1qe/switch-solder-tag-4pdt-on-off-on/dp/155019401

So what I was looking for does exist.. Thanks for the response but after seeing Balaur's solution I may only need a standard switch now.


Google Roatry changover switch one way on on off fff    middle off off off off  other way off off on on then you mechanicaly can't short it out

Again, thanks. But it may no longer be needed, I'll look into it if the circuit in Balaur's post doesn't work for me.
 

Offline Jimmy

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Re: Need a certain type of switch that may not even exist..
« Reply #5 on: August 24, 2012, 10:53:27 am »
Np   you didn't specify it was a dc power supply  ;)
 

Offline DylanMTopic starter

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Re: Need a certain type of switch that may not even exist..
« Reply #6 on: August 24, 2012, 11:17:27 am »
Np   you didn't specify it was a dc power supply  ;)

Haha sorry, I thought it would just be assumed :P
 

Offline DylanMTopic starter

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Re: Need a certain type of switch that may not even exist..
« Reply #7 on: August 24, 2012, 11:17:46 am »
Np   you didn't specify it was a dc power supply  ;)

Haha sorry, I thought it would just be assumed :P
 

Offline Rufus

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Re: Need a certain type of switch that may not even exist..
« Reply #8 on: August 24, 2012, 12:49:44 pm »
I have 4 leads coming off a toroidal transformer that can be configured in parallel or series, to provide different combinations of voltage and current.

As I understand the problem you need the most common type of switch.
 

Offline G7PSK

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Re: Need a certain type of switch that may not even exist..
« Reply #9 on: August 24, 2012, 03:27:09 pm »
4 pole 2 way switch is what you need.
 


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