A/B Power switch

[veggie]

Can anyone recommend an A/B switch like the one illustrated in this sketch.
Having trouble finding one.

Basically, I want to provide 120vac power to the loads from two different sources.

Thanks,
veggie

[mobile_bob]

look on ebay for a "reversing contactor"
the are electrically and mechanically interlocked so only on side can be on at once.

they come in all sizes and prices

bob g

[mobile_bob]

i dunno, they make some small ones, and sometimes you can get them quite reasonably
look for 3phase though, as single phase reversing contactors are relatively rare surplus.

or you can use a dpdt relay but there is no interlock, which may or may not be an issue for you?

bob g

[veggie]

Turns out the boat guys use them.
Have a look at this....

(bit pricey @ $140)

*******SPECS******

Blue Sea 8366 AC Rotary Switch Panel 30 Ampere 3
Positions + OFF, 2 Pole

Poles: 2
Voltage: 120v
Amperage: 30
Positions: 3 + OFF

    * Switches 3 - 120 Volt AC sources
    * Includes 9011 heavy duty industrial rated switch
    * Two-part polyurethane slate gray finish
    * Heavy 1/8" aluminum 5052 alloy
    * Red reverse polarity LED indicators
    * Green power available LED indicators
    * Switches AC sources
    * Compact solution when circuit protection is provided elsewhere
    * Allows connecting one of two or three different AC sources to one circuit
    * Includes heavy duty industrial-rated switch
    * Red reverse polarity LED indicators
    * Green power-available LED indicators

veggie

[Lloyd]

Boat guys do use em all the time, but this is a new market for the blue seas guys. Old guy use Multi deck switches(Krausse Naimer) they are a beautiful thing, you can order them up in almost any config...make before you break, or the reverse? No of poles, and throws will boggle the mind.

Lloyd

[mobile_bob]

to give you an idea of what is available in the way of reversing contactors

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=250573640705&ssPageName=STRK:MEWNX:IT

this one is a three phase, so it has extra sets of contacts for repair parts later down the road if used as a single phase unit
it has a 48volt coil which is what i need, it is new unused and comes with those wire jumpers which will be removed or repositioned
depending on end use

they are break before make, which is probably what most folks want so as not to close in on the grid or inverter close on genset, etc.
they are mechanically interlocked meaning that you can have A or B but cannot have both, under any circumstances
they are electrically interlocked, as a second control handle or lockout.

nice compact package and reasonably priced in my opinion
it allows remote switching with something as small as a twisted pair and a toggle switch, or a relay controlled by a microcontroller system
or whatever.

these puppies come in all sizes from small that are relatively inexpensive, up to huge, which cost huge dollars even used or surplus

bob g

[Lloyd]

(Professor) Bob,

Those are nice looking switches.
edit to add... in single phase you could switch 3..triple pole.

Here is a link to some info on the deck switches http://pdf.directindustry.com/pdf/kraus-naimer/catalog-100-c-ca-cad-cl-l-switches-10a-2400a/4870-81033-_4.html

Lloyd

[highwater]

Hi veggie

I realize your probably looking for something commercial OTS for the long term, but if you need to get by for a period of time, you could use/modify a 2 pole knife switch type manual disconnect.

Randall

[Chris]

If you don't need to switch the neutrals, just use a common 3w household switch 120 volts. The type used to switch on, say a light, from two dirrent switches. Connect the neutrals together and wire up the hots to the switch. 15 and 20 amps common. Higher amps? I think you can also find similar switches in 240 volts where you could switch the neutrals. Also try places like Westmarine or auto supply stores "NAPA" I have found double poles switches at those types of places usually under $10.00. There is also a link on  www.utterpower.com/transfer_switch.htm  showing how to use common breakers to make a transfere swith with an interlock. (Sorry the hyper link did not copy).

Good luck,

Chris

[veggie]

Thanks for the link Chris.
Looks like an interesting solution.
And it's inexpensive 

veggie