KILL SWITCH

[2windy]

What kind of switch can be used to short the wind genny out in stormy weather? I've have asked the question before on breakers and took everyones advice to stick with DC switches for DC current. I'm thinking this might be different beings I am bringing 3-phase AC in to my control box. Now comes the dumb question again, can I use a 3 pole 60 amp AC breaker as a short out switch? I really don't need the breaker, it just would be used as a on - off switch [it was free]

[DanB]

the breaker might work - though they trip to open circuit which isnt ideal.  A nice big DPST switch is ideal.  Old DPST (or a double pole double throw is OK) knife switches work great.   There are a lot of workable things, a breaker would not be my first choice.

[dinges]

Sir,

What are circuit-breakers designed for?

What are switches designed for?

Use them accordingly.

Peter.

[nanotech]

I would look around for an old industrial equipment power switch.  You know the kind that you can lock out with a padlock?  The big grey hand-throw type?  Those are heavy duty, high amperage items and some of the bigger ones will already be set up for 3 phase operation......

[jlt]

i built this switch from copper that i found in a army surplus store. it needs to be installed after the rectifiers

[cdog]

After the rectifiers??? I had a possibly false understanding it should be before the rectifiers?

  Cdog.

[commanda]

Before the rectifiers is correct. Obviously, you need at least a two pole switch for a three phase generator. Rectifiers do fail open-circuit, in which case your switch won't shut down the gennie.

Amanda

[Scotth]

I'm using marine battery switches for everything including the main disconnect.You can get them cheap on ebay or the local marine salvage yard if you are lucky enough to have one nearby, and most are rated from 250 up to 600 amps.Because they are for marine use they are very heavy duty with big copper or brass lugs and positive detents so the switch stays switched.Another plus is most of them keep all your cable ends behind the switch,out of harm's way.

[Ungrounded Lightning Rod]

Marine battery switches are great.  Maybe overkill, but that's OK.

Another possibility, if you're not located near boating outlets, is the cutout switch for an air-conditioner.  Looks like a circuit breaker with no amperage rating embedded in the handle, but it's just a heavy-duty two-pole switch - typically in a weatherproof box suitable for mounting next to the AC compressor outdooors - or at the base of the mill's tower.

By the way:  That AC versus DC business is because AC is easier to interrupt, since it stops by itself twice per cycle, breaking an arc (if it hasn't gotten TOO much vapor and smoke along the path to ease the restart on the next half-cycle).  A DC rated switch will normally handle AC loads (of equivalent amperage and voltage) just fine.

[cjdock]

I'm using a typical 2 pole 60amp main breaker from an old circuit breaker box as my kill switch. I took a piece of 6 gauge wire, maybe 3 inches long and tinned the ends. I stuck each end into the back of the breaker, where it normally clips into the circuit breaker box. I then ran 2 of the 3 wires from the genny into the front screws on the breaker, then the wire runs from those same screws to the bridge recitifiers. The genny brakes just fine using only two of the wires instead of all three. With the breaker in the "off" position, the genny is allowed to spin but when I flip the breaker on, it shorts the genny windings to stop it.

 The breaker fits nicely into a plastic single electrictly box which I screwed to a board.

[windstuffnow]

  I use a kill switch similar to yours but the switch arm is located on one of the ends and the three phase is run through each terminal.  When it needs to be shorted I throw the switch between all three terminals.  This way you only need one switch and there is no need for a run side and short side.

  I make them up on a nylon or plastic block with some 1/8" copper bar stock.  

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