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Clare Snyder Clare Snyder is offline
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Default How the heck does a typical home transfer switch work?

On Wed, 17 Jul 2019 21:43:12 -0000 (UTC), "Arlen G. Holder"
wrote:

How the heck does a typical home transfer switch work?
https://i.postimg.cc/c49KfVwY/transfer01.jpg


Don't know why I'm getting involved here - but what you have is
basically 2 SPDT contactors - on in each box, that switch the incoming
feed to the main panel between the line and the generator. There are
two becuase you need one for each side of the line - L1 and L2

Each contactor has 2 coils. When coil 1 is energized the contactor
goesd toi position 1 - when coil 2 is energized it switches to
position 2.

It is (likely) controlled by generator control box via the "plastic
relay" which when not energized powers the contactor to the "line"
position and when energized to the "generator" position.

It is EXTREMELY unlikey for both relays , both contactors, or both of
any of the fuses in the switch assemblies to have failked so I would
likely start at the genset, You COULD confirm the functionality of
both relays and check all the fuses first if you want, but I expect
that will be wasted effort.

What genset do you have? Generac by chance??? Very high faikure
rate. Start the generator and check voltage output. Likely ZERO -
which means it will never transfer. Genset may need to be "flashed" if
it has not been used for years. No guarantee it is salvageable but
worth a try. Something you should LIKELY get a generator tech to look
at.


See
https://www.electricgeneratorsdirect...t_man_2013.pdf

Also see
www.comdac.com/literature/generac/0d4001reva.pdf





Mine isn't working so I need to figure out how it works first.

o My mains is two hots plus a neutral (i.e., it's not 3 phase)
o There are two duplicate transfer boxes (presumably one per hot phase?)
o Each box has a beefy fist-sized double-ended solenoid
o Each box has what looks like a plastic relay
o And then each box has a fuse strip & a junction strip

That's pretty much it, where I'm not sure which "side" of the main circuit
breaker this two-box transfer switch is on yet.

Before I can troubleshoot, I need to know how it works.
https://i.postimg.cc/N0wQX4Jm/transfer02.jpg

1. The beefy double-ended solenoid is labeled:
"Generac transfer switch pn #71340, 250VAC/100A"
"This transfer switch is for use with control module ass'y
#75595 - #79844 - #83494"
https://i.postimg.cc/TYq0GY8x/transfer03.jpg

2. The plastic relay is labeled
o Deltrol controls, 166F DPDT, coil 12 VDC,
o 1/3 HP 13 AMP 120 VAC
o 1/2 HP 13 AMP 277 VAC
o 3/4 HP 3 AMP 600 VAC
o 10 AMP 28 VCD
o 8600, 20552-81, 9346
https://i.postimg.cc/s20K8nkZ/transfer04.jpg

3. The 4 fuses are each labeled either Buss BBS-4 or BBS-5.
https://i.postimg.cc/DwTNdMhv/transfer05.jpg

4. The junction strip is labeled
o Utility 1
o Utility 2
o Load 1
o Load 2
o blank
o 23
o 194
https://i.postimg.cc/tgDN6rqM/transfer06.jpg

What is the role of each of those 4 parts in this transfer switch?
https://i.postimg.cc/V6L4ZxZw/transfer07.jpg