On Sat, 27 Feb 2010 22:30:00 -0500, "Jon"
wrote:

I. GENERATOR TRANSFER CIRCUIT

The service wire is 000. I'm not even going to attempt a contactor for
that. I'd have to wire it hot and there's too much risk.

No, you get an electrican who can interrupt the power to do the
connection(s).

All I'm going to
do is make a fail-safe circuit to protect the generator when the power goes
back on.

Neat trick, but that's no the issue. You need to prevent backfeeding
the power system even when the power is OFF.

It's only a 10kw generator so I'm using 120vac coil contactor with
contacts rated for 90amps. I'm going to use the spare wire from the house
to the barn to signal when the grid goes back on. That will open the
circuit and shut down the generator.

This absolutely, positively won't work the way you think it will. It
also will violate both safety and probably legal rules.


view in courier

service

120vac 120vac signal
o o o
| | |
o o------------*
\ main \ |
o o |
| | |
| house | |
| | |
| | |
| barn | (COIL)
--- --- | generator ignition
-/- N.C. -/- N.C.. | o
| | | |
o generator o | ---
--- --- N.O.
- |
gnd |
---
-
chassis

II. ALARM CLOCK.

I'm trying to wire a 120vac 150 mA fire alarm horn into the alarm of a
digital clock. I already did one with a fire bell. This clock is
different. It's a radio alarm clock, and the beeper alarm goes through the
speaker. I can't seem to get enough juice out of the speaker into the
transistor base for collecter-emitter flow to activate the 6vdc coil of my
relay with 6amp contacts. I'm using 10vdc from a circuit in the clock to
power the relay coil.

10vdc
o
|
*--------*
| |
R1=1k R2=1k
| |
| |
| |
\ |
T |-------*-----o red 120vac o
/ | |
| speaker 1.5vdc ---
| | --- N.O.
(coil) o black |
| buzzer
| |
--- ---
- -
clock common
gnd

I'm just a heavy sleeper and want something a little more lowder to wake me
up.