On Dec 17, 1:50*pm, nesesu wrote:
On Dec 17, 10:59*am, klem kedidelhopper
wrote:





Our area suffers from frequent blackouts, and many people including
myself use generators, (manually) during these periods. It would be
really helpful to know when the utility side of the circuit is once
again live so that I can put the generator away. Basically I need to
monitor the entrance cable side ahead of the main.
I thought about the simplest way which would be to wire a small NE2
neon lamp across the 240, ahead of the main, (with the appropriate
series resistor of course). The lamp would be lit all the time there
is utility supplied power and off during a blackout. The plan is to
not have to uselessly be running my generator after power unbeknown to
me is restored. The down side of this if it is really any concern
would be that this lamp, small as it as well as its associated wiring
would be would not be protected by a breaker.
The lamp is of course the simplest way, but I was wondering if there
is some sort of inductive circuit someone may know of that that would
not require that current be flowing through a conductor, basically a
circuit *that would indicate the presence of voltage.
For instance I carry a *little "pen" shaped device *in my tool box. I
press and hold an on button and the unit chirps when brought near a
hot AC circuit. It's a great time saver when trouble shooting a job,
but can something like this be implemented as a full time monitor
circuit? It could be powered off small rechargeable batteries and
always indicate the state of the entrance cable. Thanks, Lenny

Lenny, try taking a plain NE-2 with no resistor and connecting about a
foot of insulated #22 solid insulated wire to one lead and wrapping
that around a piece of insulated wire the same size as your service
entrance wire and connecting the other lamp lead to neutral. Energise
the heavy wire with 120V and see if the NE-2 glows just from the
capacitance of the large wire to small wire. That is about as simple
as it gets and is adequately insulated from the service cable to not
need any current protection.

Neil S.- Hide quoted text -

- Show quoted text -

Fantastic idea!!!