I don't claim to have really followed it, but do know that the contacts on
my TS relay fused closed. Unless your device accomodates that (on the line
contacts) safely, it is no good.

"Ignoramus25850" wrote in message
...
I have been playing with using relays of various kinds, as well as
contactors. I already built 2 phase converters, and a remote switch,
for instance. I have a few 90A and 75A contactors and solid state
relays and mag starter buttons and whatnot.

Here's what I have been thinking about. I have a 7 kW Onan DJE
generator that I have for emergencies. I want it to power my entire
house in emergencies (I know that I cannot run AC and some other
devices while under generator power).

It is expensive and painful to install a transfer switch. I want to
make something easier and cheaper to power the house in case of
emergencies, while at the same time preventing backfeeding.

I can, instead of a transfer switch, build a system that includes a
contactor, a mag starter, and a relay that only closes the main
generator contactor when the main circuit breaker is in the OFF
position.

It would work something like this. There will be a mechanical device
and a switch such that the switch could be closed only when the main
breaker is off. When the main breaker is on, the switch could not be
closed.

Where I live the utilities require physcial and electrical interlocks.
Most residential panels do not lend themselves to a physcial interlock.
Square D is the only one that I know of that has a physical interlock
between the main and another breaker.
Then comes to the issue of the equipment being service rated. Then comes UL
listings.
A contactor/motor starter off the shelf I do not believe is service rated.


There will be a DC circuit, powered by a 9V battery, that would be a
signal input to a solid state crydom relay. The power contacts of the
relay would be in series with the power from generator. When the relay
is closed (only when the mains breaker is open), and a START button is
pressed on the start/stop switch (like ones used for mag starters),
the main contactor would close. The STOP button interrupts input to
the contactor, causing it to open. Turning the little switch near the
main breaker off would also interrupt the circuit, opening the
contactor.

This seems to be a very fool proof system. I can build it in 30
minutes, except that I would need more time to fabricate a mechanical
switch opener/closer.

I would like to ask that those who can visualize what I am describing,
to comment on this plan. Thanks

i

Check with your local authorities and utility before embarking on the
project.
If you can build this in 30 minutes, your a lot better than I am.

"SQLit" wrote in message
...

"Ignoramus25850" wrote in message
...
I have been playing with using relays of various kinds, as well as
contactors. I already built 2 phase converters, and a remote switch,
for instance. I have a few 90A and 75A contactors and solid state
relays and mag starter buttons and whatnot.

Here's what I have been thinking about. I have a 7 kW Onan DJE
generator that I have for emergencies. I want it to power my entire
house in emergencies (I know that I cannot run AC and some other
devices while under generator power).

It is expensive and painful to install a transfer switch. I want to
make something easier and cheaper to power the house in case of
emergencies, while at the same time preventing backfeeding.

I can, instead of a transfer switch, build a system that includes a
contactor, a mag starter, and a relay that only closes the main
generator contactor when the main circuit breaker is in the OFF
position.

It would work something like this. There will be a mechanical device
and a switch such that the switch could be closed only when the main
breaker is off. When the main breaker is on, the switch could not be
closed.

Where I live the utilities require physcial and electrical interlocks.
Most residential panels do not lend themselves to a physcial interlock.
Square D is the only one that I know of that has a physical interlock
between the main and another breaker.
Then comes to the issue of the equipment being service rated. Then comes
UL
listings.
A contactor/motor starter off the shelf I do not believe is service rated.


There will be a DC circuit, powered by a 9V battery, that would be a
signal input to a solid state crydom relay. The power contacts of the
relay would be in series with the power from generator. When the relay
is closed (only when the mains breaker is open), and a START button is
pressed on the start/stop switch (like ones used for mag starters),
the main contactor would close. The STOP button interrupts input to
the contactor, causing it to open. Turning the little switch near the
main breaker off would also interrupt the circuit, opening the
contactor.

This seems to be a very fool proof system. I can build it in 30
minutes, except that I would need more time to fabricate a mechanical
switch opener/closer.

One piece of advice. I am not seeing it in your description, but I might be
missing it. Do you have a plan for seeing that the incoming power from the
street is back on?

I only mention this as I once had a friend do something similar, and failed
that part. Worse yet, he had to get into his car to drive by a few
neighbors to see if power had been restored. Even worse yet he had to drive
by two of them as they had generators. Remote area it was.

--
Chris

If you can read this, thank a teacher. If it is in English, thank a
soldier. If it is in ebonics, thank your Congressman.

On Tue, 06 Sep 2005 15:42:47 GMT, Ignoramus25850
wrote:

On Tue, 06 Sep 2005 15:30:19 GMT, Toller wrote:
I don't claim to have really followed it, but do know that the contacts on
my TS relay fused closed. Unless your device accomodates that (on the line
contacts) safely, it is no good.

What is a TS relay?

I want to use a large contactor, rated for way more than what my
generator can supply. My genset generates about 28A, whereas the
contactor that I would use is rated for 30A.


You want AT LEAST a 50 amp rated contactor, at 500 volts, for a safety
factor. 30 amps is cutting it a bit fine, since you do not have zero
crossing switching.




i

On Tue, 6 Sep 2005 11:47:41 -0400, "Chris" wrote:


"SQLit" wrote in message
...

"Ignoramus25850" wrote in message
...
I have been playing with using relays of various kinds, as well as
contactors. I already built 2 phase converters, and a remote switch,
for instance. I have a few 90A and 75A contactors and solid state
relays and mag starter buttons and whatnot.

Here's what I have been thinking about. I have a 7 kW Onan DJE
generator that I have for emergencies. I want it to power my entire
house in emergencies (I know that I cannot run AC and some other
devices while under generator power).

It is expensive and painful to install a transfer switch. I want to
make something easier and cheaper to power the house in case of
emergencies, while at the same time preventing backfeeding.

I can, instead of a transfer switch, build a system that includes a
contactor, a mag starter, and a relay that only closes the main
generator contactor when the main circuit breaker is in the OFF
position.

It would work something like this. There will be a mechanical device
and a switch such that the switch could be closed only when the main
breaker is off. When the main breaker is on, the switch could not be
closed.

Where I live the utilities require physcial and electrical interlocks.
Most residential panels do not lend themselves to a physcial interlock.
Square D is the only one that I know of that has a physical interlock
between the main and another breaker.
Then comes to the issue of the equipment being service rated. Then comes
UL
listings.
A contactor/motor starter off the shelf I do not believe is service rated.


There will be a DC circuit, powered by a 9V battery, that would be a
signal input to a solid state crydom relay. The power contacts of the
relay would be in series with the power from generator. When the relay
is closed (only when the mains breaker is open), and a START button is
pressed on the start/stop switch (like ones used for mag starters),
the main contactor would close. The STOP button interrupts input to
the contactor, causing it to open. Turning the little switch near the
main breaker off would also interrupt the circuit, opening the
contactor.

This seems to be a very fool proof system. I can build it in 30
minutes, except that I would need more time to fabricate a mechanical
switch opener/closer.

One piece of advice. I am not seeing it in your description, but I might be
missing it. Do you have a plan for seeing that the incoming power from the
street is back on?

I only mention this as I once had a friend do something similar, and failed
that part. Worse yet, he had to get into his car to drive by a few
neighbors to see if power had been restored. Even worse yet he had to drive
by two of them as they had generators. Remote area it was.
On my brothers recreational property the meter is at the road (with a
disconnect and main breaker) and there is a red pilot lite on the back
of the service box that tells him power is on. His transfer switch is
back at the buildings. When the light is on, he knows the grid is up.

"Ignoramus25850" wrote in message
...
On Tue, 6 Sep 2005 11:47:41 -0400, Chris wrote:

"SQLit" wrote in message
...

"Ignoramus25850" wrote in message
...
I have been playing with using relays of various kinds, as well as
contactors. I already built 2 phase converters, and a remote switch,
for instance. I have a few 90A and 75A contactors and solid state
relays and mag starter buttons and whatnot.

Here's what I have been thinking about. I have a 7 kW Onan DJE
generator that I have for emergencies. I want it to power my entire
house in emergencies (I know that I cannot run AC and some other
devices while under generator power).

It is expensive and painful to install a transfer switch. I want to
make something easier and cheaper to power the house in case of
emergencies, while at the same time preventing backfeeding.

I can, instead of a transfer switch, build a system that includes a
contactor, a mag starter, and a relay that only closes the main
generator contactor when the main circuit breaker is in the OFF
position.

It would work something like this. There will be a mechanical device
and a switch such that the switch could be closed only when the main
breaker is off. When the main breaker is on, the switch could not be
closed.

Where I live the utilities require physcial and electrical interlocks.
Most residential panels do not lend themselves to a physcial interlock.
Square D is the only one that I know of that has a physical interlock
between the main and another breaker.
Then comes to the issue of the equipment being service rated. Then comes
UL
listings.
A contactor/motor starter off the shelf I do not believe is service
rated.


There will be a DC circuit, powered by a 9V battery, that would be a
signal input to a solid state crydom relay. The power contacts of the
relay would be in series with the power from generator. When the relay
is closed (only when the mains breaker is open), and a START button is
pressed on the start/stop switch (like ones used for mag starters),
the main contactor would close. The STOP button interrupts input to
the contactor, causing it to open. Turning the little switch near the
main breaker off would also interrupt the circuit, opening the
contactor.

This seems to be a very fool proof system. I can build it in 30
minutes, except that I would need more time to fabricate a mechanical
switch opener/closer.

One piece of advice. I am not seeing it in your description, but I might
be
missing it. Do you have a plan for seeing that the incoming power from
the
street is back on?

I only mention this as I once had a friend do something similar, and
failed
that part. Worse yet, he had to get into his car to drive by a few
neighbors to see if power had been restored. Even worse yet he had to
drive
by two of them as they had generators. Remote area it was.


Chris, you raised a great question. As of now, I do not have any
provisions for seeing incoming power. I see it as a fully separate
issue from what I am asking, but it is a very good one.

My concern with doing anything to see incoming power, when the mains
breaker is off, is that I would connect an electrical load (a light
bulb perhaps) before the main breaker. That seems a little bit scary.

I could, however, install a little button style light or some such.



Ok just wanted to make sure you had it in mind. I know how we can get.
Focus on one thing and forget the obvious.

--
Chris

If you can read this, thank a teacher. If it is in English, thank a
soldier. If it is in ebonics, thank your Congressman.

"Ignoramus25850" wrote in message
...
On Tue, 06 Sep 2005 15:30:19 GMT, Toller wrote:
I don't claim to have really followed it, but do know that the contacts
on
my TS relay fused closed. Unless your device accomodates that (on the
line
contacts) safely, it is no good.

What is a TS relay?

I want to use a large contactor, rated for way more than what my
generator can supply. My genset generates about 28A, whereas the
contactor that I would use is rated for 30A.

i


Not a good idea at all!!
A transfer switch has to be designed so if it fails it absolutely can not
back feed into the utility power. If your contactor fails closed, and
believe me it does happen, your generator can back feed per to the utility.

I install and service standby generators, if one of our transfer switches
fail there is absolutely no way it will back feed power. The transfer switch
may fail in either position, but no way will it cause a back feed!
Greg