[RE-wrenches] Looking for remote controlled contactors

Jason Szumlanski jason at floridasolardesigngroup.com
Wed Oct 12 08:18:46 PDT 2022


Ask any HVAC tech how many 240V contractors they replaced this week alone
on condenser units. They carry boxES on their trucks around here. Granted,
those are engaged far more frequently than in a PV system application,
enduring many cycles per day. But it's still not a failsafe solution.

In my opinion, a PV shedding contactor must only be able to fail in the
open position.

Jason


On Wed, Oct 12, 2022, 11:06 AM Drake Chamberlin via RE-wrenches <
re-wrenches at lists.re-wrenches.org> wrote:

> I haven't had problems with contactors failing. I suspect that a lot of
> the problems on battery systems happen when contactors are controlled at
> battery voltage.
>
> The nominal voltage of the system is not what the coil will see. A 48 VDC
> coil might experience 63 VDC. A resistor needs to be put in series with the
> coil to prevent over voltage. It's value needs to be calculated so that it
> will function, within tolerance, at both the maximum high and minimum low
> voltages.
>
> A 240 V AC contactor coil, on the output of the generator, is quite
> reliable. The voltage it sees is within tolerance and the coil is generally
> not activated for extended periods (days or weeks or even years at a time).
>
> Drake
>
>
> Drake Chamberlin
>
> Athens Electric LLC
>
> Ohio Electrical Contractor’s License 44810
>
> CO Master Electrician’s License 4526
>
> NABCEP Certified PV Installation Professional
> ---
>
>
>
> On 2022-10-12 07:42, Kirk Herander via RE-wrenches wrote:
>
> You are correct on this.
>
> The failure of any control hardware, IO's / relays / contactor logic
> along the way from generator sense to PV contactor should result in the
> coupled grid-tie PV inverter disconnected. Which means the contactor at the
> PV inverter should be energized "closed" (so PV AC connected normally open)
> under normal operation (genny off, PV on).
>
> Wired as such, It can be done with off the shelf components, and remotely
> by adding some controlbyweb.com controllers.
>
>
> On Tue, Oct 11, 2022 at 7:49 PM Jason Szumlanski via RE-wrenches <
> re-wrenches at lists.re-wrenches.org> wrote:
>
> I'm not a fan of this strategy because it is not failsafe. Contactors
> fail. When the coil fails to open the contactor, you will have the PV AC
> coupled with the generator If he normally closed contactor is used in this
> manner.
>
> I think the question needs to be the converse: How do you turn the PV on
> remotely only when the generator is not running.
>
> Jason Szumlanski
> Florida Solar Design Group
>
>
>
>
>
> On Tue, Oct 11, 2022, 2:45 PM Maverick Brown via RE-wrenches <
> re-wrenches at lists.re-wrenches.org> wrote:
>
> I'll usually use  a 60 amp contactor with 240Vac coil.
>
> The generator powers the coil and opens the Normally Closed contacts
> disconnecting the grid tie inverter.
>
> Maverick Brown
> Off-Grid Solar Commander since 2006
> *Maverick Solar Enterprises, Inc.*
> * • Solar Commander Remote Power*
>
> * • SunFlow Systems Cathodic Protection *maverick at mavericksolar.com
> 512-460-9825
>
>
> On Oct 11, 2022, at 11:26 AM, Kirk Herander via RE-wrenches <
> re-wrenches at lists.re-wrenches.org> wrote:
>
> Hi,
> I'm looking for suggestions on a remote control 60 amp contactor. It can
> either be true wireless or send a signal down an AC power line to open /
> close contact at the other end.
>
> I'm trying to figure out a non-wired way to turn an AC coupled inverter
> off when the generator is running, as advised by outback and others.
>
> All suggestions welcome thank you.
> --
>
> *Kirk Herander / **kirkh at vermont.solar <kirkh at vermont.solar>*
>
> *Owner|Principal, VT Solar, LLC*
>
> *Celebrating our 31st Anniversary 1991-2022!!*
>
> *www.vermont.solar*
> <https://nam02.safelinks.protection.outlook.com/?url=www.vermontsolarnow.com&data=02%7C01%7C%7C9f0330d75a244870112408d685311841%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636842843233477645&sdata=0NjyuKeQbEK6245SNnk8X4XnP9Q%2B%2BqtvcALkdDghvk4%3D&reserved=0>
>
> dba Vermont Solar Engineering
>
> 802.863.1202
> _______________________________________________
>
> _______________________________________________
> List sponsored by Redwood Alliance
>
> Pay optional member dues here: http://re-wrenches.org
>
> List Address: RE-wrenches at lists.re-wrenches.org
>
> Change listserver email address & settings:
> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>
> There are two list archives for searching. When one doesn't work, try the
> other:
> https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/
> http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
>
> List rules & etiquette:
> http://www.re-wrenches.org/etiquette.htm
>
> Check out or update participant bios:
> http://www.members.re-wrenches.org
>
>
>
> --
>
> *Kirk Herander / **kirkh at vermont.solar <kirkh at vermont.solar>*
>
> *Owner|Principal, VT Solar, LLC*
>
> *Celebrating our 31st Anniversary 1991-2022!!*
>
> *www.vermont.solar*
> <https://nam02.safelinks.protection.outlook.com/?url=www.vermontsolarnow.com&data=02%7C01%7C%7C9f0330d75a244870112408d685311841%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636842843233477645&sdata=0NjyuKeQbEK6245SNnk8X4XnP9Q%2B%2BqtvcALkdDghvk4%3D&reserved=0>
>
> dba Vermont Solar Engineering
>
> 802.863.1202
>
> _______________________________________________
> List sponsored by Redwood Alliance
>
> Pay optional member dues here: http://re-wrenches.org
>
> List Address: RE-wrenches at lists.re-wrenches.org
>
> Change listserver email address & settings:
> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>
> There are two list archives for searching. When one doesn't work, try the
> other:
> https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/
> http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
>
> List rules & etiquette:
> http://www.re-wrenches.org/etiquette.htm
>
> Check out or update participant bios:
> http://www.members.re-wrenches.org
>
> _______________________________________________
> List sponsored by Redwood Alliance
>
> Pay optional member dues here: http://re-wrenches.org
>
> List Address: RE-wrenches at lists.re-wrenches.org
>
> Change listserver email address & settings:
> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>
> There are two list archives for searching. When one doesn't work, try the
> other:
> https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/
> http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
>
> List rules & etiquette:
> http://www.re-wrenches.org/etiquette.htm
>
> Check out or update participant bios:
> http://www.members.re-wrenches.org
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org/attachments/20221012/07cc2dfe/attachment.htm>


More information about the RE-wrenches mailing list