AC change over switch ?

[coventrylad]

Hello every one, please bear with me on this one, Here goes. I have a 3kw generator connected to my sterling pro combi inverter(24 volt) My battery bank is conected to the inverter,and also to a dc consumer unit. the AC from the inverter goes to my AC consumer unit. my 180 amp engine driven alt is conected to the batery bank( six 110amp batts, 24 volt) every thing works fine, some one has thrown a spanner in the works, or should I say my mind ! and said I should have an AC change over switch to change from genny to inverter, Why ? I can not see why I should need one . Am I missing somthing here ? thank you very much. Please be carfull with me.

[Ark Right]

Hello every one, please bear with me on this one, Here goes. I have a 3kw generator connected to my sterling pro combi inverter(24 volt) My battery bank is conected to the inverter,and also to a dc consumer unit. the AC from the inverter goes to my AC consumer unit. my 180 amp engine driven alt is conected to the batery bank( six 110amp batts, 24 volt) every thing works fine, some one has thrown a spanner in the works, or should I say my mind ! and said I should have an AC change over switch to change from genny to inverter, Why ? I can not see why I should need one . Am I missing somthing here ? thank you very much. Please be carfull with me.

 

A very gentle No is the answer.

A

[Happy Go Lucky]

Hello every one, please bear with me on this one, Here goes. I have a 3kw generator connected to my sterling pro combi inverter(24 volt) My battery bank is conected to the inverter,and also to a dc consumer unit. the AC from the inverter goes to my AC consumer unit. my 180 amp engine driven alt is conected to the batery bank( six 110amp batts, 24 volt) every thing works fine, some one has thrown a spanner in the works, or should I say my mind ! and said I should have an AC change over switch to change from genny to inverter, Why ? I can not see why I should need one . Am I missing somthing here ? thank you very much. Please be carfull with me.

 

As your inverter and charger are the same unit I wouldn't fit a changeover switch. They are useful when you have a separate charger as it would be silly to run this off the inverter output or if you have a separate inverter that mustn't be connected to the generator output. I would be tempted to have an isolator switch on the generator output so that the engine speed can settle down before you connect it to the combi unit.

[Robbo]

Don't you have a shore power connection (even if you don't need) You'll need some kind of switch for genny/shore if you do.

 

As for your question my Victron combi is setup like yours, the main benefit is that it will power boost the generator or shore if demand needs it.

[coventrylad]

Thank you both for the replys. I could not see the point of one with my set up, but as I said some one said I should have

[Teadaemon]

There are a number of new checks in part 3 of the BSS (electrical systems), they are only advisory, but are good practise nonetheless. I think the relevant one in this situation would be 3.9.1 "Is it impossible to connect simultaneously more than one power source to the alternating current distribution system?" This does not apply to synchronised multiple power sources.

 

As in your situation the generator is plugged into the inverter, which is then connected to the AC distribution system, I would strongly suspect that either the power sources are synchronised, or when the generator is on the inverter is off and the generator output passes straight through. Exactly how your system works can probably be found in the manual for your inverter. Providing there are no other inputs to the AC distribution system, and the inverter behaves in one of the two ways I've previously outlined, then it should pass that particular check. Come BSS time, it would probably be a good idea to have the relevant manual to hand to show the examiner, in case they're not familiar with your particular model of inverter.

 

Edited to add:

 

I've found the relevant datasheet (I think): http://www.sterling-power.com/images/downloads/ProCombi.pdf

 

It would appear that this unit uses a 'pass-through', so when the generator is on, the inverter is off.

Edited November 29, 2012 by Teadaemon

[by'eck]

Your Combi is a combined charger and inverter, hence the name. It is not (just) an inverter.

 

A Combi's most useful feature is that when AC power is applied to the unit as a whole, from shore or generator source, it will pass through to the same output connections as its inverter, whilst simultaneously powering its battery charger. When the AC source is removed it can automatically switch over to its inverter to maintain the supply to any AC devices connected to its output.

 

Calling Combi's inverters, only confuses people and may have lead to the suggestion you need an AC changeover switch, which would have been valid with a standalone inverter.

[Gibbo]

The simple answer is that you already have one. It's built into your Sterling combi. That's what a combi is: an inverter, a charger and an automatic AC changeover switch.

[coventrylad]

Once again thank you one and all for your help .