Ancient Outback Inverter Questions

[Ron Swanson]

I thought I would ask this here since this is where the smart guys are anyway.

I have a new job/new customer with a pair of FX2024s.  Never even seen these before, they are from about 2003.

There may be a problem with the upper one but we have not gotten that far yet.

They are stacked as you would normally expect to find for 240V output, no transformer auto or otherwise.

The upper (presumably original) one outputs to phase B on the panel and the lower (added later from used stock) outputs to phase A.

They are not exactly the same as the network and BTS jack on the upper face to the left on a little daughterboard so it runs straight out the grommet, while the connectors on the lower face toward you when you take off the smoked glass off a main board.  Maybe this is a clue as to vintage/revision level?

There is a Mate/Mate2 on the upper one directly plugged in, the lower has no network and there is no Hub.

The funny thing is there is 0VAC between phase A and B but they are both outputting 120VAC to neutral.  Phase B has no loads connected to it at present, have not determined why this was done yet.

So the main question is, how are they locked in-phase like this, when there is no network between them and no physical connection other than neutral and ground?

What manual should I be reading for these old things?

Any things I should know from the smart guys?

[boB]

As we remember, you normally use a HUB and 1 Mate to configure the master and slave FX's and one of the pairs of
wires in the cable going from inverter A (the master) to inverter B (the slave) synchronize the two phases and another
pair of communications wires will communicate the voltage and current and information displayed to the MATE hooked
up to the HUB.
Inverter A would be selected as single phase L1 master and inverter B would be selected as the L2 slave which
tells inverter B (slave, L2) to invert its' phase 180 degrees.  They must both be "in phase" so that would be
why you would be seeing 0 volts between A and B (L1 & L2) HOTs.   If you did not have a cable between the two
inverters, then I would assume that both inverters would be running at their own frequency and sometimes you would
see greater than 0 volts between A and B as the frequency/phase changes slightly on their own.

If there is no network connection between the two inverters, then they cannot work in a master/phase relation.

The only work-around that I can think of would be to use the mate on one inverter at a time and program it for
the proper master/slave programming.  Then, unplug the mate and use the cable to connect the two inverters
together using their network jacks and "maybe" that connection would synchronize them together.

I cannot guarantee that this will work though and it has been many years since I've worked with the OB system.

Without a HUB, you would not be able to use the Mate though and would be working blindly.

I suggest that you buy a hub and the cables if they are still available.  I'm not sure if the new mate works
with the old OB gear ?  I think it does.

boB

[Robin]

All you need is the Hub4, not the Hub10.

[Ron Swanson]

As we remember, you normally use a HUB and 1 Mate to configure the master and slave FX's and one of the pairs of
wires in the cable going from inverter A (the master) to inverter B (the slave) synchronize the two phases and another
pair of communications wires will communicate the voltage and current and information displayed to the MATE hooked
up to the HUB.
Inverter A would be selected as single phase L1 master and inverter B would be selected as the L2 slave which
tells inverter B (slave, L2) to invert its' phase 180 degrees.  They must both be "in phase" so that would be
why you would be seeing 0 volts between A and B (L1 & L2) HOTs.   If you did not have a cable between the two
inverters, then I would assume that both inverters would be running at their own frequency and sometimes you would
see greater than 0 volts between A and B as the frequency/phase changes slightly on their own.

Everything you wrote makes sense but somebody thought that there may have possibly been some other means of sync on these old inverters.

I take it you are saying that is not so, I must have just measured them when they were both in phase.  But I find that strange because difference between phase A and phase B was zero volts AC, not one or two volts but flat ZERO and no physical connection, I could see that with my own eyes.

I believe I have a Hub4 here on the shelf, but I just want to double check that these old units use the same basic communications system as the later models?  Once I figure out how this place was supposed to be wired I will go back and revamp things the way they are supposed to be.

And yes, I can confirm that your work around does work on later FXs, all they need is some comm between the two of them to sync phasing, even a failed Hub will still pass the phasing signal.

[boB]

Ron, if both inverter are "in phase" then you will measure 0 volts ac between their two hot terminals.

But usually what will happen is that they will drift in phase and you would measure something and eventually
240 VAC between them.  Oh, IF the neutrals were not tied together then you would see 0 voltage also
since they are both floating (isolated).

Maybe that was it ?

boB

[Ron Swanson]

Both neutrals are tied to a bus bar but the hots are connected to opposite phases of a load center and the network port of the lower unit is not connected to anything.

I thought there may have been an alternative method of phasing that I could not see on these old units but now I do not understand what I am seeing.

[Vic]

Hi Ron,

I know nothing of the OB inverters,   you may already be a member of the OB Forum,   but,   if not,  here should be the Link:

http://www.outbackpower.com/forum/

FWIW,  Good Luck  Vic