Can i connect 2 inverters together?

Some things to clarify:
Is the battery a 12volt or 24volt? I will assume a 12volt.
You should always have a fuse between the battery and the inverter. The fuse rating and wiring between the battery and your inverter depend upon the size of the load you will hook up to your inverter.
Inverters are usually NOT 100% efficient. Typically they are 80-90% efficient. If you run an inverter at rated load (your case 3000watts), you will most likely damage the inverter. If you run the 3000watt rated inverter at 500watts or less, you will have significant internal losses.
The capacity of the battery is important.
The type of battery is important (Flooded, Gel or GSM).
A 12volt battery is usually fully charged at 14 volts, but as it discharges, the voltage will drop. Batteries should not be operated at less than 11volts and most likely be damaged permanently if allowed to go below 10.5volts.
If a battery is rated at 100 amp/hours, that means it can supply 100 amps of current at 12volts for 1 hour, or 50 amps for 2 hours or 10 amps for 10 hours.
Now for the more important part. Assume your inverter is 80% efficient. 3000 x .8 = 2400. So the maximum load your inverter can safely handle is 2400watts. At 120volts you will be drawing about 20 amps of current at full load.
If you are going to draw full load, your battery must be able to supply the current to that inverter at an equivalent power rating (power out + power loss = power in). Therefore, 3000watts ÷ 12volts = 250 amps. If your load is only 1000watts (80%), load plus loss will be 1250watts, and therefore, the battery will need to supply 1250 ÷ 12volts = 104 amps. Why is this important? Because the wire between the battery and the inverter must be capable of carrying that current. And that becomes even more important, because if the wire carrying that current is undersized, it could start a fire. Also, with Direct Current, there is more of a loss than with Alternating Current. So if your battery is 20 feet from your inverter, it will incur twice the loss if it was only 10 feet away. You may have to use some very large gauge wire to satisfy the requirements.

no statement at all its use;. sure a BOAT, got you there,
how is this inverter connected on both ends.
one end is DC other is AC out. right>?
12vdc input (the big red/black wires) not reversed nor fuse blow, to these pair.
the output is a large AC power jack pure sign wave AC power. it does, means can run computers and things that hate cheap chopper type inverters.

why did you say connected to shore power(AC)
that is not its purpose or job ever. that.
its purpose is to convert, DC battery power to AC POWER
at up to 1200VA (watts)
that is about enough power to run a toaster.(almost)

do not ever connect shore 120VAC power to that large connector on the front of this inverter or you will blow it straight to H3LL
and worse a fire.
the jack there is marked OUTPUT, so connecting short AC output to inverter output is super wrong and dangerous.
I can tell you shore power will win the bucking war here,
boom fuse blows, fire, and smoke can happen., and will. 1 or all 3.

answer 2: connected right (per makers web site see it)?
battery main boat not dead or just disharged. 12.6vdc is good, less bad.
AC jack output on inverter works with say a desk lamp 120VAC 100watts , if not the inverter fuses blow or bad inverter.
some you can hear it sing, ear to casing. (inverter oscillator inside)

Not likely as low voltage should shut the inverter down. Check your battery anyway. 13.5vdc fully charged and each cell that is bad is about 2.25vdc off that. Sounds like the inverter has had an internal failure and unless you are an electronics tech, beyond your capabilities to repair without serious training.

A 1000 watt power inverter hooks to the battery terminals directly, not through the cigarette lighter.

I looked at the power requirements of this projector, 280W, but that assumes a nice sine wave. Your inverted is supposed to put out 400W, but it's a modified sine wave. Under ideal conditions (including a good battery) this might be just enough. Connecting directly to the battery will help a little, because of the limited ability to get current to and through the cigarette lighter. Using a 100 foot extension cord will diminish the voltage a bit (less so if it's a heavy gage wire). I would try connecting the inverter directly to the battery, run the engine and skip the extension cord. If that works, turn off the engine. If that works, try the extension cord. If it won't work with the engine running, connected directly and no cord - there are two possibilities: (1) the projector just won't run on a modified sine wave, (2) you need a bigger inverter. --- regarding (1) I have seen lots of people having trouble with various devices. You might want to ask Epson support. --- Good luck!

DO NOT DO THIS! If I understand you correctly you want to have three ways to have 110 power in your motor home--- (1)Vehicle 12V to inverter to main panel. (2)Generator to main panel. (3)plug the main panel into 110V. If any two of these are connected at the same time and they are both live, somethings going to blow. That's because with AC, the two sources must be synchronized in their cycles very precisely. The utility company connects their power plants together on the grid only with the aid of precise controls. But the really serious problem is the same reason they invented transfers switches for home generators -- if you were connected to (3) and the power went out, and you connected (1) or (2) without disconnecting the dead (3), you will backfeed power to the line outside and you just might kill the lineman who is trying to fix the power outage.

Question does not seem to match this inverters capability.

INFO:
This Power Inverter converts vehicle’s 12-volt DC power into household 115-volt AC power. AC and USB outlets power and/or recharge personal electronics.

We have owned one of these Power inverters for over a year now and have run a great deal with it, from TV to drill press PC and any thing that was small and that could run from my car. Very nice product.

SET UP: Connect wires. ensure correct polarity, push button on top. Plug in 110 volt appliance.

Hope this tip was of some use.

R/
David

Inverters normaly have inbuilt protection built into them check for reset button/switch.

You are definitely on the right track. When you choose your power inverter consider the following: buy the inverter for around 40% more of your anticiapted load. You will need a double pole transfer switch to isolate the inverter from the generator(and visa versa). A simple double throw double pole switch with fuse or breaker protection should do it. You wouldn't necessarily have to isolate the curbside circuit as the double pole double throw switch would simply be switching the power from the existing generator to your new inverter for only the roadside circuit; i.e. you don't need to worry about the curbside power source as it will always be connected to the other branch circuit. Even if your generator or other source came on the system would be protected no matter what the the roadside configuration was set to as only one source of the 2 roadside power sources would be connected at any give time to the roadside circuit. The six dots represent the connecions for the double pole, double throw switch; shown supplying the new inverter to the roadside circuit while the source from the existing generator or inverter is disconnected via this switch from the roadside circuit:

existing * *------* new power inverter; switched to source
* *------*
^
Middle 2 dots represent your roadside circuit and represent the "throw arm" of the switch. Safe and simple! If you don't have a voltage meter for your batteries you can purchase one for a few bucks. Just run it across the terminals so you will know battery condition as it is being drained (you may already have this indicator) You can find a transfer switch at an electrical supply place, maybe even Lowes. Make sure you get the switch that will be in a protected enclosre. The enclosurre can be purchased seperately if you can't find the switch/enclosure package together.

Good luck....gary

Hello Stephen The first thing you have to do is make sure that the motor is connected for 220 volt three phase How do you know? your motor must have this connection info on the name plate It must show 220v Delta connection and 380 or 400 v star connection. connect your motor in Delta ie the motor connection links are connected from U 1 to V2, U1 to W2 and V1 to U2. Ok Now for the restof it You have asmall book that came with the inverter so go to page 9 and you will see the drawing for mm440 at the bottom you will see the connection for the speed pot. which is 1,2,3,4, wire in as shown make sure the wiping connection is in 3..now wire in a switch across 9 which is the common and 5 this starts and runs the inverter when you open the switch the inverter will ramp down and stop.... IF YOU look at page 8 it shows how delta and star is connected at the motor..... now go to page12 for this you must have the power on to the inverter.. as you enter the parameters they come up in sequence as you enter the info...on par 700 put in 2 also at 1000 put in 2 set p1080 at 0.0...p 1082 at 50 P3900 at1 This should get you up and going
Sean Reihill