Generator: 115 / 220vac at the Same Time

[ViribusUnitis]

Originally Posted by Lancerbye

Sorry I couldn't leave it alone. Most boats and cars do actually have 3 Phase generators in them. They are often called altenators. LOL You can make small ac systems by removing the rectifiers and wiring them either Delta or wye configuration.

Yes, but they're nothing compared to the "3phase" systems that are installed in machine shops, or for high power electrical motors. Let's not muddy the waters by being overly precise! And almost certanly nothing like any 3 phase powered dive compressor!

[Lancerbye]

Originally Posted by ViribusUnitis

Yes, but they're nothing compared to the "3phase" systems that are installed in machine shops, or for high power electrical motors. Let's not muddy the waters by being overly precise! And almost certanly nothing like any 3 phase powered dive compressor!

Ya I know about those systems. Most were 600v 3 phase but if you needed real power , you went to 4160v 3 phase. I was an Industrial Electrician in a past life. Three phase systems can be achieved with a single phase system in various ways.

[Jeannius]

Originally Posted by chris smith

correction , 2.2 kw compressor motor. 220v motor. How many amps will this draw ?

What Hz does the compressor require? If it is 60 then it might work with the L1 and L2 legs producing 240v but, if the compressor expects 50Hz then it is a European/Australian spec which is 220-240v down just one leg.


Just spotted that Dockhead has already pointed this out.

[Pete7]

Those bauers are nice little compressors and far better than the Italian equivalent. Why not just change the electric motor for a 110v type with a similar hp output? an industrial electric motor won't be that expensive.

Pete

[chala]

Originally Posted by ViribusUnitis

Typicaly the only reason to have 3 phase current is with VERY large electric motors.

WEG used to manufacture simple and strong 3-phase motor as small than 0.16 HP.
50 Hz motor at 60 Hz. ABB quote a starting torque reduction of 30% and running torque reduction of 17 %. Also compressor may pump more and wear out faster. Check with manufacturers.

[s/v Jedi]

The Danfoss compressor in your fridge runs on 3-phase power... how many HP is that?

There was a link to an old post of me earlier in this thread but let me repeat this here: the best thing to do is take a "floating" 220V out of the genset and connect that to a Victron auto transformer. This will create a double 110V system with that 220V also available. The big difference with this setup is that you do not have to balance the 110V loads perfectly over the two. It also means you have all the power of the genset available and never overload a winding.

ciao!
Nick.

[chala]

Originally Posted by s/v Jedi

The Danfoss compressor in your fridge runs on 3-phase power
ciao!
Nick.

May be but do not try to connect it to a 3-phase main power.

Originally Posted by s/v Jedi

how many HP is that?
ciao!
Nick.

It depend if you use metric (736 W) or imperial (746 W) HP. A bd35f at 3000 rpm, 0 deg. Celsius is rated at 74.8 W.

[Overlord]

These are my generators specs

Electrical Characteristics Ratings Engine
Model Volts Amps Hertz Phase Wire Power Factor KW RPM Start
7.6 BTD-614* 120/240v 63.3amps/31.6amps 60 Hertz 1800 rpm
* Adjustable to 50 or 60 Hertz. Consult factory for 120/240 volt application.
5.7 BTD-514* 230v 24.7 amps 50 hertz 1500 rpm

My current dive compressor motor is 230v 50hz 2.2kw 2760 RPM
Any ideas of what motor i can replace this with that will do the job and that the 7.6 westerbeke can handle

Thanks

[chala]

First: what is the present output voltage of your generator 240V or 120V? Abviously to run the electric motor of your above compressor you require a 240 volt 50Hz output. Compressor normally start unloaded so they do not create excessive starting current. Your generator looks like it is rated at 5.7kW and your compressor motor 2.2kW if it was me with a correct voltage I give a try but be ready to disconnect the load if anything was to stall.

[Lancerbye]

By the specs you have supplied, you have everything you need to make it work. Tap out the 230 volts install a 230 volt breaker, and a recepticle for your compressor.

[Capn Morgan]

Inside the control box of the generator you will probably find a 120/240 connection, switch or something like that. You will have to select which one you want. Then, you tap power from L1-L2. There will be 240 volts between them. The problem is how to achieve 50Hz as this is critical for an electric motor. You may have to govern the engine down to achieve this, not sure on the Westerbeke. In the old specs of the Bauer Junior it said that the inrush (starting load) was in the region of 40amps, I think you will need a breaker bigger than this to be able to start it.

[s/v Jedi]

Yes, measure the RPM's (with cheap strobe). If you see 1800 RPM, you will have to adjust the governor so that it runs 1500 RPM. You can also see 3600 RPM which you adjust to 3000 RPM (the compact gensets)

Most voltage regulators also need to know if there's 50 or 60Hz. They have a jumper for this when they support both (around where the 120/240V jumpers are)

cheers,
Nick.

[Overlord]

At the moment its 7.6 kw @ 1800 rpm , 60Hz. I want to keep it that way and get a 240v 60 Hz motor for my compressor.At the moment i have a 230v 50Hz motor.
If i keep present motor , i will have to run the generator at 1500rpm and 50Hz. That means i cant run my battery charger/inverter , water heater etc

[Lancerbye]

I have often run 50Hz motors on 60Hz with no adverse effect other then being a little faster. Remember that if you drop your gen frequency down you will also lose voltage unless you have a good AVR as part of your generator. This is an option on mine that was not purchased by the PO. An expensive addition. You should adjust the generator speed using a digital meter that has Hz as a function. More accurate than a tach for this purpose.

[Capn Morgan]

Originally Posted by chris smith

At the moment its 7.6 kw @ 1800 rpm , 60Hz. I want to keep it that way and get a 240v 60 Hz motor for my compressor.At the moment i have a 230v 50Hz motor.
If i keep present motor , i will have to run the generator at 1500rpm and 50Hz. That means i cant run my battery charger/inverter , water heater etc

Can't you get a 110V 60Hz motor for the compressor? Seems like the easiest option....