Generator: 115 / 220vac at the Same Time

[Overlord]

I have a new westerbeke 7.6 D-Net and will replace my old 7.6 Btd. The boat is wired for 115v.I recently bought a Bauer Jnr dive compressor that is 220v.Can i install it with a dedicated 220 v power supply from the genset and be able to use it by switching a breaker/switch.In other words can my genset supply 220v and 115v by throwing a switch ?I will only use the 220v for the compressor and i presume the switch will isolate the 220v poiwer to the wires/supply to the compressor only.
I am all ears sparky's

[David M]

There are generators that can produce both 120 and 240. What are the specs for your generator? You do not need a 1:2 step up transformer if your generator can produce 240. You also want to make sure your generator has the power to operate your dive compressor. As you double your voltage your amps will halve minus the loss from inefficiency from your power supply.

On a 240 volt generator putting together the L1 and L2 legs produce 240.

[Overlord]

Its a 7.6 kw generator,digital.The compressor is a 2.5 kw ,220v motor

[Overlord]

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

[Sand crab]

10 amps but compressors draw more on startup. Ohms law calculator here.
Electrical & Electronics, Ohm's Law, Formulas & Equations
When you double the voltage you halve the amps so you end up with about 34 amps at 220 which should kick the compressor over no problemo provided you have the correct wiring and breaker to it. The crazy thing is that a higher voltage decreases the amps which is the true juice so you can now use smaller wire, In this case 12 ga would be fine. BOB

[Overlord]

Got it .Thanks.Any idea how much more the start up amps are ? Specs on generator sayWire Power Factor KW RPM Start
7.6 EDT-614* 120/240 63.3/31.7 amps 60
* Adjustable to 50 or 60 Hertz.
5.7 EDT-514* 230 24.8 amps 50

[Palarran]

I run my Bauer Junior 220v off a 8kw with no problem at all. Don't worry.

[Sand crab]

Might be up to 50% more amps. See if the compressor states it. A 20 amp 220 breaker should handle it. BOB

[Capn Morgan]

Originally Posted by chris smith

I have a new westerbeke 7.6 D-Net and will replace my old 7.6 Btd. The boat is wired for 115v.I recently bought a Bauer Jnr dive compressor that is 220v.Can i install it with a dedicated 220 v power supply from the genset and be able to use it by switching a breaker/switch.In other words can my genset supply 220v and 115v by throwing a switch ?I will only use the 220v for the compressor and i presume the switch will isolate the 220v poiwer to the wires/supply to the compressor only.
I am all ears sparky's

There is an interesting setup here for 110/220:

http://www.cruisersforum.com/forums/...tem-29667.html

[djmarchand]

It can be done but it will take some rewiring of your boat. The simplest way is to configure your genset to produce 240 volts (wire the two coils in series) with a neutral so also you get 120 betweeen L1 or L2 and neutral. Currently it sounds like your genset is configured where both coils are wired in parallel to produce 120V.

But here is where it gets a little complicated. You now have two 120 systems. Each will produce half of the wattage of the genset. And they can't be paralleled. You have to wire each 120 system independently to your AC distribution panels and keep them separate.

Often an air conditioner is on one system and convenience outlets are on another. The idea is to try to balance the loads between the two 120 volt systems.

It is exactly like what you have on your home AC distribution system.

YOu will also need a 240 V breaker dedicated to your dive compressor.

A good marine electrician should be able to fix you up.

[chala]

Originally Posted by chris smith

In other words can my genset supply 220v and 115v by throwing a switch ?

It all depend what type of voltage regulator your genset is fitted with.
Check with the manufacturer.

[David M]

Chris,
Does your generator natively produce 240 or not? The answer makes a huge difference in how you would make this work.

[Dockhead]

Guys, make sure you consider how many phases. 240v three phase has nothing whatsoever to do with 230v or 220v single phase.

So if the generator natively produces 240v three phase (giving you 120v single phase on either phase), you will not be able to power a 230v single phase (European power) dive compressor. Or vice versa.

[ViribusUnitis]

Dockhead,

240V in the US is NOT 3 phase. 3 phase has 3 hot wires, with each wire exactly 120 degrees out of phase of the other two. It also typicaly has a ground, and a neutral. It is very unusual to find a 3 phase generator on a boat. Typicaly the only reason to have 3 phase current is with VERY large electric motors.

240V in the US has only 2 hot wires. They are both hot, but have the voltage 180 degrees out of phase with each other, so that the differental is 240 volts. It also typicaly has a neutral.

According to the following website, the Westerbeke 7.6 EDT D-NET 7.5 is wired to provide 120 and 240 V US style current. It might already be wired into the boats wireing system, and just require the proper breakers and wireing in the boats main breaker box.

I can't find a specification for dive compressor. Depending on the specs, it might be quite easy. There are apperently 3 phase version, which would be very difficult to wire in. There are single phase 240V versions that might be quite easy, and 120V versions. Depending on which one you have, it could be easy, or hard.

[Lancerbye]

Originally Posted by ViribusUnitis

Dockhead,

240V in the US is NOT 3 phase. 3 phase has 3 hot wires, with each wire exactly 120 degrees out of phase of the other two. It also typicaly has a ground, and a neutral. It is very unusual to find a 3 phase generator on a boat. Typicaly the only reason to have 3 phase current is with VERY large electric motors.

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.