On Wed, Aug 22, 2012 at 7:26 AM, Marty Campanella baypelican@gmail.comwrote:

Hi Marty,

All you need is a relay like this one:
http://www.ebay.com/itm/OMRON-MK2P-I-AC-110V-Relay-8-Pin-10A-250VAC-With-PF083A-Socket-Base-/261078313312http://www.ebay.com/itm/OMRON-MK2P-I-AC-110V-Relay-8-Pin-10A-250VAC-With-PF083A-Socket-Base-/261078313312?pt=LH_DefaultDomain_0&hash=item3cc97ae960#ht_2063wt_948

Wire the coil to the genset output and then use the contacts to control the
fan.

With that said... a few comments:

1. You might want to consider instead a thermostat, which would run the fan
   whenever the ER gets hot. This will keep the fan running after the genset
   shuts down. Bonus is that you don't even need to mess with any 110 volt
   wiring, just put this in line with the fan:
   http://www.homedepot.com/Building-Materials-Heating-Venting-Cooling-Thermostats/h_d1/N-25ecodZ5yc1vZ25ecodZ25ecodZasjhZ12kxZ12ky/R-100400017/h_d2/ProductDisplay?catalogId=10053&langId=-1&keyword=thermostat&storeId=10051#.UDTijtZlQf4

2. Do you have any automatic fire extinguishers (e.g. Fireboy)? If you do,
   then you should rig an auto fan shutdown. Otherwise, the fan will such all
   of the extinguishing agent out of the ER before it can smother the fire.
   You need something like this:
   http://www.fireboy-xintex.com/engine-shutdown.htm

Hope this helps,

Scott Welch
Island Eagle

Scott replied:

(endsnip)

Brent's reply:
I agree with Scott. To trigger it off the genset you just need a relay with
120V trigger (or 240v depending on your genset) that you can wire to the
output of the genset with the switch part wired to your blower. I've bought
these at Grainger, just be sure the contacts are rated high enough for your
fan amperage.

The thermostat is also a great idea, however these little household
thermostat's probably won't handle the current of an er blower. I've used
these thermostats to control little muffin fans for years, but they draw
milliamps. You can still use that thermostat, but have it control the
trigger circuit on a little cube relay (available at Radio shack,
O'Reilleys, etc) and have the relay power the fan. At most A/C supply houses
you can find "cool only" thermostats for around $20. I have these
controlling little fans in my desk where my computer is, and in a settee
where  my inverter is. Work great.

Brent Hodges

The only problem with using a household thermostat is that the highest
temp setting (all of the ones I looked at today at HomeDepot) is only 90
degrees F. Heck, here in Florida with the engine room temp of 85-86
degrees all the time in the summer, the fan would be running shortly
after starting the engine/genset.

Even in northern climates, our engine room temp when underway is usually
at least 110F if the ambient air temp is less than 75F and the water
temp is less than a chilly 60F. The engine room actually makes a good
place to dry wet shoes and clothing (and to warm up after getting soaked
in a squall).

I'd look instead for a non-household thermostat, something with a high
temp of around 110-115 which would be more useful in an engine room when
underway or when running a genset.

You can judge best by checking the temp of your engine room when
underway and getting an appropriate thermostat that you can adjust so it
isn't on constantly (or at least isn't on when you don't want it to be on).

<><><><><><><><><><><><>Mozilla Thunderbird<><><><><><><><><><>
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On 8/22/2012 9:50 AM, Scott Welch wrote:

Snip"...> I would like the blower to come on automatically whenever the
generator is

AC

I installed a Delta T 350cfm continuous duty fan and two additional vents in
the engine room to vent heat to benefit the batteries and inverters.  I
found that the fan had a relatively small effect when cruising as the
engines are pumping air and water that keep temps down.  However, when
stopping after a run (at anchor etc.) all that water and air movement stops
and the engines radiate much more heat than before.  Engine room temps climb
much higher then when running.  My generator does not seem to contribute
that much when running, however when stopped the same heat radiating effect
occurs.  Thus, I turn on my fan when stopping the engines to prevent heat
building up in the engine room.

Joe
Currently docked in Mt Pleasant, WV heading up the Great Kanawha River to
Charleston tomorrow.

M/V "Carolyn Ann" GH N-37
MTOA# 3813
AGLCA# 5485 (Platinum Looper)
http://carolynann-n37.blogspot.com/
Joseph.pica@gmail.com

You might try the thermostat used to turn on the attic fan.

Chuck Hanson

On Aug 22, 2012, at 8:21 PM, Bob McLeran Bob@MVSanderling.net wrote:

On 8/22/2012 7:26 AM, Marty Campanella wrote:

Sure, the simple answer is a relay.  Buy a simple 120 VAC relay and wire
the coil directly into the generator output, (i.e. before the
SHORE-OFF-GEN switch).  Then, wire the contacts in the relay such that
when the relay is energized by the advent of the generator making power,
they close.  This will then apply the 12 volts you wire to the relay to
the blower.  Gen-on = Blower-on.  You could then parallel the contacts
in the switch with your existing switch so that if you want the blower
on but the gen is not running, you manually flip that switch on.  You
could even automate that pretty easy by adding another engine oil
pressure switch dedicated to that function.  That switch would close
when the main engine made oil pressure and once again supply 12 VDC to
the blower.

Ken Bloomfield

On Wed, Aug 22, 2012 at 9:15 PM, Chuck Hanson cr_hanson@yahoo.com wrote:

That is an excellent idea! Plus, these thermostats will handle the current
of a larger fan.

I think I'll try this on Island Eagle.

Scott Welch