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Bus Discussion => Bus Topics ( click here for quick start! ) => Topic started by: wal1809 on July 31, 2011, 05:08:30 AM

Title: Electrical?
Post by: wal1809 on July 31, 2011, 05:08:30 AM
I bought a 12 volt fan for the remote mounted radiator on my generator.  For working and testing I have just clipped the wires to the battery.  Now that I am completing the job where should I tap into the gen power to have the fan shut off and on with the gen?
Title: Re: Electrical?
Post by: wal1809 on July 31, 2011, 05:52:14 AM
I am guessing I can run it right off the back of the alternator with the protection of a fuse?
Title: Re: Electrical?
Post by: luvrbus on July 31, 2011, 06:34:38 AM
You really want the fan to be a 110v squirrel cage type with a least 2 speeds the 12v automotive fans for that app is not going to cut it for a remote mount radiator

good luck
Title: Re: Electrical?
Post by: demodriver on July 31, 2011, 07:54:43 AM
http://www.speedwaymotors.com/search-910-64028.html (http://www.speedwaymotors.com/search-910-64028.html)

Once again this is somethign you may concider but several companys offer these and they can be picked up your local parts store.

Luvrbus, What kind of cfm does the fan that you are suggesting have?  The 12 volt ones that use on race cars can pull over 800 cfm. 
Title: Re: Electrical?
Post by: Sean on July 31, 2011, 08:00:19 AM
Quote from: wal1809 on July 31, 2011, 05:52:14 AM
I am guessing I can run it right off the back of the alternator with the protection of a fuse?

No, because if your generator has a 12v alternator on it, that alternator really should be feeding a battery, such as a separate battery for starting the unit.  So connecting the fan there will have it running full time, and running the battery down.

I'm with Clifford on this -- you really want a 120-VAC fan.  In which case, you simply connect it to the generator main output by way of an individual breaker appropriately sized for the fan.  However, if you really want to try to run with the 12v fan, you have two options:

1.  Connect it directly to the battery/alternator setup by means of a 120-VAC relay.  Connect the relay coil to the main generator output through a small breaker.

2.  Connect it to the 12v "run" circuit of the generator wiring, assuming that circuit is large enough to handle the load.  You'll need the wiring diagram for the genny to find this; it usually runs through the safety switches (temp and oil pressure) and then on to the fuel solenoid.

-Sean
http://OurOdyssey.BlogSpot.com (http://ourodyssey.blogspot.com)
Title: Re: Electrical?
Post by: wal1809 on July 31, 2011, 09:19:39 AM
Thank you fellas.  Luvrbus I went to harbor freight and northern tool amd neither had a squirrel cage fan that was large enough.  I am going to try this one on theroad today and see what happens.

It would be easier with the 110 v as there is a plug right there.  I can still change it pretty fast as I made the face where the fan mounts to the box removable by way of a minute and a screw gun.  I can easily redo that face plate while leaving the rest of the box alone.
Title: Re: Electrical?
Post by: luvrbus on July 31, 2011, 09:24:51 AM
WW Grainger they have a large selection Wayne

good luck
Title: Re: Electrical?
Post by: rv_safetyman on July 31, 2011, 10:01:54 AM
One of the problems I have found with the typical 12 V fan is that are rated to deliver a lot of CFM, but they are generally not good at dealing with "static pressure".  If there is any resistance to flow, their performance goes way down.  When you are parked, the static pressure might be manageable, but under mobile conditions, the issue can become huge.

The guru for generators and generator installations is Dick Wright.  He has gone out of his way to help the bus community get their generators installed properly.  At almost every bus rally, Dick presents at least one very informative seminar.  He can supply you a fan that will do the job properly. 

http://www.wricointernational.com/ (http://www.wricointernational.com/)

There are lots of places to cut corners, but generator installation should not be one of them if you  rely on them from comfort.

Jim
Title: Re: Electrical?
Post by: wal1809 on July 31, 2011, 11:42:03 AM
RV I know exactly what you mean.  When my gen dies the bus gets over 100 inside within minutes.
Title: Re: Electrical?
Post by: TomC on July 31, 2011, 09:43:37 PM
I used a single inlet squirrel cage blower belt driven from Grainger.  The radiator mounts to the suction side and the exhaust is out the side under the drivers seat.  1/2hp totally enclosed fan cooled 2 spd motor.  On low it is practically silent. On high will cool at 107 degrees- hottest I've been in with the bus.  Good Luck, TomC
Title: Re: Electrical?
Post by: wal1809 on August 01, 2011, 06:31:52 AM
God love them folks at Grainger but their prices are higher than a cat's #$$.  I just figured out all of the blower fans I have been researching online that are in the $100 to $200 dollar range are "Without a motor".  Sombrero I believe I am going to find me another blower.