| electric fans (again) checking the math [message #145696] |
Thu, 06 October 2011 09:03  |
hertfordnc
Messages: 1164
Registered: September 2009
Location: East NC
Karma: 0
|
Senior Member |
|
|
First, have we heard form anyone using electric fans successfully? Along with myself, several people indicated they were looking into it it but I don't know if we've heard back from them.
i have one working on the Revcon but it's only been tested at idle-
It comes on at about 185, the temp continues to climb to 195 and then falls back below 185 and the fan cuts out. I have not timed the duration.
I do not know the output of my fan. It came from a list of FWD fords that have huge enormous fans. It's recomnended by the offroad guys.
I have figured out some math- It appears that fans produce about 125 CFM per amp- that's extraploated from the manufacturers numbers on diffferent fans.
So 5000 CFM is around 40 amps.
5000 CFM is about the air movement you would get at 60 mph over one square foot of radiator, right? (5280 ft/ mi, 1 mi/min=5280 CFM? )
I have not been able to figure out how much the clutch fan produces but these numbers might be helpful (if they are correct) in guestimating what might be needed.
Dave
Dave & Ellen Silva
Hertford, NC
76 Birchaven, 1-ton and other stuff
Currently planning the Great american Road Trip Summer 2021
It's gonna take a lot of Adderall to get this thing right.
|
|
|
|
| Re: [GMCnet] electric fans (again) checking the math [message #145698 is a reply to message #145696] |
Thu, 06 October 2011 09:16  |
Dolph Santorine
Messages: 1236
Registered: April 2011
Location: Wheeling, WV
Karma: -41
|
Senior Member |
|
|
I'm still trying to mentally reconcile that on the average car, 40% of the alternator capacity is taken by the radiator fan.
That's a big number. I'm not saying that it's right or wrong, I'm just trying to put it in context of the total load.
Dolph
On Oct 6, 2011, at 10:03 AM, dave silva wrote:
>
>
> First, have we heard form anyone using electric fans successfully? Along with myself, several people indicated they were looking into it it but I don't know if we've heard back from them.
>
> i have one working on the Revcon but it's only been tested at idle-
>
> It comes on at about 185, the temp continues to climb to 195 and then falls back below 185 and the fan cuts out. I have not timed the duration.
>
> I do not know the output of my fan. It came from a list of FWD fords that have huge enormous fans. It's recomnended by the offroad guys.
>
> I have figured out some math- It appears that fans produce about 125 CFM per amp- that's extraploated from the manufacturers numbers on diffferent fans.
>
> So 5000 CFM is around 40 amps.
>
> 5000 CFM is about the air movement you would get at 60 mph over one square foot of radiator, right? (5280 ft/ mi, 1 mi/min=5280 CFM? )
>
> I have not been able to figure out how much the clutch fan produces but these numbers might be helpful (if they are correct) in guestimating what might be needed.
>
>
> Dave
>
> --
> Dave & Ellen Silva
>
> 1972 Revcon Olds 455, toro drive train. All Stock
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
|
|
|
|
| Re: [GMCnet] electric fans (again) checking the math [message #145745 is a reply to message #145698] |
Thu, 06 October 2011 18:36 |
hertfordnc
Messages: 1164
Registered: September 2009
Location: East NC
Karma: 0
|
Senior Member |
|
|
| Dolph Santorine wrote on Thu, 06 October 2011 09:16 |
I'm still trying to mentally reconcile that on the average car, 40% of the alternator capacity is taken by the radiator fan.
That's a big number. I'm not saying that it's right or wrong, I'm just trying to put it in context of the total load.
|
I'm not sure "40%" and "average car" are what we're looking for.
I'm pretty sure that it takes 90 amps to equal the airflow at 60moh across two square feet of unobstructed radiator.
I don't know how that compares with the actual airflow across the whole radiator (5-6 sq feet?)
i don't know if you need that much.
I think if you were grunting up a steep hill in second gear at 25 mph that 10,000 CFM would pretty nice.
I'm just hoping smarter people than me will chime in.
Dave & Ellen Silva
Hertford, NC
76 Birchaven, 1-ton and other stuff
Currently planning the Great american Road Trip Summer 2021
It's gonna take a lot of Adderall to get this thing right.
|
|
|
|
| Re: [GMCnet] electric fans (again) checking the math [message #145746 is a reply to message #145745] |
Thu, 06 October 2011 18:48 |
Dolph Santorine
Messages: 1236
Registered: April 2011
Location: Wheeling, WV
Karma: -41
|
Senior Member |
|
|
Dave
AGREED.... or, I'll finally get something more definitive from the maker.
Dolph
On Oct 6, 2011, at 7:36 PM, dave silva wrote:
>
>
> Dolph Santorine wrote on Thu, 06 October 2011 09:16
>> I'm still trying to mentally reconcile that on the average car, 40% of the alternator capacity is taken by the radiator fan.
>>
>> That's a big number. I'm not saying that it's right or wrong, I'm just trying to put it in context of the total load.
>
> I'm not sure "40%" and "average car" are what we're looking for.
>
> I'm pretty sure that it takes 90 amps to equal the airflow at 60moh across two square feet of unobstructed radiator.
>
> I don't know how that compares with the actual airflow across the whole radiator (5-6 sq feet?)
>
> i don't know if you need that much.
>
> I think if you were grunting up a steep hill in second gear at 25 mph that 10,000 CFM would pretty nice.
>
> I'm just hoping smarter people than me will chime in.
>
>
> --
> Dave & Ellen Silva
>
> 1972 Revcon Olds 455, toro drive train. All Stock
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
|
|
|
|
|
|
|
|
|
|
|
|
| Re: [GMCnet] electric fans (again) checking the math [message #145817 is a reply to message #145807] |
Fri, 07 October 2011 11:16 |
hertfordnc
Messages: 1164
Registered: September 2009
Location: East NC
Karma: 0
|
Senior Member |
|
|
i doubt there's anyone on this board as thick skinned as I am so I'd love to hear your opinion.
This particular discussion has been mostly an exchange of opinions so I thought throwing and actual number at the discussion might be helpful.
I think you can put 10,000 CFM of heat removing air to the radiator for about 1.5 hp and I think that is more efficient than the clutch fan.
It may not be a measurable affect and it may not be as simple and reliable.
Dave & Ellen Silva
Hertford, NC
76 Birchaven, 1-ton and other stuff
Currently planning the Great american Road Trip Summer 2021
It's gonna take a lot of Adderall to get this thing right.
|
|
|
|
| Re: [GMCnet] electric fans (again) checking the math [message #145824 is a reply to message #145817] |
Fri, 07 October 2011 13:26 |
Dolph Santorine
Messages: 1236
Registered: April 2011
Location: Wheeling, WV
Karma: -41
|
Senior Member |
|
|
The 1.5hp is the problem.
That's 1114 watts. The output of a 100 amp alternator is 1,200 watts.
From an efficiency standpoint, you lose some on the alternator side, and some more on the fan motor side.
I'm trying to make sense of it as well, but I have a need to run the A/C condenser when the engine is not running, which is what's leading me to look at this in the first place.
Dolph Santorine
Dolph@DolphSantorine.com
Phone: 304-219-3100
Cell: 740-312-5342
Http://www.DolphSantorine.com
On Oct 7, 2011, at 12:16 PM, dave silva <admin@oldrv.net> wrote:
>
>
> i doubt there's anyone on this board as thick skinned as I am so I'd love to hear your opinion.
>
> This particular discussion has been mostly an exchange of opinions so I thought throwing and actual number at the discussion might be helpful.
>
> I think you can put 10,000 CFM of heat removing air to the radiator for about 1.5 hp and I think that is more efficient than the clutch fan.
>
> It may not be a measurable affect and it may not be as simple and reliable.
>
>
> --
> Dave & Ellen Silva
>
> 1972 Revcon Olds 455, toro drive train. All Stock
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
|
|
|
|
| Re: [GMCnet] electric fans (again) checking the math [message #145826 is a reply to message #145824] |
Fri, 07 October 2011 13:50 |
hertfordnc
Messages: 1164
Registered: September 2009
Location: East NC
Karma: 0
|
Senior Member |
|
|
| Dolph Santorine wrote on Fri, 07 October 2011 13:26 |
The 1.5hp is the problem.
That's 1114 watts. The output of a 100 amp alternator is 1,200 watts.
From an efficiency standpoint, you lose some on the alternator side, and some more on the fan motor side.
I'm trying to make sense of it as well, but I have a need to run the A/C condenser when the engine is not running, which is what's leading me to look at this in the first place.
|
The 100 amp load is max and it's intermittant. The battery might be able to carry the surge.
The efficiency question is whether or not that intermittant 1.5 HP is less than the drag of the clutch fan.
Why do you need to run the AC condenser when the engine is not running? How would that work?
Dave & Ellen Silva
Hertford, NC
76 Birchaven, 1-ton and other stuff
Currently planning the Great american Road Trip Summer 2021
It's gonna take a lot of Adderall to get this thing right.
|
|
|
|
|
|
|
|
GMCforum
Search
Help
Register
Login
Home
