On 3/16/2012 7:49 PM, gregz wrote:
wrote:
On 3/16/2012 6:45 PM, Oren wrote:
I'm converting a HVAC furnace blower fan (c1997 model) into a garage
shop fan. Salvage from my house. There are no markings, labels, etc.,
on the motor for information. I know nothing about the motor other
than four speeds.

Pic sample: (like this)

http://s.ecrater.com/stores/136988/4b04f808b9c5f_136988n.jpg

The black wire is high speed, the blue wire is low-high speed. The
red and orange wires are high-low or low speed (have not yet connected
/checked).

The high speed (black) gets hot as does the extension cord plugs and
the metal cowling. Putting bigger gauge cords on I still get heat on
the cord, 12 gauge (25'). Same with the blue wire, but not as hot
(metal cowling cool) or as much heat on the cord.

My next try is the high-low speed, same 12 gauge extension cord (25').
Then try the other speed, low, on the same cord.

The motor has a start capacitor; the motor runs fine. Heat on the
cord is what I want to eliminate.

Any thought on using the high speed without the heat problem?

If I have to, I can settle for the lowest speed, but prefer the higher
speed (desert hot garage).

Ideas and help appreciated.


Oren, a furnace fan is normally in a closed structure and the air flow is
restricted by opening sizes. RBM asked you about amp draw as this is
what you need to NOT exceed or you will toast your motor soon. I've made
quite a few of these for different people/reasons. You'll be really
close if you close off one side of the fan with a piece of peg board, the
other side can remain full open. The amp draw will be really close.

Restriction should lessen amps.

Greg

Correct, the current will drop because the motor is doing less work. ^_^

TDD