Post by John Shelley on Apr 30, 2015 10:05:45 GMT -5
This fan is a rather special project, actually I had been planning on doing this for a long time I first got the idea way back in 2007 or 8 when I first saw the burnt up 120V Elmo washing machine motor in the motor shop... See these Elmo motors have an 18Pole low speed winding, much like a ceiling fan motor, but most of them are 208-240 but with this one being 120V I knew it could be used as a fan motor easily. So finally earlier this year I got a chance to rewind it, it's got rather odd set up using 54 slots with the windings set up like 3 phase delta motor, as opposed to the 2 phase V that newer K55s and many FASCOs used. Yes I said those are 2 phase because both windings in them have the same number of turns, unlike most single phase motors where the start and run windings are electrically different. But that is a topic for another day, with this motor I only redid the low speed winding since the its either 2 or 4 pole high speed one would have been useless in a ceiling fan motor.
I also had to come up with mounting hardware, due to how big this motor was I went with 1in ID pipe for the downrod, keep in mind that blender fans have 1/2in ID and originals 3/4in ID down rods, so this one is massive. Obviously the large size meant that I needed to use something custom for the 'pivot' in this case, a pipe cap welded to a U joint that in turn was welded to a 3/16 thick steel plate. For the motor end of the down rod I went with a pipe flange and some steel straps, making that connection similar to blender fans or FASCOs but much stronger.
For the flywheel I used a 5-1/2 in x 1/2 aluminum disc that I had friend machine, it is deigned so it could have been bolted onto a standard LAU interchangeable hub but in this case rather than boring out one of those hubs to fit the metric motor shaft we instead modified the pulley that had been on this motor to act like one of those hubs. By modified I mean drilling and tapping 3 holes in it in the same patter as the bolt hols of a LAU hub. The blades for this fan are 6 Hampton Bay industrial blades, I went with those simply because, A I had 2 extra sets and B I knew this motor had so much power that anything less would not be using it to it's full potential.
For speed control I went with a 7.5 amp variac, that is plenty of margin for a 3.8 amp motor. Yeah it uses a lot of power but it also moves a ton of air with the top speed of 330 rpm, that is a lot considering that this fan has 6 blades, 56in diameter, and those bands are aggressively curved, and on top of that are pitched slightly steeper than normal, wind noise wise though even at full speed it remains very quiet.
I also had to come up with mounting hardware, due to how big this motor was I went with 1in ID pipe for the downrod, keep in mind that blender fans have 1/2in ID and originals 3/4in ID down rods, so this one is massive. Obviously the large size meant that I needed to use something custom for the 'pivot' in this case, a pipe cap welded to a U joint that in turn was welded to a 3/16 thick steel plate. For the motor end of the down rod I went with a pipe flange and some steel straps, making that connection similar to blender fans or FASCOs but much stronger.
For the flywheel I used a 5-1/2 in x 1/2 aluminum disc that I had friend machine, it is deigned so it could have been bolted onto a standard LAU interchangeable hub but in this case rather than boring out one of those hubs to fit the metric motor shaft we instead modified the pulley that had been on this motor to act like one of those hubs. By modified I mean drilling and tapping 3 holes in it in the same patter as the bolt hols of a LAU hub. The blades for this fan are 6 Hampton Bay industrial blades, I went with those simply because, A I had 2 extra sets and B I knew this motor had so much power that anything less would not be using it to it's full potential.
For speed control I went with a 7.5 amp variac, that is plenty of margin for a 3.8 amp motor. Yeah it uses a lot of power but it also moves a ton of air with the top speed of 330 rpm, that is a lot considering that this fan has 6 blades, 56in diameter, and those bands are aggressively curved, and on top of that are pitched slightly steeper than normal, wind noise wise though even at full speed it remains very quiet.
