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Topic: ac fan controller how to (21 msgs / 473 lines)
1) From: R.N.Kyle
Thanks Mike It looks to be simple enough, even for a dummy like me.
Ron Kyle
Anderson SC
rnkyle

2) From: Mike McGinness
Just got a quick how to put together with pics...http://home.attbi.com/~mdmint/coffee/fancontrolproto.htmHope this helps!
MM;-) aka Kona Konnaisseur miKe mcKoffee
Dual Variable Transformer Rosto Roasting
Rocky grindin' - Miss Silvia brewin'
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3) From: Lowe, David
I sketched up a schematic of what I think you have and I am not sure how =
it really works with the line voltage connected to both sides of the =
transformer. None the less, it obviously works and answers a question =
that I was thinking of posting. Thanks!
Dave Lowe

4) From: AlChemist John
Sometime around 08:48 1/24/2003, Mike McGinness typed:
<Snip>
Thanks mike.  Completely different than I thought.  I am going to try and 
wire it up tomorrow.
--
John Nanci 
AlChemist at large
Roasting and Blending by Gestalt
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5) From: AlChemist John
<Snip>
I had just test wired up everything, it was all a go, so I start striping 
off wire insulation end and caps to make my final connections.  In the 
process of removing the post ring from the fan wire, ready for this, pulled 
it out,  AAAHHH!!!.  Not to be beat this time, I disassemble the whole 
roaster, untaped the coil, found the connections, and coil wire break (glad 
I saw that) and soldered them both back together.  The continuous circuit 
tone on my Fluke has never sounded sooooo good.
Anyway, I can now roast at least 140g in my WBI unassisted.  I  figure if I 
want to play with the heater during the drying stage, I could get it up to 
150-160 g.  Unassisted roasting was the goal, so I will probably be happy 
with almost 5 oz of beans.
Catching the post before sending...
Oh btw, I did have one unintended result of this. I have always known I was 
getting false low temp readings as my thermometer tip was just touching the 
beans.  With more beans in the chamber, my thermometer is in 
deeper.  Correspondingly, I think I am now getting more accurate bean 
temps.  1st and 2nd are occurring at 15-20 F higher than before (apparent, 
of coarse, not real).  I was readying to stop my roast just at 2nd and it 
by passed 425 (which was my 2nd temp) so I just watched.  First 2nd C 
outliers at 450, 2nd at 455.  Seems a bit more in line with MM readings if 
I recall properly.
--
John Nanci 
AlChemist at large
Roasting and Blending by Gestalt
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6) From: floyd burton

7) From: Tom Gramila
On Sun, 26 Jan 2003, AlChemist John wrote:
<Snip>
	I have also benefitted from the ac fan discussion -- I have my WB1
fan running off a variac.  If I boost the fan voltage to 140V I can get
good bean circulation in 180 grams of beans at the start of the roast.  I
tilt the popper to enhance circulation, I can't remember who I got this
pointer from.  I have a 4 or 5 inch chimney, with out this I would lose
alot of beans at the end of the roast, even after backing off to a less
aggressive 115 or 120 volts for the fan. The bean color is very uniform,
even at about 350F, so I think 180 grams is within acceptable range for a
"hopped up" WB1.
<Snip>
	I run my fiberglass TC down the side of the chamber so it reaches
a point 1.5 inches above the bottom.  I initially had alot of variability
in 1st and second crack temps, but got very uniform readings by having a
brass shimstock piece covered with a mica strip both behind the TC wire.  
The brasskeeps the TC from getting blown into the middle of the chamber,
and the mica thermally isolates the TC from the wall. The TC is then
immersed in beans that are falling DOWN.  I think that the air flow is
much lower here, the beans are blowing UP pretty rapidly on the other side
of the chamber.  The first signs of second crack come pretty reliably at
435F over a good variety of beans, regardless of how much airflow I have 
set.
	My next check will be to get my hands on one of the Deward
recommended IR sensors as a real check of whether my thermometry is good.
	It sure is nice to roast 180 grams!
	Tom G.
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8) From: AlChemist John
Sometime around 08:09 AM 1/26/2003, floyd burton typed:
<Snip>
Sorry if I misspoke.  The Fluke is only a multimeter.  The thermometer is 
the dial one from SM.
<Snip>
Nope, never there.  What do they do?
--
John Nanci 
AlChemist at large
Roasting and Blending by Gestalt
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9) From: Mike McGinness
From: "AlChemist John" 
<Snip>
You're welcome. Glad you got it working. Hey, if it wasn't for help from
others I wouldn't have had a clue how to wire such a simple inexpensive fan
controller!
BTW, congrates on fixing your fan wire boo-boo!
MM;-) aka Kona Konnaisseur miKe mcKoffee
Dual Variable Transformer Rosto Roasting
Rocky grindin' - Miss Silvia brewin'
homeroast mailing listhttp://lists.sweetmarias.com/mailman/listinfo/homeroast

10) From: AlChemist John
Sometime around 11:32 AM 1/26/2003, Tom Gramila typed:
<Snip>
I think 160 is going to be my top limit.  It just can't move 180.  I wonder 
what the difference is?  WBI's seem to use stock items.
I tilt the roaster too, although with the transformer bolted on a plate in 
the back, the roaster now has a natural tilt.  Very nice roasting this 
quantity.
--
John Nanci 
AlChemist at large
Roasting and Blending by Gestalt
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11) From: Tom Gramila
On Mon, 27 Jan 2003, AlChemist John wrote:
<Snip>
	Come to think of it, there are two other changes that I have made
to the air path in the popper.  I have the bottom cover off so the fan
motor is exposed, (I sit the popper on a pair of short seperated 2x4's to
make sure the airpath is really open from below)  and have removed the
mica insulator inside the heater section for better airflow through that
section.
	But I have guessed that they would mostly influence the end of the
roast where the flo is high, as opposed to the start of the roast, where
the airflow is relatively low.  I would have thought that at the start of
the roast its the pressure that the fan can generate is what matters most.
					Tom
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12) From: AlChemist John
Sometime around 08:59 AM 1/27/2003, Tom Gramila typed:
<Snip>
Well, I have the bottom off also, plus modified once with a different fan 
blade to increase flow.  Never noticed the mica.
<Snip>
Agreed.  I never could determine how much "backing" the fan needed to 
generate pressure.  I sometimes seems that if I left the roast 6 or so 
inches, the flow drops, but I am not sure.  Any ME's out there to know if 
too much opening behind a fan will lower it's output pressure or CFM under 
load?
--
John Nanci 
AlChemist at large
Roasting and Blending by Gestalt
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13) From: Ken Mary
<Snip>
I would think there are already enough cutouts in the design. Has this
improved airflow?
<Snip>
IMO this is risky. It creates a shock hazard should the heater come into
contact with the aluminum housing. Also, if two widely separated points on
the heater touch the aluminum, you have a short circuit.
--
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14) From: Ken Mary
<Snip>
Fans have an operating curve (airflow vs. static pressure or horsepower)
where they like to run. Too high an airflow will cause some types of fan to
overload the motor. Too low a flow is just wasting energy. Popper or roaster
fans have multiple flow restrictions in the design. Enlarging the free area
at the outside air inlets may have little effect on overall resistance to
airflow.
--
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15) From: Ben Treichel
AlChemist John wrote:
<Snip>
First thought is that it should lower both. The fan is working on the 
compressibility of the fluid to raise its pressure. If you change the 
gap  that the fan works on that should effect performance, i.e. 
efficiency. CFM, more back pressure, less cfm, mass flow, don't ask.
One other thing, its never advisable to choke the input of a fan. Causes 
trouble.
<Snip>
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16) From: Tom Gramila
On Tue, 28 Jan 2003, Ken Mary wrote:
<Snip>
	I never got around to measuring this, since I started exploring 
the over-voltage approach of Mike and Deward, --  and then  needed the hot 
wire anemometer back at work.  I'll see about borrowing it again.
<Snip>
	Agreed, the mica is there for a reason.  I gave its removal a try
after someone here mentioned that theirs disintegrated, without resultant
electrical problems.  If the popper is re-assembled carefully, there is
about 3/16 inch between the outermost part of heater and the aluminum
chamber, and as best as I can see, the aluminum chamber is electrically
isolated. the three screws holding it only reach plastic, and the outer
plastic shell prevents me from touching it.  I do agree that doing this is
a risk, but I have not had any signs of shorts or stray voltages -- I have
been looking for them.
	I'm not sure that this mod is doing much good, but since I can do
180G now, I am reluctant to remove it until I have the time to measure
airflows again.   The removed bottom plate and removed mica happenned 
prior to the high fan voltage discussion.....
Tom G.
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17) From: Tom Gramila
On Tue, 28 Jan 2003, Ken Mary wrote:
<Snip>
	It would appear that there are signicicant pressure drops in the 
rest of the system. I would guess that apart from the beans, the "gate" 
that directs the airflow at the bottom of the chamber is a very 
significant impedence.  
	I have some info on the "fan curve" for the poppery, though it is 
far from complete.  The static pressure the fan can make (no flow 
permitted) is 3.5 in-H2O at 118 V.  If I run the fan at 139V the static 
pressure is increased to 4.1in-H2O.  These are measured by a Dwyer 
magnehelic guage.  I was a bit suprised at how high this is.
	The flow that the UNLOADED popper produces is appx 50 CFM -- that
is no mods, no beans in chamber.  I have no way to measure the pressure 
at the fan under these conditions.
	Interestingly, the pressure at the bottom of the bean mass (with
bottom plate and mica removed) when there is a 180G charge of beans is 1.5
in-H2O, at BOTH 120 and 140 volts. Both the (still unmeasured) flow
clearly increases at 140 V.
	My motivation in removing the mica and bottom plate was to try to 
get as much of the available pressure of the fan to be across the beans 
and the flow "gate".
			Tom G.
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18) From: Tom Gramila
John,
	On Tue, 28 Jan 2003, AlChemist John wrote:
<Snip>
    ^
    Care to say more here?  This is something I have wondered about, since 
the poppery fan blade seems a pretty simple design, I wondered whether 
there might be room for improvement.....
	What sort of a blade did you try????  I would think that a blade
design the was optimized for pressure at a cost of some of the CFM'ss
would fare best, since there is more than enough flow at the end of the 
roast.
			Tom G.
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19) From: Ken Mary
<Snip>
I can offer a few suggestions if you want to play with the design. The WBI
fan has two pieces. I would imagine that removing or swapping the end plate
with a smaller diameter would reduce the pressure and increase flow. If you
want higher pressure (with possibly lower flow?), reduce the clearance
between the blade and the inlet side. Or easier, raise the voltage within
reasonable limits considering the winding temperature. I would not recommend
building a new blade design unless you can balance it.
The factory design may be best for popcorn. For coffee there could be room
for improvement. If time allows, I may try my own suggestions.
--
----------
<Snip>
<Snip>
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20) From: AlChemist John
Sometime around 06:48 1/28/2003, Ken Mary typed:
<Snip>
That was rather what I noticed.  Maybe 5-10%.  I run without a bottom cover 
on my WBI and if I add the cover in the middle of the roast, airflow 
definitely drops.  Something in the back of my mind to try variations 
of:   adding perforations to the bottom roast chamber plate and/or 
converting it to a non-cyclone style fluid bead altogether.  I have 
wondered if one of the limiting factors is the outlet side and that the air 
must be losing some kinetic energy with all of those vector changes.
--
John Nanci 
AlChemist at large
Roasting and Blending by Gestalt
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21) From: AlChemist John
Sometime around 11:00 1/28/2003, Tom Gramila typed:
<Snip>
It is a high temp stiff plastic  angled 5 blade that I got a Johnstone 
Supply.  Again, helped some, but not as much as I had hoped/expected.  I 
believe the original was designed for quite running.
--
John Nanci 
AlChemist at large
Roasting and Blending by Gestalt
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