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	FORUM ON BEER, HOMEBREWING, AND RELATED ISSUES
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Contents:
  Re: Pre-chiller: plate or immersion? (Mike Dixon)
  GFCI's ("A.J deLange")
  GFCI internas ("Thomas Rohner")
  MALT Turkey Shoot 2007 (Jack Mowbray)


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Date: Thu, 06 Sep 2007 04:03:42 -0400
From: Mike Dixon <mpdixon at ipass.net>
Subject: Re: Pre-chiller: plate or immersion?

 I think Danny' suggestion for chilling sounds like a good idea. I still 
used an immersion chiller and due to the hot water temps (84F) here in 
NC, we tried an immersion prechiller going to an immersion chiller with 
satisfactory results. It took awhile but were able to cool 12 gallons to 
about 72F. However, that was still a slight bit higher than where I 
wanted to pitch.

Several people use immersion pumps and an ice water recirculation to 
finish chilling the wort after the initial heat is removed. Being 
exceedingly frugal I setup a bottling bucket with a very inexpensive 
drill mounted pump (6.5 gpm for a cost of $5) and after I got the wort 
below 105F (about 12 min on 6 gallons with 84F tap water), I setup the 
drill pump ice water loop and was able to get to 64F a short while 
later. Still not quite my target, but within a hour or two in the fridge 
the batch was ready for pitching.

So if you are using the plate chillers in series, I would chill with one 
plate using tap water, and then the other plate using an ice water 
recirculation. Just use enough water to allow the pump to operate 
properly and the recirculation system will use the least amount of ice. 
My one experience with a plate chiller did not give excellent results so 
I stuck with an immersion chiller.

Cheers,
Mike Dixon
Wake Forest, NC


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Date: Thu, 06 Sep 2007 13:17:00 +0000
From: "A.J deLange" <ajdel at cox.net>
Subject: GFCI's

A couple of thoughts on this subject stimulated by responses to the 
original question:

1. The earthing wire does not go through the GFCI current sensing 
transformer. Thus leakage from hot or neutral to the earthing wire can 
cause a trip. This also means that the GFCI can be used without the 
earthing wire and in fact the NEC allows GFCIs to be used on unearthed 
circuits in some circumstances (406.32(D)(3)(c)). Therefore if the 
heatstick has been wired so that there is leakage to the earth wire 
removing the earth wire may solve the problem. It would be much better 
if the heatstick were repaired so this leakage is not present because 
the earth wire is there to convey fault current back to the source. Take 
it away and there is no path except possibly through the user and now 
the GFCI is being relied upon to protect the user from becoming that path.

2. The test button does work when the earth wire is removed. It switches 
a resistor into the circuit between the load side hot and source side 
neutral.

3. Modern GFCIs are designed to trip if the neutral and earth are joined 
on the load side. Thus if someone should wire earth and neutral together 
at the heatstick or if earth and neutral should come into contact 
somehow a newer GFCI would trip. The neutral and earth must only be 
joined at the service entrance. The wiring for a heatstick (or other 
load) should be phase (hot, black, red, blue) to one side of the 
resistive element, neutral (grounded, white, gray) to the other. The 
earth (grounding, bare, green, green with yellow tracer) wire should 
only be connected to the metallic shell of the device. Note that I have 
used earth and neutral rather than grounding and grounded in the hope 
that this terminology (borrowed from the Brits) will reduce confusion 
regarding the names of these conductors

4. Capacitance leakage can result in imbalance current which can trip a 
GFCI but 6 ma or more capacitative current requires an impedance of 2K 
or less which means about 1.3 ufd capacitance. That's a lot given that 
cables usually run a few pf per foot.

5. A GFCI outlet is often wired as the source for several conventional 
outlets which it can also protect. But any leakage anywhere downstream 
of the current transformer will trip. This often gets to be a real 
nuisance where an interior GFCI feeds outlets in places exposed to 
dampness (garages, crawl spaces) because often the home owner is not 
even aware that there are other outlets in the chain (sometimes you will 
see little "GFCI Protected" stickers on conventional outlets. This is 
clue that these outlets are daisy chained from a GFCI outlet.

6. One can buy "extension cords" with GFCI breakers built in and one 
sometimes finds these "in line" GFCI units in appliances which are used 
in damp locations. One of these for each heatstick may be an approach 
that solves the problem.

A.J.


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Date: Thu, 6 Sep 2007 17:03:01 +0200
From: "Thomas Rohner" <t.rohner at bluewin.ch>
Subject: GFCI internas

Hi again

first about the wiring. The neutral and the grounding of your house are
connected at your main breaker box. So without any load, neutral and ground
should be the same anywhere in your house. Now lets start drawing current at
the end of your installation. If you measure now between the neutral at your
load and ground, you will have a small voltage there. This is because your
neutral isn't a superconductor and therefore has a small resistance. After
Ohms law that's U=R*I, so the higher the current and the resistance, the
higher the voltage.
If for example the neutral in your load (appliance, heatstick) touches
ground somehow, you get quite a current down to ground if its shorted.
That's I=U/R where R is very low in a short circuit, so I can get quite
high, even with U quite small. (For example U=0.3V R=0.1 Ohms you get a
current of 3000mA while the GFCI trips at 20mA or even less)

Now to the working principle of a GFCI. It's somehow like a relay, but then
not. It has a magnetic coil that attracts sort of a plunger that will break
open the two conductors.(and stay open until manually closed again.)
Now the coil is quite special, because it has two insulated windings, wound
parallel. One winding has the current running to the phase through it, the
other the neutral in reverse direction. As long as the current is the same
in both windings, the magnetic fields will be substracted from each other
equalling 0 because of the opposite flow direction of the current. The
breaker won't trip. As soon as the current in both windings isn't the same
anymore, the magnetic field isn't 0 anymore. If the difference is big
enough, the breaker trips.
Thats how it works in principle, as you can see, ground was nowhere in the
equation. But then it is used for the test button, and it wouldn't make any
sense to remove it from the GFCI anyway. Either your heatsticks leak
somewhere, or their neutral gets connected to ground.
If their neutral is connected to ground, the only thing you can do is take a
really thick cable from your main breaker to your heatsticks. Or use
heatsticks that are well insulated. (would be my choice) And make sure that
neutral and ground are not connected together in your heater control
circuit.
I had to learn this the hard way during my education, i was troubleshooting
a heatplate for smd thickfilm cirquits. At some point i had to use a
oscilloscope. I thought well, neutral is the same as ground, so i can
connect the oscilloscopes ground to the neutral of my heatplate. I was
wrong(as you can see in the first paragraph), soon i had some software
developers standing around me with this special sparcle in their eyes.(That
says i could kill you) It turned out that their multiuser developement
system was on the same phase as my heatplate. It wasn't very prudent of them
to use the same phase as us hardware dudes.  I think they changed it after
this incident. At that time,(1985) those developement systems didn't seem to
have a autosave function either. (It was a 68000 with 1Meg Ram and a 40Meg
HD runing on Unix, they had 8 terminals and worked with crosscompilers and
editors. This was quite state of the art back then. That was also the time
when a "home PC" like the C64 had 64kB Ram and a floppy, if you were lucky.)

Cheers Thomas



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Date: Thu, 06 Sep 2007 12:46:17 -0500 (CDT)
From: Jack Mowbray <jmowbray at verizon.net>
Subject: MALT Turkey Shoot 2007

Maryland Ale and Lager Technicians (MALT) are again pleased to 
announce their 3rd Annual Turkey Shoot* Homebrew Competition. 
This will be a BJCP sanctioned event. 

Cash prizes will be awarded for Best of Show as well as for 2nd and 
3rd place. There will be sponsored prizes awarded to individual 
category winners.

The competition will be held Saturday, November 10th at Clipper 
City Brewing Company in Baltimore, MD. All BJCP beer categories 
will be accepted and the deadline for entries is November 3rd.

Additional information, rules, entry forms, and bottle labels can 
be found at the MALT website: http://www.maltclub.org

We could use some more BJCP accredited judges for this event. 
Anyone who is interested in helping with the judging should contact:

Mike McMahon
fishandbrew at comcast.net


*no live poultry will be harmed during this event





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