Thread subject: Homeroasters.org :: CoffeeAir II Roaster Build
Posted by seedlings on 08/09/2010 10:50
#1
Wellll, it's a good thing I haven't started any wiring!
My cousin is a master electrician. I'll ask him about it, so he'll know all the local regs. This site says 10 ga is good for 55A:
http://www.powers...e_Size.htm
CHAD
Posted by Dan on 08/09/2010 10:58
#2
"Ampacity" varies with application, regulations, and distance. You read the 'chassis' column. That is VERY short lengths contained within an electrical enclosure. Not the same application as a long run of romex in a wooden structure. There are formulas for calculating ampacity. The nominal ampacities for typical distances in home wiring (according to a wiring handbook) are:
16ga - 10A
14ga - 15A
12ga - 20A
10ga - 30A
8ga - 55A
6ga - 75A
Ask your cousin to verify these for the group. Most states now subscribe to the same building codes. Thanks, Dan
Posted by seedlings on 08/09/2010 11:54
#3
Then I want 10-3 with ground and a two pole 30A breaker. Get a hubble 4 conductor twist-lock outlet and do the wiring inside the roaster, which will be 240V to heaters in series, 120V to the PID and 120V to the blower.
CHAD
Posted by Dan on 08/09/2010 12:20
#4
Sounds like a plan, to me. Make sure your SSR's are rated 220VAC.
Posted by seedlings on 08/15/2010 16:15
#5
Dan wrote:
Sounds like a plan, to me. Make sure your SSR's are rated 220VAC.
I have one 50A 240V SSR.
Here are a bunch of pictures. No new information, just pictures:
CHAD
Posted by allenb on 08/15/2010 17:55
#6
Looks like you're nearing the finish line!
If you get a moment can you post a sketch showing how you're wiring the 240 through the SSR and on to the elements.
I'm not understanding how the SSR sees 240? I assumed you would just be feeding one of the two hot legs through the SSR in which case the SSR would only be seeing 120V?
Allen
Posted by allenb on 08/15/2010 18:12
#7
I sketched up a block diagram of how I would wire it using one SSR and I guess during the off cycle the SSR does see 240V so I answered my own question.
Never mind.
Allen
Posted by seedlings on 08/16/2010 05:29
#8
Probable schem
CHAD
Posted by dja on 08/16/2010 17:37
#9
have your cousin cabbage onto a short piece of din rail and see if you can get all of your components din rail mountable.
if you don't know what din rail is your cousin will.
David.
Edited by dja on 08/16/2010 17:38
Posted by Unta on 08/16/2010 18:12
#10
Been in the construction industry for the last 15 years, and I've never read/heard the word cabbage used as a verb..
thank you homeroasters.org. Again, my life is better because of you.
sean
Posted by dja on 08/16/2010 20:05
#11
I flunked English!
Posted by Unta on 08/17/2010 00:10
#12
not a knock, just an observation. It made me laugh DJA.
Sean
Posted by RoasterRob on 08/17/2010 00:20
#13
Been in NDT for 20 years and I know a welder called Cabbage, other welders I know by nickname - Troll, Crayfish, Spanky, Clinky, Vege, Tiger, to name a few.
Rob
Posted by Dan on 08/17/2010 11:42
#14
I don't think SSRs come in DIN rail mounts. The reason being that they need to be heat sinked. Perhaps if the heat sink was DIN rail, then you could attach the SSR to that.
Typically, you put fuses on both legs of a 240V power line, the reason being that both are 'hot.' On 120V, you only need a fuse on the hot leg (typically black wire).
Posted by seedlings on 08/17/2010 11:56
#15
Two fuses, thanks, Dan. Since the 50A SSR will only be passing 15A of current, do you think it still needs a heat sink?
CHAD
Posted by Dan on 08/17/2010 12:37
#16
Maybe, maybe not. :) What I would do is bolt it to your metal enclosure with some heat sink grease. That will give it some protection.
Posted by allenb on 08/17/2010 13:10
#17
Chad,
Unless the physical size of the back plate of the 50 amp SSR is MUCH larger than a typical 25 amp then I would recommend some sort of a real finned heat sink unless the panel it's mounting to is pretty thick and, as Dan pointed out, includes heat conducting paste.
Allen
Posted by dja on 08/17/2010 18:27
#18
oops, sorry about that guy's forgot about the need for a heat sink on the SSR.
must not of ate all my lima beans yesterday
David
Posted by dja on 08/19/2010 20:49
#19
Chad; here's a pic of the roast chamber that I showed you back in the winter when I was working on a air roaster. Well all the activity with people building air roasters jogged my creative side and this is the roast chamber now all I need is about 1800 watts of heat and a very strong air source.
Edited by dja on 08/19/2010 20:50
Posted by seedlings on 08/25/2010 12:18
#20
OK, I have some cash on hand, and picked up the 10-3 w/g, breaker, high-current switches, etc, to get back on track!
However, I'm a little stumped on the specific type of internal fuse holder I should use. What I can find are just AGC-type fuse holders like in the automotive stores. I'm not sure 15A of 220V would be wise through those... one loose terminal and that plastic will melt quick.
Suggestions? (cheap suggestions)
CHAD