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CharcoalRoaster
11/04/2019 1:58 AM
+1 snwcmpr

snwcmpr
11/03/2019 2:16 AM
Can we make the shoutbox UNAVAILABLE until a member has a certain number of posts?

allenb
11/01/2019 2:20 AM
Funopt, please post in the gas and electric heat sources forum

Funopt
10/30/2019 5:17 AM
Can someone help me for using forced propane burner as my heating element. I rather want to use lpg than electric. Do you think it would work

snwcmpr
10/22/2019 5:31 AM
Thanks to you all....... I was not sleeping ... I stayed awake worried about it all. :)

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need help finding a digital 220v 20 amp controller
benshot
i want to avoid buying a heavy variac, but i will if i have to. what im doing is building a roaster totally from scratch parts (sheet steal, vac motor, northstar coleman globe), as you can probably guess it will be a fluid bed roaster capable of about a pound of green coffee.

i want to run it on 220 because im thinking it will be about 3000W on 120..not sure what that would be on 220, but i know it's less.

im going to get a permit from the DPA to roast in a commercial kitchen so i can sell my beans at the farmers market.

so i would really like some help finding a digital kiln controller or something. iv'e tried everything in google with very little luck. all i can find is a bunch of dirt cheep controllers from hong kong..should i trust those to work?? especially since i will be using this roaster for large amounts of coffee, im worried that even if i get the 10,000 watt controller which is only $20 that it may still burn out..

also, do you think it's a good idea to use elements from a laundry dryer? or should i use thinner brand new nichrome coil? i have two 1 foot lengths that im planning on putting in series. im not really sure how to calculate how much wattage i will need to roast 1 lbs of coffee.
 
allenb
Ben,

You're in the right ballpark at 3kw for 1 lb fluidbed. This would be around 13-14 amps at 220 V.

Dryer elements work fine for heat but most of them are closer to 5kw which won't be a problem as long as your controller or SSR is rated for the load.

For us to help you with your control questions you need to let us know how you intend to control the roast. Will you want to program ramp segments for time/temp profiles or are you looking to be able to manually control the roast?

Allen
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
oldgearhead
Most controllers are connected to SSRs (Solid State Relays).
It's the SSR that carries the current, and the controller sends low voltage DC to the SSR. I would suggest an industrial grade controller either Fuji or Honeywell that has a manual output (% on signal) option, connected to a 50 amp 220V SSR...
Most Honeywell and Fuji controllers can operate on either 120V or 220V..and they have ramp/soak features if you need it...

A good place for cheaper controllers:
http://www.auberins.com/
Edited by oldgearhead on 06/07/2013 2:11 PM
No oil on my beans...
 
benshot
allenb wrote:

Ben,

You're in the right ballpark at 3kw for 1 lb fluidbed. This would be around 13-14 amps at 220 V.

Dryer elements work fine for heat but most of them are closer to 5kw which won't be a problem as long as your controller or SSR is rated for the load.

For us to help you with your control questions you need to let us know how you intend to control the roast. Will you want to program ramp segments for time/temp profiles or are you looking to be able to manually control the roast?

Allen



i want to be able to control the voltage to the element manually based on temp readings and sense of smell/sight.

i guess it would be cool to eventually make a programmable roaster that would use ramps at preset voltages. but iv'e been roasting with a variac most of my home roaster days. it's what im use to. so if anybody has ideas on both approaches that would be good.

i think i am going to end up having to buy a 220v 20amp variac on ebay for $200. iv'e been thinking and im pretty sure that a "phase angle controller" that could handle 14-20 amps on 220 will cost me at least 200..maybe more. i cant find one to buy anyway.

basically my original intent was to buy a powerful dimmer. direct control over the voltage to the element.

what i wanted to end up with was a roaster that had all the necessary workings and controls built right in, and all of be under 50 lbs. but it's starting to look like im stuck using clunky variacs..

any ideas on what else i could use to vary the voltage?

i wouldn't know the first thing about how to roast with a PID and SSR unless it was a very pricy one that could program ramps and soaks. im on a tight budget with this project and those are too much.

i swear i saw a kiln control modual at some point..if only i could remember what it was called.
 
oldgearhead
benshot wrote:

allenb wrote:

Ben,

You're in the right ballpark at 3kw for 1 lb fluidbed. This would be around 13-14 amps at 220 V.

Dryer elements work fine for heat but most of them are closer to 5kw which won't be a problem as long as your controller or SSR is rated for the load.

For us to help you with your control questions you need to let us know how you intend to control the roast. Will you want to program ramp segments for time/temp profiles or are you looking to be able to manually control the roast?

Allen



i want to be able to control the voltage to the element manually based on temp readings and sense of smell/sight.
>snip<


Any temperature controller with a manual control option connected to an SSR can do this.
If you want 1000 watts set it for 30%, 1500 watts = 50%, and etc.

I suggested a H'well or Fuji so you could experiment with ramp/soak.
But if price is an issue, look at this one:
http://www.auberi...cts_id=106
No ramp/soak but it has manual control mode.
No oil on my beans...
 
oldgearhead
btw - I roast 440 grams of coffee 2-3 times a week using the following watt settings:
1050, 1350, and 1200

I roast 440 grams simply because 456 grams of several beans I use won'y fit in a one-quart Mason jar...
No oil on my beans...
 
benshot
oldgearhead wrote:

btw - I roast 440 grams of coffee 2-3 times a week using the following watt settings:
1050, 1350, and 1200

I roast 440 grams simply because 456 grams of several beans I use won'y fit in a one-quart Mason jar...


wow, seriously? i had no idea you could roast that much at such a low wattage. is this 220? that would explain that..am i right that wattage will be lower on 220 than if the same element was hooked to 120?

not sure what you mean by the percentages. is that referring to on time vs off time, actual percents of line voltage, or how fast the pid come up to the set point. i am very new to pid technology, and as of now i thought their only purpose was to get you up to a set point as fast as possible and maintain it. are you saying that i can use a special kind of pid to control how fast the coffee progresses to a certain temp?

so i should be good to go with elements that are about 2500 watts? but that's in terms of 120v..i have to do some more reading about how 220 behaves in ohms law.
 
oldgearhead
Watts is watts. It's the product of current (amps) x voltage. Most USA homes are feed with 220 volts from the street. This voltage is 'center-tapped' so you have two 120V circuits feeding your service entrance box. The 120V circuits are usually limited to 15 amp and 20 amp outlets. Therefore, 1800 - 2400 watts is considered the max load for USA 120V circuits. However, if you have a 220V 50 amp circuit your limit is the product of 220 x 50.

My roaster reclaims 20-50% of the heat that leaves the roast chamber.
The reclaiming adjustment spans the 420°F - 550°F heat range.

http://forum.home...ad_id=2207
...
oldgearhead attached the following image:
dsc_8390_3.jpg

No oil on my beans...
 
benshot
so i found a few things-

2000w furnace restring kit-

http://www.ebay.com/itm/New-Universal-Furnace-Heating-Element-Restring-Kit-2000W-240V-Free-Shipping-/190843409526?pt=LH_DefaultDomain_0&hash=item2c6f275476

Payne variable voltage controller 5900w capacity-

http://www.newark.com/payne-engineering/18tb-2-25/variable-transformer/dp/95F7100

i originally found one that was rated for 3600..but the 5600w one is only about $10 more, so might as well. that way if ever want to build a 2 lbs roaster, i wont have to buy a stronger controller.

about the element-

so i should be good to roast a pound of green with 2000w at 220?? i want to be sure of this. has anyone on here used much more than that?

my roast chamber is about 5" di, 6" hi. 1 pound of green comes to about a third of that height. ill have a 2" grate at the bottom of the funnel.

im using a vac fan and a bunch of scavenged metal cans. most of it stainless. ill keep looking at the other links you have shared with me, thanks!
 
oldgearhead
I think 'DJA' and 'Seedlings' used two of these:
oldgearhead attached the following image:
861-1633_large_14.jpg

No oil on my beans...
 
benshot
thank yal! ill be posting a new tread in the roaster build forum soon to show and tell about my roaster as i build it. it's a pretty epic design, and 95% from scratch.
 
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