Heating element covers

[elmito]

Any pictures of the "control panel." I'm curious.

 

[Minbari]

sure,

outside:

inside:

 

[Minbari]

ok, so here is what I finally came up with. may not be UL listed, but it does protect the elements from water. Totally water proof. I am sure there are still going to be some that poo-poo it, that is fine

 

[JustLooking]

ok, so here is what I finally came up with.

Did you ever ground the pot? How are you going to clean the pots with the wiring strapped to the table? Will you be changing to flexible cord?

 

[Minbari]

yup, ground strap on both pots.

maybe, but not in the immediate plan. if I find it is impossible to clean it may become a priority. I dont see why I need to pick up the pots to clean them. scrub, PBW over night, scrub, rinse, done. Hate to use a commercial brewery as an example, but they dont pick up or tilt thier kettles to clean them

 

[JustLooking]

Hate to use a commercial brewery as an example, but they dont pick up or tilt thier kettles to clean them

But they would if the could. They use wire rated for a wet environment, and a hose. It's a big PITA and probably the worse job a commercial brewer has to do. To do that on a homebrew scale is just silly (and in your case, dangerous.)

 

[Minbari]

like, I said, its a work in progress and nothing is unchangeable. if this doesnt work, it will get changed to something that does.

 

[kal]

maybe, but not in the immediate plan. if I find it is impossible to clean it may become a priority. I dont see why I need to pick up the pots to clean them. scrub, PBW over night, scrub, rinse, done. Hate to use a commercial brewery as an example, but they dont pick up or tilt thier kettles to clean them

Commercial breweries will use CIP (clean in place) balls and caustic cleaner recirculated with a pump & heated. Unlike your kettles, theirs will have been designed with CIP in mind from the start, including drainage points and what not to be able to drain without leaving standing water. Yours likely has a dip tube/pickup spout and is not bottom drained.

So no, you don't have to pick it up to clean it but it would be considerably easier for you to be able to rinse and drain it sideways since CIP isn't designed into your brewing process from the sounds of it.

Kal

 

[Minbari]

Commercial breweries will use CIP (clean in place) balls and caustic cleaner recirculated with a pump & heated. Unlike your kettles, theirs will have been designed with CIP in mind from the start, including drainage points and what not to be able to drain without leaving standing water. Yours likely has a dip tube/pickup spout and is not bottom drained.

So no, you don't have to pick it up to clean it but it would be considerably easier for you to be able to rinse and drain it sideways since CIP isn't designed into your brewing process from the sounds of it.

Kal

very true. The dip tube does leave behind about 1/4" of water or so. so far I have been soaking that up with a sponge and then air drying.

If I end up re-wiring its not a big deal. flexible cable is available at Lowes. we shall see how it goes on the first couple brews and this setup may get a re-think

 

[jleiii]

The heat is the product of the current through the SSR multiplied by the SSR's voltage drop. The SSR voltage drop is at least half with 120V and since the resistance is constant, the current is half too - so the SSR heat produced is one fourth for the same circuit in 120V instead of 240V.

Not quite on topic for this post, but thought this might be helpful info:

The voltage drop across an SCR (back to back SCR's are the active part of an SSR) is the same regardless of the voltage applied, therefore the heat is a factor only of the current. The voltage drop across the SSR when in full conduction (ie on state) should be the same.
By example, about 1.6 volt drop for a Teccor 25 amp SCR. Multiply this by the current and that is the heat produced. 20 amps at any voltage is the same amount of heat.
No clue if the cheap Chinese SSR's are as efficient.

 

[Minbari]

so I was right the first time 240 volt would produce less heat since it consumes less current in the load.

 

[mattd2]

Not quite on topic for this post, but thought this might be helpful info:

The voltage drop across an SCR (back to back SCR's are the active part of an SSR) is the same regardless of the voltage applied, therefore the heat is a factor only of the current. The voltage drop across the SSR when in full conduction (ie on state) should be the same.
By example, about 1.6 volt drop for a Teccor 25 amp SCR. Multiply this by the current and that is the heat produced. 20 amps at any voltage is the same amount of heat.
No clue if the cheap Chinese SSR's are as efficient.

Makes more sense to me now - checked the Futek Datasheet and it is 1.6V drop.
So a SSR controlling a 5500W element would need to dissipate:
37W of heat @240V when "on" (element power 5500W)
18W of heat @120V when "on" (element power 1375W)
1.2W of heat @240V when "off" (240V drop & 5mA leakage current)

Is that correct? (and therefore I was wrong with the comment of more heat when "blocking" current?)

 

[mattd2]

so I was right the first time 240 volt would produce less heat since it consumes less current in the load.

For a given power yes a higher voltage will be less current (P=IV)
But for a given element (i.e. a set resistance) increasing the voltage will increase the current (V=IR)
So it really depends on how you are looking at it.
Changing from a 2000W @ 120V element to a 200W @ 240V will reduce current. But trying to power a 2000W @ 120V element at 240V will result in more current flow - and more than likely a high risk of electructution/fire due to an overloaded element.

 

[Minbari]

For a given power yes a higher voltage will be less current (P=IV)
But for a given element (i.e. a set resistance) increasing the voltage will increase the current (V=IR)
So it really depends on how you are looking at it.
Changing from a 2000W @ 120V element to a 200W @ 240V will reduce current. But trying to power a 2000W @ 120V element at 240V will result in more current flow - and more than likely a high risk of electructution/fire due to an overloaded element.

well ya, I understand that. (I understand ohms law and watts law) I am not advocating using a 120vac element at 240vac, it would most likely burn up very quickly, being 4x the wattage.

I mean using 3kw of power at 120vac vs 240vac.(using the appropriately rated element) obviously 240vac will be less current. (same power)

 

[Minbari]

Makes more sense to me now - checked the Futek Datasheet and it is 1.6V drop.
So a SSR controlling a 5500W element would need to dissipate:
37W of heat @240V when "on" (element power 5500W)
18W of heat @120V when "on" (element power 1375W)
1.2W of heat @240V when "off" (240V drop & 5mA leakage current)

Is that correct? (and therefore I was wrong with the comment of more heat when "blocking" current?)

yes, active switches are doing essentially nothing when off. weather it is an SCR, Triac, BJT or mosfet. when it is off, it is non-conducting. it is not "blocking" current, it is simply not passing any current. The act of passing current is where the voltage drop comes from. the voltage drop ( V = IR) is where the power dissipation in the device comes from. ( P = IV or P = I*IR, substituting for V or P = I^2*R)

the leakage current is ussually minimal, but something to consider with high voltage.

 

[mattd2]

I mean using 3kw of power at 120vac vs 240vac.(using the appropriately rated element) obviously 240vac will be less current. (same power)

Yeah I had a thought that is what you were meaning. I was just making sure (and for anyone else reading the thread).

 

[atoughram]

Not quite on topic for this post, but thought this might be helpful info:

The voltage drop across an SCR (back to back SCR's are the active part of an SSR) is the same regardless of the voltage applied, therefore the heat is a factor only of the current. The voltage drop across the SSR when in full conduction (ie on state) should be the same.
By example, about 1.6 volt drop for a Teccor 25 amp SCR. Multiply this by the current and that is the heat produced. 20 amps at any voltage is the same amount of heat.
No clue if the cheap Chinese SSR's are as efficient.

I stand corrected - you are correct - the voltage drop over a PN junction is constant. I've got a few Crydom SCR's and they also drop 1.6Vdc while on.

There is also some interesting information on heat dissapation here http://www.crydom.com/en/Products/Catalog/AdvancedWebPage.aspx?CategoryText1=Legacy%20Products&CategoryText2=CSD%20Series%20Legacy%20product%20not%20recommended%20for%20new%20design&SBCatPage=

 

[user 125772]

Sheesh, nuthin like hijacking the thread .
anyway, try Pam cooking spray covers on your element terminals.

 

[Minbari]

Lol, its all good. I like a good discussion, even if a bit OT.

I did finnaly get them covered. I tried the paintcan cover idea, just not good enough. Definitely not water tight