LnL Quad Element Question?

[not a bot]

Hi,

 I am wondering if you add the Quad Element Option to an LnL e23T-3 or e23M-3 Easy Kiln, does it increase the current requirement of the kiln?

 Does the controller have a specific current regulation circuit or is the current simply regulated by the resistance of the heating elements?

 Are the extra elements wired in some combination of series parallel configurations so the controller sees a resistance similar to the standard configuration?

Thank you very much for any insights you may share.

Thank you.

 

 

[Bill Kielb]

Kilns work for the most part off utility supplied AC mains voltage. So the power of the kiln is usually designed with a fixed amount of wattage which means the elements combined or singularly must total a certain fixed resistance to achieve that wattage. The kiln controller simply cycles the elements on at varying rates to achieve the desired heating ramp rate. This was discussed in the SSR thread. When ordering elements for a kiln, generally operating voltage and model number are required so the element manufacture can provide the appropriate ratted wattage elements. So in the end a kiln will have a fixed wattage design and the combined resistance of all the elements will create the appropriate resistance and therefore draw the specified maximum current when all elements are on. 

A kiln rated at 10000 watts at 240v will draw approximately 41.67 amps and have a total combined element resistance of approximately 5.76 ohms. Elements sized for this example will always be 10000 w @ a rated voltage which determines the fixed resistance they will be provided at regardless of type.

Edited June 26, 2022 by Bill Kielb

[not a bot]

Hi,

 Thank you for explaining, for providing the I=V/R example, and for citing the 5.76ohm figure.

 I have discounted my initial question about the parallel series hookup configurations. It was not well thought out.

I would like to provide some additional context for my question. 

 My question is based on an admittedly imagined premise that the uncoiled length of the element wiring is doubled when optioning the quad element package. If the length of the elements wiring is actually doubled it seems possible that the segments could be wired into the circuit to present an overall doubling of the resistance.

Seeing as how the elements are functionally wire resistors, rather than arbitrarily sized and easily substituted film capsules, and their length is more or less specified to match the form factor of the kiln,  it occurred to me that there must be some strategy to  provide the increased length of the Quad Element Option while accommodating the electrical circuit. 

For example; the resistance of one length of wire can be matched to another wire twice its length by increasing the diameter of the longer wire by a factor of 1.414, so that would be one way to accommodate the circuit.

I am wondering what LnL does to implement their Quad Element installation. They seem very thorough with their engineering and I would like to have a chance to appreciate the choices they have made.

 Thank you!!! 

 

 

 

.

Edited June 26, 2022 by not a bot

[Bill Kielb]

1 hour ago, not a bot said:

For example; the resistance of one length of wire can be matched to another wire twice its length by increasing the diameter of the longer wire by a factor of 1.414, so that would be one way to accommodate the circuit.

I am wondering what LnL does to implement their Quad Element installation. They seem very thorough with their engineering and I would like to have a chance to appreciate the choices they have made.

Yes, you are correct, maybe a combination of element resistance per inch and / or diameter of the wind, diameter of the wire, pitch its wound at- combination of all or maybe something I am not thinking of. As you study elements and learn more there is a design component called element loading which translates basically to total length of element in the kiln and it’s relationship to longevity.

Since you are aware of ohms law, the critical constant for the product is really one of selling you a kiln with a certain amount of wattage or heating energy. (Prox. Watts X 3.41, if you prefer think to about it as Btuh). This establishes the thermal and electrical performance as a constant for a given kiln design. Kilns are designed with about 110% -120% excess energy new.

It would be interesting if you could vet out all the design considerations for the quad elements. I am guessing that their improved radiation profile may be part of it as well. Most heating is done by radiation, then conduction and very little convection so I am guessing it may influence the design.

My guess: One strategy probably encompasses a whole bunch of tested design characteristics on the part of L&L engineers / designers. One thing that should be constant though is the maximum wattage it was designed for, else electrically it can become an issue. The overall resistance becomes one of the constraints and have at it boys and girls for a better (practical) design.

Edited June 26, 2022 by Bill Kielb

[neilestrick]

13 hours ago, not a bot said:

I am wondering if you add the Quad Element Option to an LnL e23T-3 or e23M-3 Easy Kiln, does it increase the current requirement of the kiln?

The Quad elements pull the same current as the regular elements, and are wired the same (parallel on most models). It's all about the length and thickness of the element wire. The option is worth the extra cost, as it will pay for itself in the long run. With typical elements we typically see  a lifespan of130-150 firings when doing bisque and cone 6. With the Quad elements we typically see a lifespan of at least 250 firings. I've seen them go 300, and I've got a customer who says they've gone 350+. Break even on the higher cost of replacement elements is about 240 firings if you're doing the work yourself. If you're paying a repair tech to do the work you'll save a lot of money since there will be fewer element changes.

[not a bot]

Thank you Neil.

You and Bill have been incredibly helpful.