3 phase kiln questions?

[HappyHippyDad]

A customer has asked me to install a supply for a Wenger Webcot kiln.

The faceplate is very worn and I cannot see the kW. They state the kiln it type 3670w and is rated at 12kW.

The paperwork does have 3670w on it but when I look at the spec sheet (see picture 2, SpecSheet) ) there is no sign of a kiln which is 12kW. This model has 12 elements therefore it must be one of the last 6 models on the spec sheet, but again no sign of 3670w. It looks like there is one called 3060w though but this is not 12kW. Does anyone have any ideas how I could find the kW, or does anyone recognise the kiln details and know the kW?

The wiring diagram (see picture 4) shows that it can be wired as single phase or 3 phase. This will be wired as single phase. My questions...

1. Do I just join the 3 phases together as per the diagram?
2. Do I need to increase cable size compared to the existing flex on the Kiln as I am joining 3 x 10mm cables into one conductor? Although the neutral carries the same current and there is only 1 neutral conductor! Why is this?
3. On the spec sheet (pic 2) it has 2 columns for electricity supply required. One for single phase and one for 3 phase. The last 4 columns for single phase have a dot. looking below it says treat as nominal rating 14kW for single phase, yet the actual column labelled nominal electrical .loading states different, higher values, why is this?

Pictures below show the almost unreadable faceplate, spec sheet, cable and part of the wiring diagram.

Picture 1, faceplate.


Picture 2, Spec sheet.


Picture 3, Cable


Picture 4

 

[westward10]

Try measuring the resistance of the elements.
What csa is the flex currently connected to it.

 

[HappyHippyDad]

Try measuring the resistance of the elements.
What csa is the flex currently connected to it.

The existing flex is 5 core 10mm2, although this is a guess. It certainly isn't 6mm and doesn't look big enough to be 16mm.

Measuring the resistance of the elements to what Westward? I'm guessing this will help in determining the kW, but do I use 400v or 230V in the calculation? I will get varying current depending on which is used.

I can just feel myself asking silly questions now. ?

 

[pc1966]

I suspect you will need to wire larger 3-core to its internal terminals as if wired single-phase the neutral will be a lot more than 3-phase!

If it is quite old then take care in case it has asbestos thermal insulation inside.

 

[pc1966]

OK 10mm is promising, but as @westward10 suggest check the resistances (both star and delta if you like, but it will be running as parallel arms of star)

 

[westward10]

Use the ohm scale of a multi-meter we can then probably establish its load for 230 or 415v.

 

[SparkySy]

If you take the side panel off the kiln there will be the connection terminals for the elements you can measure the resistance of them there to determine the output. The neutral may be for the control side of it. In my sister's kiln the thermostat and timer function are single phase but elements can be wired as either single or 3 phase with links in the connection panel.
It could well be 12-14kw!
Sy
Thinking on it again I replaced the elements on my sister's kiln a couple of years ago and they were 3kw per element and 4 in total.

 

[Darkwood]

As above you need to measure every element, do not assume they are all the same and ensure they are fully disconnected so you do not get parallel readings (depends on wiring config).

A full pic of the wiring plan would be ideal as oppose to the just the connection points, this will establish how the element wiring is arranged, I am working on a 3ph hot plate atm and it has 6 elements at 7.5 ohms and 2 at 11 ohms, it has 2 sets of 3 elements of 7.5 in series to give 22.5 ohms across 400v ph 1 and 2 and one set of 2 elements of 11 ohms giving 22 ohms ph 3 to balance 8 elements over 3 phase. (of course 3ph goes into 12 easier than into my 8 so would expect your elements are all the same rating)

I suspect without further info you have a 8.5kw or 9.5 kw thus at 230v it is ma 9.5kw and at 400 v 3ph it is 3kw per phase. I guess this by the number of elements and the fact you have the option of 230v or 400v according to the schematic.

 

[HappyHippyDad]

OK 10mm is promising, but as @westward10 suggest check the resistances (both star and delta if you like, but it will be running as parallel arms of star)

Use the ohm scale of a multi-meter we can then probably establish its load for 230 or 415v.

If you take the side panel off the kiln there will be the connection terminals for the elements you can measure the resistance of them there to determine the output. The neutral may be for the control side of it. In my sister's kiln the thermostat and timer function are single phase but elements can be wired as either single or 3 phase with links in the connection panel.
It could well be 12-14kw!
Sy
Thinking on it again I replaced the elements on my sister's kiln a couple of years ago and they were 3kw per element and 4 in total.

I must apologise for my lack of knowledge here. I have no knowledge of 3 phase as it is not something I ever work with.

What exactly am I measuring between to obtain resistance values?

 

[pc1966]

With it switched on, do the 6 measurements:

1. (delta) L1-L2
2. (delta) L2-L3
3. (delta) L3-L1
4. (star) L1-N
5. (star) L2-N
6. (star) L3-N

 

[Darkwood]

The elements should have 2 ends, disconnect from wiring and measure with ohms range the resistance across the element, you will get a value then we can chew on and establish what rating we are looking at.

 

[SparkySy]

Inside the terminal panel you should see depending on the kiln the ends of the elements terminated sometimes with a bolt through a porcelain insulator or porcelain terminal block. If you disconnect the ends to it at the terminal block you can measure the resistance to work out the kw.

 

[loz2754]

Maybe give these people a call?

Wenger webcot | Kilncare | Made in Britain

We are the true Wnger Webcot kiln specialist with details and specification from everything from replacement elements to switch gear and controllers.

www.kilncare.co.uk

"We have details, knowledge and specifications for just about every kiln made by Webcot and later, Wenger before Wenger kilns ceased in late 1982. We are truly Wenger Webcot specialists in every manner."

 

[Darkwood]

With it switched on, do the 6 measurements:

1. (delta) L1-L2
2. (delta) L2-L3
3. (delta) L3-L1
4. (star) L1-N
5. (star) L2-N
6. (star) L3-N

Did you read his last post, he is asking how to measure resistance of the elements and you have instructed him to do a live test for this???? ... unless he wants to blow his meter up this is not a good idea, be clear what you mean especially when live testing please.

 

[HappyHippyDad]

Did you read his last post, he is asking how to measure resistance of the elements and you have instructed him to do a live test for this???? ... unless he wants to blow his meter up this is not a good idea, be clear what you mean especially when live testing please.

I'm guessing PC just meant to have the on button on, not actually live.