How do I switch my kiln from 3 phase to 1 phase and vise-versa?

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How do I switch my kiln from 3 phase to 1 phase and vise-versa?

On most L&L Kilns this is very easy to do. It is a matter of re-distributing the wires between the kiln fuses or relays and the main powerblock inside the control box.

Kiln Models

On Easy-Fire kilns the elements must be changed also. On Jupiter and DaVinci kilns elements do not need to be changed.

Two section Easy-Fire kilns and the Liberty Belle kiln are not designed to accommodate a 3-pole powerblock so changing them to 3-phase would be difficult but possible.

Dura-Fire kilns are all 1 phase only.

Jupiter manual kilns without 30 amp fuses need completely different control boxes when going from 1 phase to 3 phase, no problem to go from 3 phase to 1 phase though.

Powerblock Wiring Pattern

What is important to remember is that all the kiln circuits after the main powerblock are 1 phase, on both 1 phase and on 3 phase kilns. Being 1 phase, power is carried through the circuit to the elements by just two wires. On all L&L kilns all the circuits originate at the main powerblock. On 3 phase kilns each circuit taps 2 of the three poles on the main powerblock. On 3 phase kilns each pole of the main powerblock is labeled "L1", "L2", or "L3". The circuits on (for example) an E23T 3 phase kiln would go like this: The top section would connect to L1 and L2, the middle section would go to L2 and L3, and the bottom to L1 and L3, (the control circuit always goes to L1 and L2). It makes a pattern so no matter how many kiln sections someone has you can always apply the pattern to the wires that come from the main powerblock (except for the control circuit wires which always go to L1 and L2). Here is the pattern:

L1 Top Section

L2

L2 Next Section down (or bottom section if it is a 2 ring kiln)

L3

L3 Next Section down (or bottom section if it is a 3 ring kiln)

L1

L1 Next Section down (or bottom section if it is a 4 ring kiln)

L2

L2 Next Section down (or bottom section if it is a 5 ring kiln)

L3

L3 Bottom Section if it a 6 ring kiln

L1. The following will help you actually do it:

 

1 phase DaVinci/ Jupiter to 3 phase DaVinci/ Jupiter that has 30 or 50 amp fuses and all automatic Jupiters

  1. Needs a new 3-pole main powerblock if the current one has just 2 poles.

  2. Needs possibly some longer wires to reach down to the 3rd pole of the new main powerblock.
  3. Label the wires as they connect to the left side of the fuses following the pattern above; top wire is L1, next wire down is L2, next wire down is L2 also, next is L3 etc.

  4. Now connect each labeled wire to it's appropriate pole in the main powerblock.
  5. Control circuit and pilot relays circuit if any stays at L1 and L2
  6. Get a new kiln label with the proper electrical info on it

3 phase DaVinci/ Jupiter to 1 phase DaVinci/ Jupiter that has 30 or 50 amp fuses. and all automatic Jupiters

  1. All the top wires in each circuit go to L1 in the main powerblock
  2. All the bottom wires in each circuit go to L2 in the main powerblock
  3. Or vise-versa; top can go to L2, bottom to L1 if necessary
  4. Control circuit and pilot relay circuit if any goes to L1 and L2. Or vise versa here also
  5. Get a new kiln label with the proper electrical info on it

3 phase manual Jupiter without 30 amp fuses to 1 phase manual Jupiter without 30 amp fuses

  1. Label each wire that now goes from the main powerblock to the relays. Start with the top sections relay and label one wire L1 and the other L2- does not matter which is which. Middle relay label wires L2 and L3. Bottom relay label wires L3 and L1
  2. Now connect each labeled wire to it's appropriate pole in the main powerblock.
  3. Get a new kiln label with the proper electrical info on it

1 phase manual Jupiter without 30 amp fuses to 3 phase manual Jupiter without 30 amp fuses.

  1. Needs a new 3 phase control box with relays controlled by the kiln-sitter. If customer is keeping their old kiln-sitter, it is best to mail it in and have the factory inspect it and if it is ok, connect it to the new control box.
  2. Needs possibly new longer Jumper Cords if their old control box has outlets on the bottom of the box rather than on the side of the box. Also whenever replacing Jumper Cords be sure to check the condition of the Jumper Wire (found on pre 2003 JD and J2300 series kilns).

1 phase Easy-Fire to 3 phase Easy-Fire

  1. Needs a new 3-pole main powerblock
  2. Needs possibly a new power wire harness if the existing wires are not long enough.
  3. Label each wire that now goes from the main powerblock to the relays. Start with the top sections relay and label one wire L1 and the other L2- does not matter which is which. Middle relay label wires L2 and L3. Bottom relay label wires L3 and L1
  4. Now connect each labeled wire to it's appropriate pole in the main powerblock.
  5. Control circuit stays at L1 and L2
  6. Get a new kiln label with the proper electrical info on it

3 phase Easy-Fire to 1 phase Easy-Fire

  1. All the black wires in each circuit that go between the relays and the main powerblock go to L1 in the main powerblock
  2. All the white wires in each circuit that go between the relays and the main powerblock go to L2 in the main powerblock
  3. Or vise-versa; white can go to L1 and black to L2 if necessary.
  4. Control circuit goes to L1 and L2. Or vise versa here also
  5. Get a new kiln label with the proper electrical info on it

Changing phase often means pulling more or less amperage. Be sure to check the electrical specs for your kiln as it will be after the change- i.e. if you are changing to 3 phase look for the electrical specs for your kiln as a 3 phase kiln. Be sure your breaker and wire size is large enough. Breaker size is determined by the new amp rating of the kiln, multiplied by 1.25 (125%) and then rounded up to the nearest breaker size. Wire size is tied to the breaker size:

20 amps
12 gauge copper
30 amps 10 gauge copper
40 amps 8 gauge copper
50 amps 6 gauge copper
60 amps 6 gauge copper
70 amps 4 gauge copper
80 amps 3 gauge copper
90 amps 2 gauge copper
100 amps 1 gauge copper
125 amps 1/0 gauge copper (pronounced "one aught")

150 amps 2/0 gauge copper (pronounced "two aught")

175 amps 4/0 gauge copper (pronounced "four aught")

200 amps 250 MCM copper wire (MCM = Thousand Circular Mils)
225 amps   
350 MCM copper wire

Additional Actions to Take

  1. Unplug kiln.
  2. Trace wiring for missing or bad connections.
  3. Check wiring against wiring diagram.
  4. Check for corroded connectors or connectors that have frayed wires. Replace any such connectors.