240v to 208v question

[walta]

OK your diagram will also work just harder for me wrap my head around.

Is your diagram from the manufacture of your transformer? If so, I would certainly use their diagram over my generic.



Walta

 

[Shoreline_]

Holy smokes. I'm no electrician but it seems like there's a lot of directions everyone is sending this guy lol. My cousin is a license electrician up in mass. He could prob figure this thing out. You're going from 3 electrified wires to 2 right? How come you can't hook up 3 wires into one wire for one side of each element and 3 wires into one wire for the other electrified wire for the other side of each element?

 

[vrinner]

Holy smokes. I'm no electrician but it seems like there's a lot of directions everyone is sending this guy lol. My cousin is a license electrician up in mass. He could prob figure this thing out. You're going from 3 electrified wires to 2 right? How come you can't hook up 3 wires into one wire for one side of each element and 3 wires into one wire for the other electrified wire for the other side of each element?

LOL...yeah...there is some conflicting wiring on the transformer but I think if we are using the diagram that I supplied from the manufacture of the my transformer I think it's hooked up right.

So...the wire in the power cable is 8 gauge, the plug says 6-8 gauge for 50 amps...so I wired it up but not to the kiln just yet.

I checked the voltage on my panel, I put the multimeter to the ACV 600 setting and then touched each probe to each side of the panel where the breakers go and I get 252 to about 260. It fluctuates back and forth.

Now on my transformer and plug wiring, before I plug it in and check the power, I put my meter on continuity check and ground to ground went to zero and ground to black and red did nothing. Then red to black goes to zero...is that right? From the wiring diagram I guess it kind of makes sense but not sure if it's supposed to do that...like maybe something is crossed.

 

[wyliesdiesels]

Holy smokes. I'm no electrician but it seems like there's a lot of directions everyone is sending this guy lol. My cousin is a license electrician up in mass. He could prob figure this thing out. You're going from 3 electrified wires to 2 right? How come you can't hook up 3 wires into one wire for one side of each element and 3 wires into one wire for the other electrified wire for the other side of each element?

Because of ohms law

 

[wyliesdiesels]

LOL...yeah...there is some conflicting wiring on the transformer but I think if we are using the diagram that I supplied from the manufacture of the my transformer I think it's hooked up right.

So...the wire in the power cable is 8 gauge, the plug says 6-8 gauge for 50 amps...so I wired it up but not to the kiln just yet.

I checked the voltage on my panel, I put the multimeter to the ACV 600 setting and then touched each probe to each side of the panel where the breakers go and I get 252 to about 260. It fluctuates back

wow thats pretty high for nominal 240v service. typically a 5% variance in either direction is the standard most PoCos use, so 228v to 252. I would call your PoCo and ask them to check that out...bucking 260v will get you about 228v so its a bit high for something rated 208v

and forth.

Now on my transformer and plug wiring, before I plug it in and check the power, I put my meter on continuity check and ground to ground went to zero and ground to black and red did nothing. Then red to black goes to zero...is that right? From the wiring diagram I guess it kind of makes sense but not sure if it's supposed to do that...like maybe something is crossed.

no thats not right. you shouldnt have a dead short between the 2 ends of a coil.

 

[wyliesdiesels]

Note more likely than not your input voltage will be more than 240 volts by as much as 10% so you start at 264 and end at as much as 229 if it is that high, we could use both transformers to reduce it by another 16 or 32 volts



Please measure and post your supply voltage.

Walta

10% variance on a nominal 240v service is really high (216v to 264v). all the PoCos ive had, had a 5% variance and anything higher or lower was out of spec and required them to adjust things at the substation.

 

[wyliesdiesels]

It looks to me like your diagram and wiring is wrong.

See this diagram note there is a 50% chance my diagram will boost instead of bucking. In other words, there is a 50% chance you will input 240 volts and have an output 272 volts as opposed to the 208 you are looking for. You want to test the transformer with the kiln disconnected to avoid the possibility of damage to the kiln. If you measure more voltage than you expected reverse the wires on X1 and X4.



Walta

his diagram is correct. he needs diagram I as ive previously explained.

 

[vrinner]

not sure which chart youre looking at but its incorrect for bucking 240 down to 208.

according to page 10, he needs to use figure I for bucking, which is found on page 17

So L1 goes to H4 and L2 goes to X1

Then connect H3 to H2 and X3 to X2

His load wires go to H4 and H1/X4

So I noticed on my multimeter that just turning it to the 600 setting without anything touching it's reading 22-23. When I move the dial around there is always some numbers already there. I found a cheap Harbor Freight Cen-Tech multimeter and the dial is zero. Put that up to the panel and it reads 238-239.

OK...so I believe based on my drawing below and the previous pictures of the actual wires and wire nuts I put on, that this picture is correct per the wiring diagram and wyliesdiesels comments. The pointy ends of the wires have the wire nuts on them.

My logic tells me that;

• L1 goes through H4 all the way to H1
• L2 goes through X1 all the way to X4
• If H1 and X4 are wire nutted together, wouldn't that mean that L1 and L2 get connected (dead shorted)?

 

[MBfreak]

Many japanese CNC machines from the 80/90s operate on 3-phase 200 V supply. And often fed from a 3 phase transformer connected at 240 upt to 690 V, with taps available.
Possible to find cheap, since newer machines do not need them.

Ola

 

[fitter30]

Electric elements are all single phase. Just need to be be wired in parallel.

 

[walta]

Now on my transformer and plug wiring, before I plug it in and check the power, I put my meter on continuity check and ground to ground went to zero and ground to black and red did nothing.

Perfect

Then red to black goes to zero...is that right?

I think this is likely a good reading. I would expect something like more than 6 ohm and less than 25 ohms but given the quality of the meters you are using they may not be accurate so close to zero.

As much as I hate to say it the free harbor freight meter may be the better of the two meters.

Safety note before you plug in the transformer turn off the breaker then plug in the transformer. Turn on the breaker while wearing a leather glove and standing to the side of the panel and looking away from the panel and transfomer when you turn it on for the first time with the kiln disconnected.

I would expect to hear some humming from the transformer them measure the voltage that will go to the kiln.

 

[vrinner]

Well I've had that meter since I was a kid so probably time to invest in something a little better. LOL.

I'll give it a shot as per your instructions and hopefully not a "shock". Will report back voltage.

 

[wyliesdiesels]

Well I've had that meter since I was a kid so probably time to invest in something a little better. LOL.

I'll give it a shot as per your instructions and hopefully not a "shock". Will report back voltage.

i was gonna say it sounds like you need a new meter

 

[vrinner]

Great news. Plugged in the transformer and read the voltage at 210. No hum from the transformer but obviously doing it's job. Tonight I'll work on the kiln hookup wiring.

 

[ez-duzit]

Attaboy.

 

[vrinner]

Next, we need to move the two wires in the center of the power block.

Let’s add a second red and black dot to those two wires.

Then move the wire with 2 red dots to the where the red arrow is in this photo

Same for the black wire and arrow.

Now the kiln will run on single phase.

Do you have a 240-volt 40-amp receptacle?

Do you have a plug and cord to fit the receptacle?







Walta

Just so I'm clear on these instructions, I'm moving the two dots red to the top one that was previously marked black and then the two dot black to the bottom one that was previously marked red. Again...just making sure.

 

[walta]

When you have it wired for single phase, there will be no wires connected to the center terminal.

Move the wire from the center terminal with the red on it to the top.

Then move the wire from the center terminal with the black on it to the to the bottom.

When you are finished there be wires with both red and black marks on the top screw and there will also be a red and black marked wires on the bottom screw. The red wired run one heater and the black wires run a second heater note there is a third heater but its wires will remain unchanged.

Walta

 

[vrinner]

Houston...the Eagle has landed! Success!

I wired up the kiln to the transformer and plugged it into my existing 40 amp circuit to test and the kiln control panel powered on. I then just did a quick cycle to make sure the heating elements were turning on and they did! I didn't want to run it too long for fear of my existing 40 amp wires not being enough. So this weekend I'll either replace that wiring or just run a second plug. The real test is ramping it up to temperature so hopefully that will all go well.

Thanks again to EVERYONE and especially @walta, @wyliesdiesels for their patience and perseverance through this with me. I absolutely love this forum!

 

[vrinner]

Successful full cycle firing of the kiln. This picture was at about 900 degrees, the full fuse went up to 1480 and it was too hot to open lid and take a picture.

There was a slight issue at first when it would fire it would give me and E-6 error on the controller. Looked up the code and it was thermocouple error. I did notice that the temp was going down instead of up and was going down from like 20 to 0 before the error. I noticed the wires from the thermocouple had + and - marked on them as well as the terminal post they hooked to were - and +, so I switched them correctly and it worked like a charm!

Hopefully the lid will hold up fine as it does have some missing pins (I piled them up in the corner) as well as some missing, what looks like a coating, on the lid but fingers crossed for it working fine long term.

Again...thanks everyone for your help!

 

[ez-duzit]

Attaboy.

 

[Norcal]

Using electric resistance appliances/equipment in CA is a quick way to the poor house, since electric rates are either the highest or close to the highest rates in the country.

 

[vrinner]

Using electric resistance appliances/equipment in CA is a quick way to the poor house, since electric rates are either the highest or close to the highest rates in the country.

I hear ya but I currently have a negative electric bill. This big kiln will only be used for larger projects as I have a smaller for normal use which I have run many times already. Getting A/C in my shop is next on the big electrical usage thing. That will bring my bill above zero for sure.