Hi Folks,

Some of you have seen my recent post of acquiring a rare and beautiful Lady Duchessa lever machine. That thread is here: Lever Espresso Machine Gallery.



Well, she's all dressed up and nowhere to go! The last owner had a 220v converter box installed by engineers at her workplace. And up until two years ago, this machine was pulling shots. Then the former owner came here and never changed the plug.

So, I'm ready to try out this splendid machine but am inexperienced with changing power cords on appliances and thought I'd ask for help to do this right.

The cord exits the machine, goes to an on/off inline switch and then into the converter box. The box has a dial that must be a rheostat, and then it connects to a 220v European plug. I'm happy to keep the on/off switch and am happy to lose the rheostat. I assume all I need to do is figure out which leads go to what parts of a U.S. plug, and we'll be up and running.

Here's a picture of that setup with the project box opened:



And here's how the connections look inside the box with the line to the machine coming in from the left:



Here's another angle with the line from the machine coming in from the right:



So forgive my completely ignorant beginner's questions while I figure out how to attach a three-pronged plug. It looks to me like the yellow-green cord that goes all the way to the other side of the box is the ground that would connect with the round prong of a three-pronged plug and the other two (dull orange and blue/grey leads) that connect to the first two screws on the bottom left connect with the flat prongs. Is that right? And does it matter which non-grounding lead goes to which flat prong? Since it's alternating current, I assume the poles alternate, so that shouldn't matter, but what do I know? (Hey! We all have to start somewhere!)

Guide me to the light, please?!

See http://en.wikipedia.org/wiki/Consumer_m ... conductors

It definitely matters which line is which.

On US cords, black is line, white is neutral and green is ground

Thanks, Ian. That's why I asked!

I found a tutorial on changing three prong plugs that also said it matters which flat blade is which here: http://www.hammerzone.com/archives/elec ... eplace.htm , and I don't want to change what could be a lovely espresso experience into a shocker and burned components ...

So to translate the Wikipedia technical article about European wiring I've got into the U.S. standard and bring it together with the tutorial on connecting a three-pronged plug, are these the equivalents?

Blue/grey is line = U.S. black, which goes on a gold terminal?

Brown is neutral = U.S. white, which goes on a silver terminal?

Yellow/green is ground/earthing = U.S. green, which goes on a green terminal?

If it helps to understand what I've got, here's how the connections go into the bottom of the machine, that is stamped to indicate it's made for 110v.

Your wire mapping is correct according to the color codes.

What is the the 'knob / button / ????' on the lower right front of the machine?

Normally one would interrupt Line, not Neutral. If the 'black box' is a pressure stat, it's breaking the neutral, IF the box wiring is not flipped.

Is the wire that comes off the left of the 'black box' [pressure stat ?] bare?
IF so, that's probably why the neutral is broken.

You can test the 'safety' of the wiring by connecting between Gnd + Line and Gnd + Neutral with an ohm meter.
The reading should be infinite.

Thanks, Ian, for confirming the color codes.

The device on the bottom right front of the machine is a spring-loaded switch. If you press down on it, it touches a contact in the black box in the base. It has the solid feel of a telegraph key. That black box has a set screw that adjusts for temperature, so my best guess without operating the machine yet is that if you hold down the switch, it's a way to turn on the element continuously to come up to full steaming power, maybe like a more modern machine where we activate a steam switch to boost temperature. In this case the spring action would prevent it from being left on and risk boiling out the machine. I think the manometer hidden behind the grouphead would indicate whether steam pressure has built up. It tops out at 3 millibars.

Is the black box inside the base a pressurestat or does it regulate heat or both? Not sure.

The wiring inside the base looks like all the connections are good and intact. The power cord itself appears to be heavy duty and in perfect condition. Since the prior owner said it functioned just fine and it is designed for 110v, I'm thinking of changing the plug, filling the boiler and trying it out while being alert to any sign or smell of overheating, which I don't expect. If I saw any sign of faulty connections, bends or cuts in the power cord or burnt contacts, I would check with a multimeter, but I think all the wiring's intact.

Dr.G: If the machine is originally 120 volt (nameplate?) then the box with the pot on it has to be removed or fully bypassed. It looks like a solid state voltage converter and the pot (potentiometer) must be to trim the voltage (adjust to actual conditions). If the machine is 120v just remove the box and attach a US plug on the cord, using the information you already have, exiting the machine, then if you need more length use a 12 or 14 gauge extension cord.
Duke Masters, retired electrician

Hi Duke,

Yes, it's 110v and that's what I'm going to try and do, remove the box entirely that converts to 220v but keep the on/off switch that's on the cord and simply attach a plug. I'll keep you all posted. If you don't hear anything and there's a report of a small explosion on El Camino in Mountain View, CA, then you know what happened! BTW, I'm still searching Craigslist for the vintage machine you see in my avatar. Anyone seen one of those on eBay?

Gary: It looks like that switch was original equipment but you might want to check it's amp capacity. I've read a description of your avatar machine in, I think, a Tolstoy novel.
Duke

Duke,

Here's a picture of the box, closer up. I think it reads 15 amp.



So I just got back from the hardware store where I got the heaviest duty plug they sell, which is rated for 15 amps.



And then to play it extra safe (probably unnecessarily) for this test run, I also picked up a portable GFCI plug rated at 15 amps. That'll be good to have around anyway if we're using power tools in the yard.



Short of calling the power company and asking if they would shut things down if they measure the slightest dip in capacity, I think I'll be set to go!

How about removing that box, and just using a plug converter from Radio Shack?