UMC Wiring

[samcarney]

I opened up my 14-50 adaptor end. (gotta love the 8MP cellphone camera)

View attachment 2477
View attachment 2478

It appears that the maroon/purple wires are connecting the green wire to the white. (does the maroon connect to the white? It is hidden in the photo) (could there be a diode or other device between the maroon and white wires?)
If there is nothing but another wire connecting the green and white wires then it does not work the same as an RFMC. If the RFMC senses a short circuit between green (ground) and white (pilot signal) it shuts down.

 

[W.Petefish]

The maroon (purple actually) wire only connects to the ground on the california connector.

You can see the dead end of the wire on the 14-50 plug end if you zoom in.

 

[jaanton]

You will need to take apart something other than the 14-50 connector. I'll bet that grounding the neutral on that connector means full 40 amps.
In the U.S. the only amp levels the UMC will produce are 40, 24, 16, and 12. That could be done with a simple diode scheme. It would make sense that the 14-50, the most common connector, is also the simplest. I have a 6-20 connector for the UMC, I've done some simple signal tests and I'm certain there is a diode in there.

 

[suxxer]

Yep... But does the UMC work in the same/similar way to the RFMC?

Why shouldn't it? Martin could be the father of both of them.

You could measure the pins of the connectors to find out if there are any diodes involved. Fast & easy way to tell....

 

[dpeilow]

I was told that the official line on the RFMC was that it was felt to be dangerous. That could be sour grapes of course but it wouldn't suggest that ME was the father of both.

 

[S-2000 Roadster]

I was told that the official line on the RFMC was that it was felt to be dangerous. That could be sour grapes of course but it wouldn't suggest that ME was the father of both.

Who's to say that the official line did not originate with M.E.? He could have discovered any dangerous tendencies in hindsight and redesigned the UMC to correct them. So far, I get no clear evidence one way or the other, because either possibility seems plausible.

 

[suxxer]

I remember TM had problems with the "new" UMC when introduced to Europe. They said it had something to do with the bi-metal stripe inside the connector. The UMC would shout down if the connector got too hot in sunny areas. That might be evidence, that the UMC-Design can't be too far away from M.E.'s (since he's using bi-metal inside the connector as high temperature shut down too)

 

[donauker]

I was told that the official line on the RFMC was that it was felt to be dangerous. That could be sour grapes of course but it wouldn't suggest that ME was the father of both.

The RFMC does not have a GFI or contactor so the connector pins are hot whenever it is plugged in.

 

[doug]

Who's to say that the official line did not originate with M.E.? He could have discovered any dangerous tendencies in hindsight and redesigned the UMC to correct them.

Highly doubtful.

 

[vfx]

... M.E.? He could have discovered any dangerous tendencies in hindsight and redesigned the UMC to correct them....

Martin was fixing RFMCs that he did not even make. He personally knows many of the owners of the dozen or so he crafted himself so I would be shocked (!) if he left them hanging with less than a perfect product.

 

[SByer]

The RFMC does not have a GFI or contactor so the connector pins are hot whenever it is plugged in.

Yeah, I've always sort of assumed this, so I typically disconnect the RFMC at the CA connector and hang that up on the wall. Also eliminates a little bit of vampire power draw. The CA connector seems to be built to take a lot of connect/disconnect cycles (so I also just leave the 10-30 side plugged in to the wall, since it's clearly not meant to take it).

 

[dpeilow]

Who's to say that the official line did not originate with M.E.? He could have discovered any dangerous tendencies in hindsight and redesigned the UMC to correct them. So far, I get no clear evidence one way or the other, because either possibility seems plausible.

Because he'd left the company before either product came out.

 

[TEG]

I recall that there was heavy demand for something like the RFMC / UMC as people were finding that the MC240 just wasn't optimal/flexible for a lot of possible charging situations. When the RFMC came out, people were excited and wanted them, but it wasn't long before the UMC came out and somewhat obsoleted the RFMC.
Perhaps the early RFMC availability forced TM to get the UMC out sooner rather than later. I don't know if the two products were independent efforts or share some similar DNA.

I am hesitant to say that the UMC obsoleted the RFMC, but it did have some benefits including:
* Direct from the car company, not a 3rd party.
* Smaller, more integrated looking design.
Are there technical details of UMC that make it a better choice than RFMC, or is it primarily aesthetics, availability, and "factory approved?"

 

[mpt]

Great timing; I sat down yesterday and thought, I wonder if I can make my own UMC heads? Problem is the twist lock connector that TM uses has been adapted with the metal ring. The UMC side has a metal clip protruding in in such a way to prevent standard twist lock connectors from Home Depot from being inserted without first being heavily modified physically. And that's before any electrical alterations to signal the current. Cunning stunt eh?

 

[suxxer]

Ok - let's stop guessing around and measure out those adapters.

We have four possible connection points iside the california twist lock connector: red ring, black ring, green ring, white ring (see pics...).

I have two of them: one 10A and one 32A adapter. (I have a SWISS Version of the UMC, so default is 10A).

The 10A adapter:
It is build according to M.E.'s 15A schematic (http://www.teslamotorsclub.com/attachment.php?attachmentid=2481&d=1314961464). Look at the following image:
Only phase (red ring, brown cable), neutral (black ring, blue cable) and ground (green ring, yellow-green cable) are connected. The third pin (white ring) is empty. The purple pilot cable is missing too.
I guess the umc defaults to 10A if the purple pilot cable is left open.

The 32A adapter:
Phase and neutral (black and red cable) are on red ring / black ring and ground is on green ring with a green-white cable. We have the purple pilot cable shorted together with the ground wire on the white ring. This adapter is not built according to M.E.'s RFMC specs.

Furthermore the purple wire is left open on the CEE32-Connector side. So it's just a shortage between ground and white ring.

The 32A is the "biggest" adapter for the SWISS UMC. If we look at the images from W.Petefish (http://www.teslamotorsclub.com/attachment.php?attachmentid=2478&d=1314941461) we can see that his 50A adapter (which is the "biggest" adaptor for US UMC's) has the same wiring: purple is shorted together with ground.

So those two cases are very clear now: the "smallest" adapter has an open purple pilot wire while the biggest adapter has the purple pilot wire shorted together with the ground wire.

I don't have other adapters at hand. Could anyone else measure out the remaining adapters(30A for US UMC's)?

 

[doug]

I recall that there was heavy demand for something like the RFMC / UMC as people were finding that the MC240 just wasn't optimal/flexible for a lot of possible charging situations. When the RFMC came out, people were excited and wanted them, but it wasn't long before the UMC came out and somewhat obsoleted the RFMC.
Perhaps the early RFMC availability forced TM to get the UMC out sooner rather than later. I don't know if the two products were independent efforts or share some similar DNA.

As an additional historical note, something like the RFMC/UMC is what was originally promised as the travel connector that was to come with the Roadster. By the end of the Sig100 series only the MC120 (now called the "Spare Connector") was available. Regulatory hurdles seemed to delay Tesla being able to offer even the MC240 for quite a while. Martin had been forced from the company since before even the first production Roadster had been shipped.

 

[W.Petefish]

Great timing; I sat down yesterday and though, I wonder if I can make my own UMC heads? Problem is the twist lock connector that TM uses has been adapted with the metal ring. The UMC side has a metal clip protruding in in such a way to prevent standard twist lock connectors from Home Depot from being inserted without first being heavily modified physically. And that's before any electrical alterations to signal the current. Cunning stunt eh?

As stated in a previous post, the twist lock connector is a standard california connector available from any electrical supply house.

Anyone have a 30A US UMC end that they would be willing to pull apart and look into?

 

[TEG]

As an additional historical note, something like the RFMC/UMC is what was originally promised as the travel connector that was to come with the Roadster. By the end of the Sig100 series only the MC120 (now called the "Spare Connector") was available. Regulatory hurdles seemed to delay Tesla being able to offer even the MC240 for quite a while. Martin had been forced from the company since before even the first production Roadster had been shipped.

Yeah, I think Martin mentioned doing the RFMC on his own separately from the group that did the UMC. So they had a similar goal, but different engineering.
Perhaps he was glad that the UMC came out so he didn't have to keep fielding requests for more RFMC support.

 

[jaanton]

Putting a meter onto my NEMA 6-20 adaptor shows a diode, small signal silicon, cathode connected to ground and anode connected to what would be the neutral.
Hope Tesla doesn't mind a little reverse engineering.

 

[W.Petefish]

Can you open it to confirm?