Trying To Understand Single vs Triple Phase

[jyl]

I have an appliance (espresso machine, not the same one that I've previously posted about). It has five wires in the cable: black, black, brown, blue, green/yellow.

It came with a 240v 30A twist lock, 3 prong plug and was wired as follows :
- green/yellow wire to ground prong
- blue wire to a hot prong
- both black wires and brown wire together to other hot prong

The manual for this machine says
- green/yellow is ground
- blue is neutral
- black, black, brown are the three phases

The manual also says the machine can be connected to 240v single phase power "without modification". "hook up the ground and neutral wires to the two respective terminals on the electric switchboard. Join up the three wires of phases 1, 2, 3 together and connect them to the single terminal of the phase present in the electric switchboard". It also says a plug may be used.

I have to replace the existing plug with a 240v 50A 3 prong plug. 6-50R type.

I think I connect the new plug as follows:
- green/yellow to ground prong
- blue wire to a hot prong
- black, black, brown wires together to other hot prong

Basically I'm copying how the existing plug is wired and it sounds consistent with the manual.

What I'm trying to understand is why does this work. Why is the machine okay with all three phases being wired together? How does it "know" if it is wired to 240v single phase or to 400v triple phase?

[Hugh R]

JYL, you are a math guru and I think otherwise Illuminary, walk away...

[jyl]

Well, I plugged it in and turned it on, used a VOM to check for voltage where there shouldn't be any, everything is fine. Machine works! Couple issues: hot water valve leaks when actuated, left group flows less than right group, brew pressure gauge reads 3 bar when not brewing (guessing gauge just failing to return to zero), and need to verify that autofill works. But otherwise seems okay. Haven't tried pulling any shots yet.

This is a 2000 Elektra commercial 2 group that I bought off CL for $200. Have $50 into it. Going to get it working - not a spit and polish restore, just working - and sell it to a friend who is a small commercial coffee roaster and is looking to start a cafe. I'll sell it to him for what I have in it, hopefully less than $500 when done. In return I hope to get an education in roasting.

[jyl]

[red-beard]

Originally Posted by jyl

I have an appliance (espresso machine, not the same one that I've previously posted about). It has five wires in the cable: black, black, brown, blue, green/yellow.

It came with a 240v 30A twist lock, 3 prong plug and was wired as follows :
- green/yellow wire to ground prong
- blue wire to a hot prong
- both black wires and brown wire together to other hot prong

The manual for this machine says
- green/yellow is ground
- blue is neutral
- black, black, brown are the three phases

The manual also says the machine can be connected to 240v single phase power "without modification". "hook up the ground and neutral wires to the two respective terminals on the electric switchboard. Join up the three wires of phases 1, 2, 3 together and connect them to the single terminal of the phase present in the electric switchboard". It also says a plug may be used.

I have to replace the existing plug with a 240v 50A 3 prong plug. 6-50R type.

I think I connect the new plug as follows:
- green/yellow to ground prong
- blue wire to a hot prong
- black, black, brown wires together to other hot prong

Basically I'm copying how the existing plug is wired and it sounds consistent with the manual.

What I'm trying to understand is why does this work. Why is the machine okay with all three phases being wired together? How does it "know" if it is wired to 240v single phase or to 400v triple phase?

First, 3 phase power can be done multiple ways, so it is not a one size fits all.

If the machine as setup is the black & brown are tied together on a single 240 and the Blue is neutral, that is NOT USA type wiring. That sounds European style 230, single phase.

Can it work with the blue connected to one hot, and the rest tied together on the other hot? Maybe. That is single phase 240VAC. The Neutral in the US wiring is for 120VAC from a hot.

As far as "three phase" wiring, USA "Delta" 480VAC circuits are 277 to neutral, so that will not work. The other is 120/208 Volt "Wye". But the 208 is phase to phase.

230/400VAC is not standard in the US.

https://ctlsys.com/support/electrical_service_types_and_voltages/

[biosurfer1]

Originally Posted by afterburn 549

This is not sarcastic- how can Euro electricity be different than American?
I do know they use a different AC number, but.........

The electricity isn't different, the wiring is.

[Zeke]

Originally Posted by afterburn 549

Got that!
But if it the same...how can it be different? (the wiring)

The way it is generated and transformed. Not all electricity is created equal.

[LWJ]

Euro electricity oscillates at a different frequency 50Hz vs US 60Hz. Also, European voltage is 220 vs our 120.

Electric Differences in Europe. 220 volts and 50 Hz.

[legion]

Would it be a good idea to use a phase converter to run this?

[red-beard]

My concern is the pump. Pumps are usually designed for a specific frequency.

[Zeke]

Originally Posted by legion

Would it be a good idea to use a phase converter to run this?

why? I thought he said it was working. All this talk about wiring it single phase vs. 3-phase is academic.

[carambola]

i don't trust you to follow directions

Get a phase converter and we will talk

[PD41]

Think of 240 single phase as double pole or 2 phase.
The advantage of 3 phase is is it uses less current or amps which saves money in the long run.
If you have 3 phase panel you could pull a 3rd hot wire and a 3 pole / 3 phase circuit breaker and wire it for 3 phase.

Many machines and transformer's are designed to work with various wiring configurations.

[Zeke]

Originally Posted by PD41

Think of 240 single phase as double pole or 2 phase.
The advantage of 3 phase is is it uses less current or amps which saves money in the long run.
If you have 3 phase panel you could pull a 3rd hot wire and a 3 pole / 3 phase circuit breaker and wire it for 3 phase.

Many machines and transformer's are designed to work with various wiring configurations.

That's how North American works. Euro is the same as our 120v but the hot leg is 230v, not 240v shown across two legs of 120v. Their 230v requires a neutral whereas technically ours doesn't.

[jyl]

MBATarga's explanation about the heating element not caring about phase makes sense. Caramobola's concern about the pump motor also makes sense. However, the machine is running fine, it's been "on" and pulling shots etc in my garage for 48 hrs. I just unplugged it to track down a flow issue with the left group. It is an Italian made machine but was here in the US.

[jyl]

[jyl]

The friend I'm selling it to is a retired building code inspector. I figure he must know electricians, or maybe is one himself, so he can do whatever is necessary when he installs it in his place. I'll advise him of the electrical question/issue when he comes to get the machine. His shop has a big commercial coffee roaster so he must have 240v.

I'll be a little sad to see this machine go. It is newer and in some ways nicer than the Elektra I'm keeping for myself!