Some help with some odd motor wiring

[King Seven]

I will post a picture tomorrow if need be, but I suspect a few people here probably know the answer to this.

Slightly confused by the wiring to a motor on my old Gothot sample roaster. It has 4 wires - Blue, Brown, Yellow/Green and Black. Does this mean it is 2 phase? (sorry if that is a stupid question....)

Any idea what is going on here? I can post pics of the plate on the motor with the details and the wiring itself tomorrow to maybe explain better....

[HB]

I'm not an electrician, but from what I've read, the answer depends on the year of manufacture. See US and Europe wiring standards what color is which wire? and wikipedia's Electrical wiring (UK).

[Psyd]

Slightly confused by the wiring to a motor on my old Gothot sample roaster. It has 4 wires - Blue, Brown, Yellow/Green and Black. Does this mean it is 2 phase? (sorry if that is a stupid question....)

Not a stupid question, as you Brits have done some slight changes recently. Quite often, the same cable is used for quite a few different applications (My eighties La Pav Pub still has an Italian Standard 220V cable on it, but is wired for 110V) and may contain a wire that isn't connected at either end. While I'm not entirely familiar with British wiring standards, I am passable at them, and fairly familiar with industrial standards. Ish...
That said, there is very little that is designed to run on two phases. *Usually* stuff gets designed to run on a single phase, or on three phases. I've run into lots of each, and never discovered anything that will run on two. It's still possible. The best way to do it is to follow the leads back to see where they go (and pics won't hurt) and find out what they're doing. This will tell you how they want to be wired. My LP has a wire living in the sheath that does nothing, and I just consider it a ready spare.
Green with Yellow is going to be ground, Blue is (probably, when was this thing last connected to power, and where was it?) Neutral, and Brown is Live. Black is usually used for a Live line, but if it were three-phase, there would be a grey in there somewhere. Post some pics of the other end, and we'll be able to decide whether you're going to electrocute yourself or set the thing on fire. Or maybe, just maybe, get it right!

[King Seven]

Some pictures:





Any thoughts? (apart from it needing a damn good clean)

[paslug]

It is probably a 3 phase motor, wired for 220 volts

Your blue, brown, and black would be the 3 phase wires. Yellow/green would be the ground

Groschopp is a pretty good company, & probably will be able to help you out

their website is groschopp.com

contact info:

Groschopp, Inc. ·

420 15th Street NE Sioux Center · IA 51250-2100
(712) 722-4135 · Toll Free: (800) 829-4135 · brendab@groschopp.com

[AndyS]

It is probably a 3 phase motor, wired for 220 volts

Your blue, brown, and black would be the 3 phase wires. Yellow/green would be the ground

I'm with paslug, it's gotta be a 3 phase motor. That's what the little Y and Delta symbols on the left side of the nameplate are telling you (this is different from the States, where there'd usually be a "Phase" space that said "3").

[King Seven]

Ok - consensus says it's three phase - but how do I wire it in?

Spent all day scrubbing crap off the insides of it, amazingly dirty. Then repainting the front of the barrels with high temp paint. Hours of fun!

Underneath one of the barrels:

[ira]

Ok - consensus says it's three phase - but how do I wire it in?

Well, if you don't have 3 phase you either start it with a capacitor and run it single phase or buy a new motor. Single phase works if you're running it well under capacity, but if the machine needs all the power the motor produces you'll need 3 phase or a new motor. In the US at least houses don't have 3 phase unless they accidentally bring all 3 in because you have 2 breaker panels.

Ira

[paslug]

Ok - consensus says it's three phase - but how do I wire it in?

Can we assume that there is wiring in the roaster for it? If so, you will connect the 3 power wires to the blue, brown, & Black wire terminals, & the ground wire to ground.

More importantly:

Are you running this in your home?

Does London have 3 phase power to residential? Here in the states it is very unusual.

Is the roaster gas fired? If electric, you may find that the heat elements are wired for 3 phase

Are there any other motors on the unit?

Or is your question "how do I hook up a 3 phase unit to single phase?"

[paslug]

Another thought,

If this is the only 3 phase load on the roaster, you could run it with an inverter drive. You can feed single phase into the drive, & get 3 phase out, and run the motor at full load.

Here is a link to an ebay ad for one.

ALLEN BRADLEY 161 SERIES SINGLE PHASE INVERTER DRIVE

This looks like a very low horsepower motor, & should run with a 1/2hp inverter with no problem.

The inverter takes a little bit of configuration to set it up, but it's not brain surgery. just download the manual for it & study it a little.

[King Seven]

The roastery has three phase power. I guess it should be easy enough to install (if I pay someone to do it - my lack of electrical knowledge coupled with a healthy fear of death necessitate this), just unsure if there were anything weird about it not having the fifth wire I'd expect on a three phase machine.

[Paul_Pratt]

The roastery has three phase power. I guess it should be easy enough to install (if I pay someone to do it - my lack of electrical knowledge coupled with a healthy fear of death necessitate this), just unsure if there were anything weird about it not having the fifth wire I'd expect on a three phase machine.

James there is no neutral, the wiring configuration essentialy creates a neutral point, my Probat is the same. It's slightly different than a typical espresso machine that is 2PH (4 wire) or 3PH (5 wire) as the elements require a neutral. It's always good to get a pro check things out. The only thing you need to watch out for is the motor rotation, changing any 2 wire reverses the direction.


Paul

[AndyS]

The roastery has three phase power. I guess it should be easy enough to install (if I pay someone to do it - my lack of electrical knowledge coupled with a healthy fear of death necessitate this), just unsure if there were anything weird about it not having the fifth wire I'd expect on a three phase machine.

Definitely sounds like the time to call in an electrician. A healthy fear of death can be very healthy sometimes.

BTW, I don't know how things work in the UK, but it is rare for a 3 phase machine in the States to have five wires; they're all just three hots plus a ground.

[ira]

BTW, I don't know how things work in the UK, but it is rare for a 3 phase machine in the States to have five wires; they're all just three hots plus a ground.

That's three phase delta, three phase Y has 5 wires. Don't know how common it is, but if you expect to get 110 legs off of 240 3 phase you need 5 wires.

Ira

[AndyS]

That's three phase delta, three phase Y has 5 wires. Don't know how common it is, but if you expect to get 110 legs off of 240 3 phase you need 5 wires.

I don't know how common it is, either. Around here (Western NY) any 3 phase machine that needs 115v for control circuitry has a small transformer in the cabinet that knocks the 208v down to 115v.

[ira]

But if you've got three phase coming into a commercial building it's not uncommon to get 110 by going between the center and ends of the Y, at least I've done that before when there was only 3 phase to work with. Even if things are wired delta, somewhere the center of the Y is always there and connected to ground so that ground is always a reference.

Ira

[AndyS]

But if you've got three phase coming into a commercial building it's not uncommon to get 110 by going between the center and ends of the Y, at least I've done that before when there was only 3 phase to work with. Even if things are wired delta, somewhere the center of the Y is always there and connected to ground so that ground is always a reference.

That's true. For instance, my building has a 1000 amp 480 volt 3 phase service. The voltage between any two phases is 480, used for larger three phase motors. The voltage between any phase and neutral is 277, used for lighting circuits (one can use smaller gauge wire at 277 volts than at 110 volts).

There are also several large transformers that reduce the 480 volt three phase to 208 volt three phase. This is used for smaller motors. Between any of the 208 volt phases and neutral is 115v, which is used for all the household-type stuff.

[Psyd]

But if you've got three phase coming into a commercial building it's not uncommon to get 110 by going between the center and ends of the Y, Even if things are wired delta, somewhere the center of the Y is always there and connected to ground so that ground is always a reference.

Ehm, Delta and Wye are two separate wirings, and if you have the center tap, it is a Wye setup, and things aren't going to be wired Delta, and the center of the Y isn't always there. It's why that's called a Delta setup.
Then there's the 'Wild Leg' in some setups, used to wire a motor startup, and some other esoteric apps., with the addition of it being in a country that does things quite a bit differently from us in a lot of ways (like, f'rinstance, ring circuits and earths at stations as opposed to locally) plus the ever-present threat of death, or worse, letting the magic blue smoke outta your new toy, and you prolly want to get an electrician in. The good news is that I have a buddy in Glasgow that'll do it for coffee and a round trip ticket to London, and it's probably just (with hotel and per diem) slightly cheaper than hiring one in local! ; >