Electrical advice needed from electrical Gurus

[Lil Foot]

I have a solid state phase converter that gives me 208v 3 phase that supplies my mill & a grinder.
I would like to wire the grinder with a single 60w, 110v outlet for a work lamp. Seems we did this lots of times (30years ago) in the shop at work, but I can't for the life of me remember how we did it.

The power cord to the grinder is 4 wire; red, blk, wht, grn.
The wires from the grinder are marked L1, L2, L3.
L1 is connected to blk.
L2 is connected to red.
L3 is connected to wht.
Grn is connected machine frame.
Any practical way to pull my 110v from from this wiring?

I don't want that essential smoke that keeps all things electrical running to escape, thereby disabling my equipment.
Thanks.

 

[Daren Todd]

Should be black white and ground. But you will have to meter the wires to be sure. Usually for 220, black and red are each a 110 volt power, white is neutral, green or bare copper is ground.

But I'm not an expert. So I break out my multimeter and verify

 

[anthonyv]

maybe this will help

 

[North Idaho Wolfman]

Yes just like anthonyv picture.
Any single hot leg to neutral will give you 120V.

 

[ArticiferTom]

You are not showing a neutral so you either need a step down transformer or 220v lamp bulb if they still make them . Some grinders have a tap off leg build in for the light , that is why they do not come on until started .

 

[Lil Foot]

Which highlights my dilemma: I appear to have 3 hot legs (L1, L2, L3) and a GROUND, not 3 hot legs & a NEUTRAL.
Unless you're saying the frame ground can be used as a neutral?
Doesn't seem safe- if something fails. Under a failure mode, wouldn't the machine frame become hot & I then become the ground path?

 

[BruceP]

With your current setup, there is no SAFE way to get 110v.

I guess you COULD find an isolation transformer which converts 3-phase (or two legs) to 110v.... but that may be expensive and still unsafe under some situations. (Transformers of that capacity are heavy, large and costly)

If you own a 3-phase welder that has a 110v convenience outlet, you could use that as a way to get 110v. (Welders are simply large transformers)

The PROPER way to do what you want is to install new power chord with 5 conductors so you also have a neutral wired back to the panel.

 

[Lil Foot]

With your current setup, there is no SAFE way to get 110v.
I guess you COULD find an isolation transformer which converts 3-phase (or two legs) to 110v.... but that may be expensive and still unsafe under some situations. (Transformers of that capacity are heavy, large and costly)
If you own a 3-phase welder that has a 110v convenience outlet, you could use that as a way to get 110v. (Welders are simply large transformers)
The PROPER way to do what you want is to install new power chord with 5 conductors so you also have a neutral wired back to the panel.

That's what I was afraid of.
That would require a new cord setup on the grinder, it's extension cord, the cord from the converter to the mill, and then back to the panel.
Guess I'll be stringing a 110v extension cord when I need light.

Thanks everyone.

 

[85Hokie]

I have a solid state phase converter that gives me 208v 3 phase that supplies my mill & a grinder.
I would like to wire the grinder with a single 60w, 110v outlet for a work lamp. Seems we did this lots of times (30years ago) in the shop at work, but I can't for the life of me remember how we did it.

The power cord to the grinder is 4 wire; red, blk, wht, grn.
The wires from the grinder are marked L1, L2, L3.
L1 is connected to blk.
L2 is connected to red.
L3 is connected to wht.
Grn is connected machine frame.
Any practical way to pull my 110v from from this wiring?

I don't want that essential smoke that keeps all things electrical running to escape, thereby disabling my equipment.
Thanks.

IF all three are carrying current - AND you have NO neutral, you cannot pull 110v from that ( you cannot (should not) use the ground as a neutral)

IS the white wire neutral or carrying current? IF neutral then you are golden, if the white is carrying current - you cannot do this safely.

https://kb.samsara.com/hc/en-us/articles/217224107-Three-Phase-Power-Configurations

 

[Lil Foot]

IF all three are carrying current - AND you have NO neutral, you cannot pull 110v from that ( you cannot (should not) use the ground as a neutral)
IS the white wire neutral or carrying current? IF neutral then you are golden, if the white is carrying current - you cannot do this safely.

I will check tomorrow, but I think all 3 are carrying current, otherwise I'd have another wire. (the illusive neutral)
As I undertand this, to pull off 120v, I would have to have the "wye" setup illustrated in the first schematic on the page you posted.
What I have (apparently) is the "delta" setup shown in the second schematic on the page you posted.

Thanks for posting this, it clarifies things immensely. I've added a bookmark for this page to my machining folder.

 

[anthonyv]

In rereading this post i am guessing that you do not have a true 3 phase service into the shop, but an electronic device to convert existing single phase 220 to mimic 3 phase for the grinder. In this case I would not do anything to disrupt the converter without some knowledge it could handle a single outlet & not disrupt the other hot leads, current & avoid possible damage. Also if that is a ground or neutral lead. If you have 3 phase from the street this would not be a problem. Also keep in mind the drawing I sent earlier I failed to mention that when using 3 phase as a 208v(220) in most cases motors that are not 3 phase & some equipment, will need to be rewired for low voltage since 3 phase is only 208v. 220v Motors will burn up if not rewired or tapped for lower voltage. Trying not to turn this into a lengthy discussion, hope this helps.

 

[Lil Foot]

i am guessing that you do not have a true 3 phase service into the shop, but an electronic device to convert existing single phase 220 to mimic 3 phase

Correct. This powers both the mill and the grinder.

Also if that is a ground or neutral lead.

The 4th lead (grn) is a ground, no neutral, all three other wires are hot.

will need to be rewired for low voltage since 3 phase is only 208v

Both are 208v 3 phase motors.

Thanks again. Hopefully this thread will help someone else as much as it has helped me.

 

[bxray]

Usually those devices are 3ph delta.
In that case if tou try to pull 120v you will burn things up.
Did that once!

Usually a 3ph wye has 5 wires
Black, red, blue, white and green.
They are using a cord and should have marked the white with blue band/tape.

Use a stepdown transformer.

Here is a 100w one.
You can use an led lamp that requires a lot less wattage.

https://www.110220volts.com/100-watt.html


https://www.110220volts.com/7-ss200w.html


Ray

 

[twomany]

If your shop has only single phase service (You indicated so)

Then the three "power wires", L1 L2 and L3 offers possibility, for only two of them are required to deliver single phase 208 -240 Volt to a VFD etc.

I'm thinking the "white wire" that you see may be "repurposed" to provide a NEUTRAL back to the service panel. This neutral, combined with another 110V power line, may provide the 110 lamp service you desire.

Look at the PANEL! Where are those wires connected? Are any NOT connected? Could there be an arraingment that delivers 220V to the phase converter and also provide a neutral wire attached to the neutral bus?

I bet there is a way!

 

[Yooper]

Not to beat this to death, but when you say solid state phase converter, is it a static converter or a VFD? If its a VFD, some of them have a built in transformer for 24v DC that may or may not be capable of a LED light. One thing for certain is you do not want to grind without a good light.

 

[anthonyv]

We can beat this theory to death, but until one is certain of what device is being used, my recommendation is to leave it alone. Lil Foot just run a wire from a 110 source in the work shop to a light & don't take a chance of burning something up & having to start over. Not worth the cost & aggravation.

 

[BruceP]

That's what I was afraid of.
That would require a new cord setup on the grinder, it's extension cord, the cord from the converter to the mill, and then back to the panel.
Guess I'll be stringing a 110v extension cord when I need light.

Thanks everyone.

WAIT!!! All you are looking for is LIGHT??? (I guess I missed that in your initial question)

I am pretty sure you could find some kind of lighting system that works off a couple of those 208 legs. (and the ground fir safety)

For example, if you read the allowable input voltage on florescent ballasts.... some of them are rated (120/208/240/277) They are very forgiving what voltage you feed them. A quick Google search of "florescent ballast" will reveal this. (I beleive the GE ProLine includes 208v input ratings)

 

[ArticiferTom]

Some new LED light work on voltage ranges with out taps . So can be hooked on any voltage between it range .

 

[Tunaslayer]

If you have single phase 120/240 in the building, run a circuit from the main panel, or the closest 120v outlet, and feed a lighting circuit that way. Where you are using a solid state phase converter, I would stay away from it. Those are big bucks now, and repairing them is a drag. I have seen, and repaired the guts on those, and it is not fun.


Sent from my iPhone using Tapatalk

 

[Lil Foot]

Here is the converter I'm using, and I will just use a separate 120v 3 wire cord for my work light.
http://www.phase-a-matic.com/StaticInstallation.htm