I read a number of the other posts and don't disagree with any of them.
But since your neighbors get the dimming, too, I'd go to the utility
company right away. You are going to have to do that sooner or later
anyhow.
We live out in the country where we have our own transformer on the
pole.
Some years ago we replaced an old farmhouse with a new house and
installed a 200 amp breaker box with "400 amp" leads to the pole. Three
years later on a hot summer day, we were holding a power hammer
rebuilding workshop and the power went out. I called the utility co.
and they came out right away. Reset the breaker on the pole and told me
"gee, you sure are pulling a lot of power. You are drawing 54 amps on
one leg and 57 amps on the other!" (To which I said "Sure sounds like I
have 'em well balanced.")
I told 'em that 55 amps shouldn't be a problem since I have a 200
amp service that is almost new that they recently hooked up to.
----Now, HERE comes the point:
They said --- 'yeh, but we never install transformers big enough to
handle the max load from your main box. We always assume that you only
got that big box so you'd have a lot of extra breakers!!!"
So, if your utility co. used that reasoning and if they did it 20
or 30 or 40 years ago, it's quite likely that the whole neighborhood is
underpowered.

By the way, they removed my old 5 or 7.5 KVA transformer and installed a
10 or 15 KVA and no troubles since.

Pete Stanaitis

wrote:
I recently bought a milling machine with a 3hp motor. I purchased a
7.5 hp rotary phase converter and hooked it up to my mill. I have a
100 amp 220 service to my house. Unfortunity I have noticed that when
I first turn the mill on the lights in my shop quickly dim due to
starting of the mill which I understand. My problem is my electric
line is shared with my neighbor then goes to the transformer on the
pole. Another neighbor is also hooked up to the same transformer and
everytime I start the mill the neighbors lights also dim quickly...My
question is due you think I should get the power company to fix the
problem? Do I really need to get a bigger service (200amp) even
though I am only running one machine?

Thanks