Re: [CAD_CAM_EDM_DRO] 3 phase motor math

Abby

I don't know how things are in the UK, but I have a 15
HP 3phase that I am building into a rotary convertor.
This will replace the static convertor on my lathe and
be available to the whole shop. Anyway, I took it over
to the motorrepair shop and asked them to check it out
and let me know how it was hooked up (y or delta). I
explained what I was going to use it for and told them that
I wasn't in a hurry for it. I probably take one motor a year
to them to repair. It took several weeks before they had
a chance to get it to the bench and check it out. It was
delta connected for 220, just what I wanted.
THEY DIDN'T CHARGE ME FOR CHECKING IT OUT.
I left $10 to buy soft drinks for the shop. They didn't
do anything except check the wiring and hooked it up to check it
out. They would have given me an estimate, if in fact there was \
something wrong before they started work on it.

bob mcknight
phoenix, Arizona USA





In a message dated 5/16/2004 2:49:21 PM Eastern Daylight Time,
cnc@... writes:
Hi guys,

I have a nice old 3 phase motor I want to hook up to my VFD. I've gone
through all the motions of opening it up and cleaning it a bit, and
checking the resistace between windings and ground, and it seems
okay.
What I don't know however is whether it's wired right..

My VFD outputs 220V, so I'd need the motor to be in the Delta
configuration.
The motor has the following written on it:

Volts: 220/380-415
Amps: 3.45 / 2.0

I measured 25ohms between each connection point...
But the usual V=IR formulas totally don't yield me any answer.. it
must be because it's 3 phase and AC.

I Googled for 3 phase motor/resistance/amps formulas but only came
up
with a lot of junk people were trying to sell me, and some other
stuff. How do I work out what voltage this motor is currently
configured for?

Thanks!
-Abby


[Non-text portions of this message have been removed]
This is apparently a European motor as it has 380V on it as well as
the 230 or 220. If it has a 6 terminal terminal block on it, wiring
for Delta will be easy.

Let us look at the terminal block as below:

1 2 3

4 5 6

Without removing any of the wires between this terminal block and the
windings in the motor you would simply connect 1 to 4, 2 to 5, and 3
to 6 with jumpers. Then you can bring in the 3 phase power lines to
1,2,3 OR 4,5,6. If it runs in reverse to what you need, simply switch
any two incoming wires to reverse it.

I hope this helps.

Randy Abernathy
4626 Old Stilesboro Road NW
Acworth, GA 30101-4066
Phone / Fax: 770-974-5295
Cell: 678-772-4113
E-mail: Cnc002@...

I furnish technical support, repair, and other related services for
your industrial woodworking machinery. My background as Senior
Service
Engineer for the SCMI Group for nearly fifteen years with factory
training, combines with my extensive background in electronics,
mechanics, pneumatics, electrical and CNC machinery to offer you
needed support for your machinery.


[Non-text portions of this message have been removed]



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