RE: [CAD_CAM_EDM_DRO] 3 phase motor math

Randy,

Yes, this would be quite easy.. If there were six connections on the
terminal block.. But there arent. :/
There's only three, as the motor has already been wired internally to
either star or delta configuration.

This was why I wrote all the specs... I'd like to try and work out how
many volts this has been wired for.
If it's not wired for 220V, I've gotta open the motor, find the
star-point and rewire it into delta.

But I was just hoping I could work from the 25 Ohms value to calculate
if it's already in delta, to save all the hassle. Do you know the
formula for this?



-----Original Message-----
From: cnc002@... [mailto:cnc002@...]
Sent: 16 May 2004 20:11
To: CAD_CAM_EDM_DRO@yahoogroups.com
Subject: Re: [CAD_CAM_EDM_DRO] 3 phase motor math


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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