According to Mark Main :
My Rivett 1020S has a 220/440V 13.4/6.7A 60Hz 5HP 1690RPM motor that is
wired for 480V right now. It's been recommended from this group that
it will be best if I rewire the motor for 240V and so that's what I'm
working on, but I still need some help.
The problem is that not all of the wires to the motor are numbered.
Here's what I know:
The only wires that are numbered are the wires from my power panel
(numbered 1, 2 & 3). These leads connect to the motor wires 1, 2 & 3
respectively for both the high and low volt configurations.
In addition to these 3 power lead connections, my motor is configured
for the high volt configuration, and so it has the following wire
pairs: 4+7, 5+8, and 6+9 (unfortunately these wires are not numbered; I
only know this by the diagram on the motor).
There are also two white wires coming from the motor, one is connected
to wire #2 and the other #3.
I want to wire this for the low volt configuration which is: 1+7, 2+8,
3+9, and 4+5+6.
HERE IS MY CHALLENGE: I only know that 4+7 are paired together, 5+8,
and 6+9, but I don't know their numbers... I only know 1, 2 & 3. Is
there a way using a multi meter or other method to identify what the
wire numbers are?
O.K.
4 should have 1 as the other end and connect to 7
5 should have 2 as the other end and connect to 8
6 should have 3 as the other end and connect to 9
7, 8, and 9 join together inside the motor, after
passing through three windings.
You will have to split the splice between the prospective 4&7
(it may be a 5&8 or a 6&9) check (with an ohmmeter) which one of the 1,
2, or 3 it is connected to, and label it according to the list above.
Also label the one to which it was connected as 7, 8, or 9 as
appropriate. Repeat until all are labeled. (Though you really don't
need to measure the last one you open except for piece of mind.
Or -- if you would like to do it *without* labeling:
Open one splice. Check whether it is connected to 1, 2, or 3
through the motor winding (again with an ohmmeter). leave that one (4,
5, or 6) loose, and connect the other side of the just opened splice (7,
8, or 9), to the other end (1, 2, or 3) of the winding you just
disconnected. Repeat with the other two splices. When you are done,
you will have 1, 2, 3, and three loose wires, which are 4, 5, and 6. It
does not really matter which is which in this case, because you are
simply going to be joining them all together and insulating the joint
anyway.
But just to be kind to the *next* person who has to deal with
this motor, I would suggest that you use the first method -- and while
you're about it, get some aluminum or copper 1/4" line, make a support
arbor, and stamp the numbers 4, 5, 6, 7, 8 and 9 in them, and as you
identify the wires, slip these over the wires and squash with pliers
over the insulation a little back from the splice so they will stay and
can be read years or even decades from now.
You *could* do the measurement without opening any of the
splices, but you will need an ohmmeter which is very good with very low
resistances, as these motor windings will not be far above zero.
It's going to be VERY difficult to identify the wires otherwise because
the motor is huge and not easily removed.
The above are two ways you should be able to do it. I
recommend the first, with the number-stamped collars. (Or -- you can go
to a nearby electrical supply place (the ones which sell to
electricians, not the local Home Depot), and get a little device which
has ten rolls of white tape with black numbers stamped on it. This will
be easier to do, but will probably cost you something like $18.00.
Enjoy,
DoN.
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