Motor Voltage Change with little obvious markings. 2

Hi Keith.
If it is still wired for 460 Volts it will be quick to re-number.
You have T1, T2, and T3.
You have three groups of two wire.
Break one of the two wire splices open.
You will have continuity from one of the line wires to one of the wires in the splice.
You will have continuity from T1 to T4, and T4 will be connected to T7
You will have continuity from T2 to T5, and T5 will be connected to T8
You will have continuity from T3 to T6, and T6 will be connected to T9
A smart guy like you should have no trouble.

Yes, two heaters was standard for many years, when delta supplies were common.
With the gradual shift to wye supply systems it was found that a wye system was more prone to the types of unbalance that will cause one phase to draw extra current. Motors started burning out when an unbalance happened to cause the extra current on the phase without overload protection.
The codes were changed to require three overload elements.
You are correct, the heaters will have to be changed.
Rather than looking for replacement heaters, I would recommend upgrading to a new, three pole overload relay.
The old two pole overload relay is no longer code compliant.
Bill
--------------------
"Why not the best?"
Jimmy Carter

That motor may be older than you think.
I thought that standard motor ratings had been uprated from 220/440 Volts to 230/460 Volts by the 60's in line with the system uprates from 110/220 Volts to 120/240 Volts.
Can anyone confirm or correct me here?

Bill
--------------------
"Why not the best?"
Jimmy Carter

On your third photo with the vector sketch:
If you draw a curve from T1 to T2 to T3 to T4 to T5 .... to T9, you will see that it forms a spiral. I have found that an easy way to remember the relative wire numbers.
(For a twelve lead generator, just go around one more time to pick up T10, T11 and T12)

Bill
--------------------
"Why not the best?"
Jimmy Carter

Thanks a million Bill! What you described makes perfect sense looking back at the motor schematic.

I hear you on the overload relay. I'm guessing re-wiring is about the same PITA as re-heatering. I may have one kicking around in my office since it's only 1HP.

Thanks again.

Keith Cress
kcress -

The nameplate struck a curiosity for me because the current stamped on the plate would indicate an apparatus rated about 3/4 horsepower.

Agree with Bill as he writes that the motor “…may be older than you think.”

From the GE 5K203E27 model number, it suggests the motor is in a 203 frame configuration.

After the 1952 Re-Rate of NEMA frames, the 203 frame was eliminated.
So, a 1 horsepower motor rated at 1800 RPM manufactured after 1952 would have been in a 182 frame configuration.

Based on the nameplate alone, without seeing the motor itself, the motor could have possibly been manufactured in the 1940s.

In 1951, (before the first NEMA Re-rating of frames) you could buy that motor from Grainger for $59.28.
If you needed a manual starter with it, that would set you back an additional $12.10.

John

Thanks for that information John. I enjoyed seeing it.
Keith, those old NEMA frames were almost indestructible.
With the U frames plugging to stop and DOL reversing was common. Don't try that with a T frame motor.
I haven't seen a plugging switch for decades now.
The pre 1952 NEMA frames were even tougher.
Do you have any information or documents relating to the rise in the standard utility voltages from multiples of 110 Volts to multiples of 120 Volts? I understand that the change was phased in over 20 years at the rate of 1/2 Volt per year.
During the change over the rated voltage of appliances changed every five years.
We had 112 Volts, 115 Volts, 117 Volts and finally 120 Volts.


Bill
--------------------
"Why not the best?"
Jimmy Carter

The NEC change to require OL protection in all 3 phases took place in the 1971 edition, with a "grace period" of 5 years for mfrs to get on board with new devices. I know that last part because when I started in the electrical industry in 1976, my first job at a US Steel plant was seeking out all of the remaining starters with 2 pole OLRs and swapping them out. I had to finish by December 31, 1976. I probably missed a few though...


" We are all here on earth to help others; what on earth the others are here for I don't know." -- W. H. Auden

Facts get buried among myths.

At some point manufacturers began labeling their products as operating at 115/230, 230/460,etc. from 110/220, 220/440 and so on.

All of the above mentioned voltages were standard-system voltage ratings in the year 1928
depending on what side of the transformer one was referring to.

The attached JPEG is from Transformer Construction and Operation, by Emerson G. Reed.
Published 1928 by McGraw-Hill Book Company, Inc.

Perhaps someone from the Power crowd can clarify the history behind re-labeling system voltages.

John

You can read all about the history of the development of the standard for voltages in the Forward of ANSI C84.1-2011
Bottom line, first created in 1942, codified by ANSI in 1954, modified and solidified in 1970 at the levels we use now, tweaked a little now and again, but basically not significantly.


" We are all here on earth to help others; what on earth the others are here for I don't know." -- W. H. Auden

I got the 60 from the owner pointing at it and insisting it meant "1960". Seeing the voltage and 3ph on the line I told him, "Naw, it's 60Hz". He insisted the seller said it was "circa 1960" and that's what it meant. I couldn't see it very well since it was almost 2 feet over my head on a fork lift. Now that I decided to toss it in to show you guys it's "1960" I see very clearly that the stamped label is, of course, showing "CYCLES" LOL



This is what the machine looks like:



Yeah... 1960s? No.. When did cast-iron legs go out of vogue?

And bill, now that I've looked at the winding diagram, your description informs that baby perfectly.

Keith Cress
kcress -

Well, several hundreds of years of combined experience here agrees with you that it is 60 cycles, BUT:-
The customer is always right.
I wonder why GE would dust off a 1940's design and specs to build a motor in 1960? Grin
We've all had customers like that.
By the way, If you ever have to replace that old dog, frame size may be more important than HP.
With a T frame motor, to get similar overload and breakaway torque capability, I would go for twice the HP.
We tended to abuse the U frame motors a lot in the lumber mills.
A U frame motor would accept daily abuse that would quickly destroy a T frame motor.
Those old NEMA frames were even tougher than the U frames.
Also, if the machine is prone to jamming, the O/L relay may not act fast enough to provide protection.
One of the old tricks when going from a U frame to a T frame motor on machines that had a tendency to jam was to add a zero speed switch to cut the power immediately on a jam-up rather than waiting for the O/L relay to respond.
Today a VFD may give protection from stalls.
Bill
--------------------
"Why not the best?"
Jimmy Carter