Meidinger Pipe Organ Blower Hook up 1

[allencga]

Greetings!

I have a Swiss built Meidinger blower designed for use in a pipe organ. It came set up with a 80mf capacitor to facilitate operation on 110 VAC SINGLE PHASE supply even though this is technically a six wire three phase motor.
The boiler plate indicates 110 VAC with a symbol like an inverted letter "T" which I am interpreting to mean that the winding should be placed into STAR formation. When I opened the terminal box it appears to have actually been set up in DELTA configuration with the capacitor between L1 and the third phase winding to create the necessary bias for operation from a single phase supply at 110VAC. The motor actually starts and runs in this configuration but I am not sure if it is correct or safe given that the nameplate appears to call for STAR config.

I would like to do away with the capacitor and run this from a VFD That provides three actual phases. I would like to power the input of the VFD from 120VAC single phase. Is this possible given the spec of the motor? How should this motor be connected? STAR or DELTA? and what supply voltage should be supplied from the VFD output? Can this be run on 240VAC? Any recommendations as to specific VFD and other needed equipment would be most appreciated. More specs below:

Meidinger blower Model MFO 1202 NIKX 33 Uv
H.P. 1/2
Period 60Hz
3360 RPM
110 VAC STAR?
5 amp

Checking with an OHM meter shows each individual winding to have impedance of 1.8 ohm end to end or 3.6 ohm per phase in STAR formation as there are always 2 windings in series.

Many thanks
Allen

 

[waross]

And the transformer windings act as a reactor.
At one plant I was at, there were a series of SAGD well pads. Each well pad had a large VFD driving a submersible pump down the hole. With the long lead lengths harmonic overvoltages were a serious concern.
Some pads had filters which included reactors.
Some pads had transformers to match the supply voltage (480 Volts) to the pump voltages (4160 volts).
None of the pads had both a filter and a reactor.

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

 

[allencga]

I would probably like to use reactors going in and out with perhaps high frequency compensation on the output side reactor. Is there a recommended supplier for these?

 

[allencga]

This has been a fascinating and informative discussion and I appreciate the input from everyone.
There is yet another point of interest here that I cannot get my head around.

This truly seems to be a three phase motor with three independent identifiable windings terminating in 6 wires in the terminal box and the windings do not seem interconnected in any way. This is as expected.

I am familiar with the trick of providing TWO AC supply lines of 230V each offset one from the other by 180 electrical degress augmented by a capacitor to bias one of the hot legs to create a "third phase" of sorts. These motors run ok if a little hot in this config due to unavoidable imbalance because of the sign waves not being equidistantly phased.

This motor on the other hand seems purposely designated for operation on 110v meaning literally one hot leg carrying the 110V sign wave, a neutral, and a capacitor and it really does start and run this way. How is this even possible? How is it coming up with three phase functionality having only one hot leg, a neutral and a single capacitor? I would be interesting to know what is going on here.

Incidentally, the inverted "T" from earlier in this thread does appear in a table of electrical symbols and is associated with a special transformer connection featuring center tapping of windings. This is known as a "Scott" transformer and was apparently designed to make old 2 phase motors operable on three phase power systems. I am sure this method languishes in obsolescence by now and doesn't seem applicable to this situation.

Anyway, what's up with this whole set up being operable as it is with a neutral and only one hot leg?

 

[waross]

First do a little reading.
Try the Cowern Papers.
Cowern papers
Perhaps someone else can suggest a good basic text online for three phase systems and vector relationships.
By the way, the capacitor seldom results in a 90 degree phase shift, and the phase shift angle will vary as the value of the capacitor varies.
Once the motor spins up, the back EMF pulls the angle close to 90 degrees for a single phase motor and 120 degrees for a three phase motor.
The motors run hot because one or two phase windings are doing the work of three phase windings.
The winding powered by the capacitor may not be doing its full share.
It depends.

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

 

[dArsonval]

Century had a line of single phase motors with poly-phase lap windings in them.
It's been too long ago to remember specifically what models they were.
I kind of remember they were in cast iron frame configurations.

I agree with Bill. One needs to read up on the subject of motors to understand what makes them run.

If you had the means... one could take a modest size 3-phase motor out of a box,
(say 1 HP or below for purposes of experimentation) and by connecting a motor run capacitor in the proper circuit location,
make it run upon applying a source of single phase alternating current.

It'd be called a Permanent Split-Capacitor Run motor at that point.
PSC motors don't have a lot of locked-rotor torque but they are generally found in fan and blower applications
which correlates with what this pipe organ motor appears to be.

As for that upside down T on the name plate? I do not know what it is intended to represent.
I'll express again it's doubtful it means anything related to how the motor is connected.

(The symbol could be construed as a split winding I guess... for the vertical line is splitting
the horizontal line in half....) Again, I doubt this guess even.

What I want to know is... when you get this thing up and running... after all this discussion...
what URL do we go to... to hear the music?

John ; )

 

[crshears]

And what sort of organ is it? Tracker? Or something else? Is the tuning Baroque, Classical, mean tone temperament, or something else? How many speaking ranks and what are their voices? What is their disposition? How many manuals? Pedal board or not? What wind pressure does it operate under? Existing instrument or new opus? Who is/was the builder?

The blower size suggests more of a chamber, or chapel, or residence organ rather than something in a church sanctuary of any significant size...

CR

"As iron sharpens iron, so one person sharpens another." [Proverbs 27:17, NIV]

 

[dArsonval]

The Op's going to have a research project on his hands to answer the additional questions
posed by crshears. (All great questions by the way ; )

For even more insight or "clouding" into this conversation... another thought comes to mind.
(Not for purposes of hi-jacking the thread.)

The organ motor in topic could also be "loosely" described as a rotary phase converter.

Don't have a lot of time to reference the perfect description because it will interrupt my Cabin Fever,
but if one wants to spend all day surfing the U.S. Patent site, you will eventually find a phase converter
circuit configured similar to the motor in discussion complete, with an authentic description of how it "works".

Here's one URL to get you started:

https://patents.google.com/patent/US4792740?oq=rotary+phase

Opinion: A while back, I remember mentioning that an electric motor today has become
a perfectly designed item, and that the bulk of interest or focus now is in all the complex
electronics that's been invented to run them.

Before the advent of electronic control there were lots of creative [ingenious] ways of powering an insulated conductor
wrapped around a ferrous metal to achieve a mechanical rotation of a member.
Many of these methods fall into the category of lost or forgotten art.

An example of another motor that can rack the brain of the brilliant is the Split-Series D.C. Motor.
It's a reversible direct current motor with 3 exposed connection leads that when powered,
only one field pole is energized.

John