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

 

[ScottyUK]

Hi Allen,

Any chance of a photo of the maker's plate on the motor? You can upload pictures using the green square blobs between the bullet point drop-down and the smiley face.

If you use a VFD then in principle you could program it to suit the motor provided the motor requires a lower voltage than the VFD is capable of producing (i.e. you can "turn the VFD down" a bit).

 

[allencga]

 

[waross]

That looks like a 1 (one) signifying single phase.
110 Volts x 5 Amps = 550 VA. That's about right for a 0.5 HP motor.
You won't find much three phase power at 110 Volts, 60 Hertz.
Measure the current. It it takes close to 5 Amps it is probably OK.

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

 

[jraef]

I thought that was a "1" as well, but look above it on the plate, there are other 1s depicted and they look different.

I think this is what that symbol might mean:

Or... maybe this...

http://www.organsupply.com/assets/Help-Center-Instructions/Meidinger-Blower-Wiring.pdf

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

 

[ScottyUK]

Meidinger are still in business, it can't do any harm to ask if they have a datasheet on their old products. I can't find anything close to it on the current website, but they claim to have data on all their older types. There's an online contact form, or perhaps email them that photo.

https://www.meidinger.ch/en/contact/

info@meidinger.ch

 

[dArsonval]

I'm skeptical the inverted "T" represents information related to the motor winding connection.
It does not appear to be an International Electrotechnical Commission symbol after searching through IEC 60034-8 (Edition 3.1 2014-03)

The stamp that made the mark is also different than the letter T stamped in the top line of the motor name plate.

The URL jraef has posted above pretty much answers the OP's question.

Remove the capacitor and hook it up as shown in the PDF above for a 208-240 three phase connection.

It could be making music tonight!

John

 

[waross]

Almost. The OP wants to power from 120 VAC, so the 108 Volt, delta connection would be the one to use.
If the motor current (as reported by the VFD) is a little too high with the motor configured for 108 Volts, the motor is also rated for 208-240 VAC so the low voltage connection will be suitable for configuration as 120 VAC. That should drop the motor current a little if required.

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

 

[allencga]

Hello All,
Thanks for the replies. Bill to clarify your response and make sure I am understanding all of this correctly. I plan to run this from a VFD that accepts power from a 120V line. Even so, it seems all the VFD's I can find seem to output in 240VAC regardless of the 120V input voltage. Does this mean that I should try the motor first in the 208-240V STAR configuration in the diagram omitting the capacitor? I doubt I will be able to find a VFD that outputs in 120V three phase so the winding will have to be able to accept 240V it seems. Wouldn't the high voltage STAR config be the safe zone for such an experiment. Please forgive my ignorance in all of this as I don't have any experience with the implementation of a VFD. Is there any other equipment recommended to protect the motor like output filters or something? I understand that these VFD's can be a little "spiky" on the output side. This is an older motor that I am sure was never designed specifically with a VFD in mind and I want to protect it if I can. It is very difficult to find a motor shop that will rewind these if something happens.

Allen

 

[jraef]

A VFD can always be programmed to put out any voltage LOWER than the line voltage, just not higher. A VFD converts the incoming AC to DC then recreates an output that the motor "sees" as AC, but it is wholly artificial, so it can be whatever you tell it to be. So yes, you can tell a VFD to put out 110VAC 3 phase.

Now whether or not that motor is really 110V 3 phase is another question. There is no such thing as 110V 3 phase anywhere, so I find it hard to believe anyone would have made a motor like that.


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

 

[davidbeach]

If it had been intended to install the organ on a submarine it would be appropriate to have a 110V 3-phase motor. Otherwise not likely.

 

[waross]

Despite the rating the VFD can not output more voltage than the input.
You can configure the VFD to output the voltage that you need.
If the motor is rated for 240 Volts in star then each winding should be good for up to 139 Volts in delta.
It should be safe to run at 120 Volts despite the 108 Volt rating.
You bring up a good point about VFDs and older motors.
One way to mitigate this is to use a transformer to change the output voltage. 1:2 or 120:240 Volts may work.
Jeff is the one to take it from here. He is much more familiar with filtering methods for VFD outputs.


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

 

[itsmoked]

If it had been intended to install the organ on a submarine it would be appropriate to have a 110V 3-phase motor. Otherwise not likely.

Or 40's era rail cars.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[itsmoked]

I want to know how a VFD with 320V on its DC link could possibly ever put out 120V? I don't believe the ON/OFF pwm can come close to doing that. All it can put out is 0V or 320V. The hideous output waveform may end up delivering something (under the V/Hz curve) to the confused motor iron that leaves it thinking it was seeing something less than 320V but it's not. I don't believe there's any output sensors in drives or even capable of sorting out all the gibberish leaving the drive to come up with a guess about the average voltage let alone someway to control it.

Any motor you're trying to drive will see spikes of at least what the DC link is charged to. If you don't want the windings thrashed with those level of spikes you will need to use an interposed transformer to numerically reduce the 320V spikes to what a 110V would expect. (~155V)

Keith Cress
kcress -

http://www.flaminsystems.com

 

[waross]

He's inputting 120 Volts Keith. He will be seeing 170 Volt peaks.
Keith is correct that the instantaneous Volts out will be either the DC buss voltage or zero volts.
However the effect of the Pulse Width Modulation combined with the VFD source impedance and the motor resistance and impedance will result in an adjustable effective voltage to the motor.
The Pulse Width Modulation will produce an effective sine wave at any frequency and effective voltage within its ratings.

Back in the early 80's I ran across a small portable generator (maybe 3 KVA) that was 110 Volts, three phase delta. That's the only time I have seen it.

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

 

[jraef]

First, a VFD that accepts 120V input will have a voltage doubler on the rectifier so that the DC bus voltage becomes 338VDC, facilitating an output of up to 230VAC PWM.

Second, the output RMS voltage is ALWAYS being artificially manipulated by the drive. Think about it; if a 230V VFD is maintaining a constant V/Hz ratio for a 60Hz motor, what’s the V at 30Hz? All you need do in the VFD programming is tell it that you want 110V at 60Hz and the algorithm calculates the Necessary PWM pattern to deliver that.

One thing that is true is that the peaks of each DC pulse in the PWM output will remain at the DC bus level, in this case 338V. That can sometimes be problematic for older motors that were not built to be run from inverters and made with very low insulation voltage. But that tends to not be an issue on motors designed for 230V.


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

 

[waross]

Thanks Jeff.

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

 

[itsmoked]

Thanks Jeff that was my point exactly as I'm a bit concerned about this ancient motor's insulation. I'd use a transformer at the very least.


Keith Cress
kcress -

http://www.flaminsystems.com

 

[allencga]

Does the suggested "transformer" refer to a device called a "load line reactor" perhaps of the high frequency compensated variety? Is this what is meant by "transformer". I ask out of ignorance because I don't know what all these names for things actually mean.

 

[itsmoked]

Nope allencga.

A transformer actually changes the voltage by stepping (transforming) it up or down as desired.

A reactor removes or reduces fast current changes. They use them to help prevent VFD electrical noise from going back to the source. They help the VFD rectifiers by stretching out the conduction angles reducing the current peaks the rectifiers see. They reduce what the rest of your power systems sees when a VFD is on line. They can protect the VFD from spikes coming in from the supply. Someone may have more VFD application uses too.

Reactors do not change the voltage other than causing some amount of loss, a few volts - they tend to get quite warm.

Keith Cress
kcress -

http://www.flaminsystems.com