For the last two nights, I moved the compressor into the garage and
have been trying to find a good way to run it. This is a Quincy
compressor with a 5-10 HP rated pressure lubricated pump.

http://igor.chudov.com/projects/Quincy-340-Compressor/

I bought it without the motor, it had a 7.5 HP 58 year old motor that
I did not care for anyway, which gave me a nice price reduction from
the seller, who happened to be a super great guy.

The compressor is now powered by a 10 HP Reliance motor that I had in
NOS condition. I reused the old pulley, which I had to bore out, but
with this pulley it only produced 7.5 HP of output since the pulley
and RPM stayed the same.

Installation of the motor is shown he

http://igor.chudov.com/projects/Quin...00-Reassembly/

I have been working on powering this compressor from a VFD. I am
hoping to accomplish several things with a VFD:

1) Running from single phase

2) Quiet starts

3) Being able to vary speed a little bit, so as to either run super
quietly when I do not need much air, which is the usual case, or in
case of high demand to use full 10 HP at higher speed. According to my
simple calculations, it would run at 5 HP output at 40 Hz, 7.5 HP at 60
Hz, and at 10 HP output at 80 Hz. (the top limit is a little more
iffy, but should be close at pressures lower than 145 PSI)

I used the following VFD: Omegapak 10 HP AC Drive bought here for $100

http://cgi.ebay.com/ws/eBayISAPI.dll...m=250360604511

I decided to solve one problem at a time, and tried to use it from a
real three phase input (phase converter).

It was a little bit of a PITA, to put it mildly, as it had a very old
fashioned control interface. But after some pain, printing out the
manual, and going over things a dozen times, I am now at the point
where the drive comfortably runs the motor, gives smooth acceleration,
deceleration and all that.

As a result, this setup is exceptionally quiet and starts nicely and easily.

The next step would be to try to run it from single phase. (the drive
is 3 phase rated)

My plan is as follows. This drive has two separate inputs: one for
control circuit H1 and H2, and another for three phase input L1, L2,
L3. It also has full amperage contacts for the DC bus, + and -.

So what I want to try, is this: feed DC bus directly, through + and -,
from a completely separate rectifier and a huge 2,200 uF, 700V
electrolytic capacitor. (two 2200 uF, 350V caps in series
actually). Feed the control circuit H1/H2 from regular household 220v.

If I am right, and if it works, it would give enough juice to the DC
bus to not phase fault during zero crossings.

I will see.

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On 2009-02-10, Ignoramus17377 wrote:
I used the following VFD: Omegapak 10 HP AC Drive bought here for $100

http://cgi.ebay.com/ws/eBayISAPI.dll...m=250360604511

Manual for the drive is he

http://igor.chudov.com/manuals/Omega...que-Manual.pdf

I

Ignoramus17377 wrote:

My plan is as follows. This drive has two separate inputs: one for
control circuit H1 and H2, and another for three phase input L1, L2,
L3. It also has full amperage contacts for the DC bus, + and -.

So what I want to try, is this: feed DC bus directly, through + and -,
from a completely separate rectifier and a huge 2,200 uF, 700V
electrolytic capacitor. (two 2200 uF, 350V caps in series
actually).
Umm, that's only 1100 uF with the wto in series.

You can look up the rectifier or power block in a
datasheet and see what the rectifier ratings are.
on the VFDs I have used, they sure looked more
than adequate for single phase operation. The
capacitor bank might be the marginal part, so
adding more caps outside would be a good idea for
such a large load.

Jon

On 2009-02-10, Jon Elson wrote:
Ignoramus17377 wrote:

My plan is as follows. This drive has two separate inputs: one for
control circuit H1 and H2, and another for three phase input L1, L2,
L3. It also has full amperage contacts for the DC bus, + and -.

So what I want to try, is this: feed DC bus directly, through + and -,
from a completely separate rectifier and a huge 2,200 uF, 700V
electrolytic capacitor. (two 2200 uF, 350V caps in series
actually).
Umm, that's only 1100 uF with the wto in series.

You can look up the rectifier or power block in a
datasheet and see what the rectifier ratings are.
on the VFDs I have used, they sure looked more
than adequate for single phase operation. The
capacitor bank might be the marginal part, so
adding more caps outside would be a good idea for
such a large load.

You are right about the capacitance. I goofed.

Usually, for single phase operations with three phase rectifier, there
are warnings about overloading the rectifier, so I would rather not
take a risk.

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Ignoramus17377 wrote:

The next step would be to try to run it from single phase. (the drive
is 3 phase rated)

My plan is as follows. This drive has two separate inputs: one for
control circuit H1 and H2, and another for three phase input L1, L2,
L3. It also has full amperage contacts for the DC bus, + and -.

So what I want to try, is this: feed DC bus directly, through + and -,
from a completely separate rectifier and a huge 2,200 uF, 700V
electrolytic capacitor. (two 2200 uF, 350V caps in series
actually). Feed the control circuit H1/H2 from regular household 220v.

If I am right, and if it works, it would give enough juice to the DC
bus to not phase fault during zero crossings.

Maybe I missed it, but why not run the 220 single phase into the mains
inputs and put the pressure switch on the control inputs? It seems like
the simplest way to do it. Also, it sounds like you have the capability
to run the motor at the reduced load which would give you nearly the
recommended de-rate for single phase operation without hanging a high
current, high voltage kludge on the VFD box.

BobH

On 2009-02-10, BobH wrote:

Maybe I missed it, but why not run the 220 single phase into the mains
inputs and put the pressure switch on the control inputs?

The drive fails with "phase fault" if I feed it single phase in its
inputs mand have a motor connected. That's why I wanted to provide
power to the DC bus by separate means.

I will definitely connect the pressure switch to the VFD "forward"
terminal. If everything works according to plan, I will have two
controls:

1) Switch to prevent starts even if pressure switch is closed
2) A potentiometer to select running speed, in the range of 40-80 Hz.
I would then select the potentiometer setting to select quiet, slow
operation vs. a little louder, faster operation.

It seems like the simplest way to do it. Also, it sounds like you
have the capability to run the motor at the reduced load which would
give you nearly the recommended de-rate for single phase operation
without hanging a high current, high voltage kludge on the VFD box.

I wish it was the case.
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Maybe I missed it, but why not run the 220 single phase into the mains
inputs and put the pressure switch on the control inputs?

The drive fails with "phase fault" if I feed it single phase in its
inputs mand have a motor connected. That's why I wanted to provide
power to the DC bus by separate means.
I had this issue on my hitachi SJ300 drive. Hooking the second 220 leg
to both L2 and L3 worked for me. YMMV

Karl

On Tue, 10 Feb 2009 12:12:14 -0500, Karl Townsend wrote:

Maybe I missed it, but why not run the 220 single phase into the mains
inputs and put the pressure switch on the control inputs?

The drive fails with "phase fault" if I feed it single phase in its
inputs mand have a motor connected. That's why I wanted to provide
power to the DC bus by separate means.
I had this issue on my hitachi SJ300 drive. Hooking the second 220 leg
to both L2 and L3 worked for me. YMMV

Seems that it might not work, but worth a try, I will try it. Thanks.
In any case, if I need to get full power out of this drive, which I
do, I would need to supplant the rectifier.

i

On Tue, 10 Feb 2009 12:12:14 -0500, Karl Townsend
wrote:


Maybe I missed it, but why not run the 220 single phase into the mains
inputs and put the pressure switch on the control inputs?

The drive fails with "phase fault" if I feed it single phase in its
inputs mand have a motor connected. That's why I wanted to provide
power to the DC bus by separate means.
I had this issue on my hitachi SJ300 drive. Hooking the second 220 leg
to both L2 and L3 worked for me. YMMV

Karl


Indeed...a jumper from L3 to L2 often works. Not always..but often

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On Tue, 10 Feb 2009 09:52:31 -0800, Gunner Asch wrote:
On Tue, 10 Feb 2009 12:12:14 -0500, Karl Townsend
wrote:


Maybe I missed it, but why not run the 220 single phase into the mains
inputs and put the pressure switch on the control inputs?

The drive fails with "phase fault" if I feed it single phase in its
inputs mand have a motor connected. That's why I wanted to provide
power to the DC bus by separate means.
I had this issue on my hitachi SJ300 drive. Hooking the second 220 leg
to both L2 and L3 worked for me. YMMV

Karl


Indeed...a jumper from L3 to L2 often works. Not always..but often

The reason why I think that it will not work is this: the drive
reports "phase fault" only when connected to the motor. If it is not
connected to the motor, it does not phase fault. This means that they
detect phase fault based on dips in the bus voltage. This is also
corroborated by the manual.

i

On 2009-02-10, Ignoramus5289 wrote:
On 2009-02-10, BobH wrote:

Maybe I missed it, but why not run the 220 single phase into the mains
inputs and put the pressure switch on the control inputs?

The drive fails with "phase fault" if I feed it single phase in its
inputs mand have a motor connected. That's why I wanted to provide
power to the DC bus by separate means.

Hmm ... what have you done with the third input? Often, it is
necessary to strap together two of the three inputs when running from
single phase input to prevent such faults. It is complaining that one
of the power input leads is open circuited. Usually, the first two are
used for actual power input and the third is jumpered to the adjacent
terminal.

I will definitely connect the pressure switch to the VFD "forward"
terminal. If everything works according to plan, I will have two
controls:

1) Switch to prevent starts even if pressure switch is closed
2) A potentiometer to select running speed, in the range of 40-80 Hz.
I would then select the potentiometer setting to select quiet, slow
operation vs. a little louder, faster operation.

Hmm ... why not make that a three position switch with a string
of resistors to emulate different pot settings. Maybe make it a double
deck four position switch, so you can have stop as one of the
positions?

Good Luck,
DoN.

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Indeed...a jumper from L3 to L2 often works. Not always..but often

The reason why I think that it will not work is this: the drive
reports "phase fault" only when connected to the motor. If it is not
connected to the motor, it does not phase fault. This means that they
detect phase fault based on dips in the bus voltage. This is also
corroborated by the manual.

i
In that case, try a large capacitor on the bus??

Karl

On 2009-02-11, DoN. Nichols wrote:
On 2009-02-10, Ignoramus5289 wrote:
On 2009-02-10, BobH wrote:

Maybe I missed it, but why not run the 220 single phase into the mains
inputs and put the pressure switch on the control inputs?

The drive fails with "phase fault" if I feed it single phase in its
inputs mand have a motor connected. That's why I wanted to provide
power to the DC bus by separate means.

Hmm ... what have you done with the third input? Often, it is
necessary to strap together two of the three inputs when running from
single phase input to prevent such faults. It is complaining that one
of the power input leads is open circuited. Usually, the first two are
used for actual power input and the third is jumpered to the adjacent
terminal.

This one phase faults when it sees voltage dip on the DC bus.

I will definitely connect the pressure switch to the VFD "forward"
terminal. If everything works according to plan, I will have two
controls:

1) Switch to prevent starts even if pressure switch is closed
2) A potentiometer to select running speed, in the range of 40-80 Hz.
I would then select the potentiometer setting to select quiet, slow
operation vs. a little louder, faster operation.

Hmm ... why not make that a three position switch with a string
of resistors to emulate different pot settings. Maybe make it a double
deck four position switch, so you can have stop as one of the
positions?

Why, a potentiometer is a better match for this application. I would
mount it right on the pressure switch.

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On 2009-02-11, Karl Townsend wrote:

Indeed...a jumper from L3 to L2 often works. Not always..but often

The reason why I think that it will not work is this: the drive
reports "phase fault" only when connected to the motor. If it is not
connected to the motor, it does not phase fault. This means that they
detect phase fault based on dips in the bus voltage. This is also
corroborated by the manual.

i
In that case, try a large capacitor on the bus??


That's what I want to do, along with a bigger rectifier.
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Why not use a modulating control to adjust the speed of the motor? Fed from
the enable of your pressure switch, the control would adjust a 0-10vdc or a
4-20mA signal, which most VFD's can use. The greater the deviation from
setpoint, the faster the motor runs.
An L91A1035 Honeywell or a P7810. They are used to control the firing rate
of modulating burners. I think I have one of each molding in the basement.
If you would like to try one let me know.

Steve

"Ignoramus7440" wrote in message
...
On 2009-02-11, DoN. Nichols wrote:
On 2009-02-10, Ignoramus5289 wrote:
On 2009-02-10, BobH wrote:

Maybe I missed it, but why not run the 220 single phase into the mains
inputs and put the pressure switch on the control inputs?

The drive fails with "phase fault" if I feed it single phase in its
inputs mand have a motor connected. That's why I wanted to provide
power to the DC bus by separate means.

Hmm ... what have you done with the third input? Often, it is
necessary to strap together two of the three inputs when running from
single phase input to prevent such faults. It is complaining that one
of the power input leads is open circuited. Usually, the first two are
used for actual power input and the third is jumpered to the adjacent
terminal.

This one phase faults when it sees voltage dip on the DC bus.

I will definitely connect the pressure switch to the VFD "forward"
terminal. If everything works according to plan, I will have two
controls:

1) Switch to prevent starts even if pressure switch is closed
2) A potentiometer to select running speed, in the range of 40-80 Hz.
I would then select the potentiometer setting to select quiet, slow
operation vs. a little louder, faster operation.

Hmm ... why not make that a three position switch with a string
of resistors to emulate different pot settings. Maybe make it a double
deck four position switch, so you can have stop as one of the
positions?

Why, a potentiometer is a better match for this application. I would
mount it right on the pressure switch.

--
Due to extreme spam originating from Google Groups, and their
inattention
to spammers, I and many others block all articles originating
from Google Groups. If you want your postings to be seen by
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posting on Usenet.
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Ignoramus7440 writes:

Hmm ... why not make that a three position switch with a string
of resistors to emulate different pot settings. Maybe make it a double
deck four position switch, so you can have stop as one of the
positions?

Why, a potentiometer is a better match for this application. I would
mount it right on the pressure switch.


One issue is, what happens when the pot momentarily opens?
(Many pots are ...noisy...). One approach is a number
of resistors in series, and switches to short them out.


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On 2009-02-12, David Lesher wrote:
Ignoramus7440 writes:

Hmm ... why not make that a three position switch with a string
of resistors to emulate different pot settings. Maybe make it a double
deck four position switch, so you can have stop as one of the
positions?

Why, a potentiometer is a better match for this application. I would
mount it right on the pressure switch.


One issue is, what happens when the pot momentarily opens?
(Many pots are ...noisy...). One approach is a number
of resistors in series, and switches to short them out.

This drive is designed to be used with a pot. They have gotten these
wrinkles ironed out.

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On 2009-02-11, SnA Higgins wrote:
Why not use a modulating control to adjust the speed of the motor? Fed from
the enable of your pressure switch, the control would adjust a 0-10vdc or a
4-20mA signal, which most VFD's can use. The greater the deviation from
setpoint, the faster the motor runs.
An L91A1035 Honeywell or a P7810. They are used to control the firing rate
of modulating burners. I think I have one of each molding in the basement.
If you would like to try one let me know.

Steve, it is a very interesting thought. I also considered something
similar, but I decided that manual control is more suitable for my
needs. In my instance, it boils down to how much air I need vs. how
much noise I want, as well as pump life, which is a human judgment.

For example, if I was using an air ratchet, I would set it to lowest
speed, if I was using an air hammer continuously, I would set it to
highest.

It is a more idiot proof approach. But your thought has a very solid
foundation and would be very appropriate in an industrial setting.

i

Steve

"Ignoramus7440" wrote in message
...
On 2009-02-11, DoN. Nichols wrote:
On 2009-02-10, Ignoramus5289 wrote:
On 2009-02-10, BobH wrote:

Maybe I missed it, but why not run the 220 single phase into the mains
inputs and put the pressure switch on the control inputs?

The drive fails with "phase fault" if I feed it single phase in its
inputs mand have a motor connected. That's why I wanted to provide
power to the DC bus by separate means.

Hmm ... what have you done with the third input? Often, it is
necessary to strap together two of the three inputs when running from
single phase input to prevent such faults. It is complaining that one
of the power input leads is open circuited. Usually, the first two are
used for actual power input and the third is jumpered to the adjacent
terminal.

This one phase faults when it sees voltage dip on the DC bus.

I will definitely connect the pressure switch to the VFD "forward"
terminal. If everything works according to plan, I will have two
controls:

1) Switch to prevent starts even if pressure switch is closed
2) A potentiometer to select running speed, in the range of 40-80 Hz.
I would then select the potentiometer setting to select quiet, slow
operation vs. a little louder, faster operation.

Hmm ... why not make that a three position switch with a string
of resistors to emulate different pot settings. Maybe make it a double
deck four position switch, so you can have stop as one of the
positions?

Why, a potentiometer is a better match for this application. I would
mount it right on the pressure switch.




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Due to extreme spam originating from Google Groups, and their inattention
to spammers, I and many others block all articles originating
from Google Groups. If you want your postings to be seen by
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posting on Usenet.
http://improve-usenet.org/

On 2009-02-11, Ignoramus7440 wrote:
On 2009-02-11, DoN. Nichols wrote:

[ ... ]

Hmm ... what have you done with the third input? Often, it is
necessary to strap together two of the three inputs when running from
single phase input to prevent such faults. It is complaining that one
of the power input leads is open circuited. Usually, the first two are
used for actual power input and the third is jumpered to the adjacent
terminal.

This one phase faults when it sees voltage dip on the DC bus.

O.K. Perhaps a bit more capacitance?

I will definitely connect the pressure switch to the VFD "forward"
terminal. If everything works according to plan, I will have two
controls:

1) Switch to prevent starts even if pressure switch is closed
2) A potentiometer to select running speed, in the range of 40-80 Hz.
I would then select the potentiometer setting to select quiet, slow
operation vs. a little louder, faster operation.

Hmm ... why not make that a three position switch with a string
of resistors to emulate different pot settings. Maybe make it a double
deck four position switch, so you can have stop as one of the
positions?

Why, a potentiometer is a better match for this application. I would
mount it right on the pressure switch.

But this *is* a potentiometer -- just with three fixed settings.

You only want to select three speeds don't you, not just any
speed? The switch would be like this:

ref V --+ from VFD
|

R1


|
+------------+
| |
|
|
R2 O

|
+----------O -------O----- to control input on VFD
| \
\
O \
R3 | O \
| \
| | \
+------------+ \
| +------O \
| \
R4 | \
+---O --------O------ To forward switch input
| on VFD
+---------------|
___ Control +------O
- ground O


The sum of R1 through R4 is the same value as the recommended
pot value (5K or perhaps 1K), and the individual values are selected to
give the specific speeds which you want -- so there is no problem with
the knob on the pot vibrating and changing your compressor's speed
during a long run.

And the second deck is used to switch on the motor FWD in the
top three positions, (circuit here assumes that you need to ground the
pin to start the motor -- change as necessary.

This gives you a single control which does all that you need,
and is unlikely to change setting during a long run.

Enjoy,
DoN.

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