The 10 HP compressor is now in my yard. Looking good, but needs a
little cleaning.

I will hopefully receive the VFD on Friday or so. It is a Siemens SED2
18.5 kW rated drive. Assuming it works, I have to set its parameters
and here's where I need a little bit of wisdom.

Specifically, my question is how do I set the acceleration ramp-up so
that it works nicely with the unloaders. My own thinking is that I
should accelerate slowly almost up to the speed when unloaders kick
in, and then accelerate as fast as I can once unloaders do kick in and
the pump starts pumping. Any idea what is the speed when unloaders
kick in?

thanks

i

On Oct 23, 9:01 am, Ignoramus705
wrote:
The 10 HP compressor is now in my yard. Looking good, but needs a
little cleaning.

I will hopefully receive the VFD on Friday or so. It is a Siemens SED2
18.5 kW rated drive. Assuming it works, I have to set its parameters
and here's where I need a little bit of wisdom.

Specifically, my question is how do I set the acceleration ramp-up so
that it works nicely with the unloaders. My own thinking is that I
should accelerate slowly almost up to the speed when unloaders kick
in, and then accelerate as fast as I can once unloaders do kick in and
the pump starts pumping. Any idea what is the speed when unloaders
kick in?

thanks

i

Hi.
Just for reference, our 5 hp, 220 volt 3 phase, compressor seems to
have zero ramp up. At least it's not detectable when it starts. Seems
to go from zero to full speed instantly. The tank is 60 gal. So,
really don't think acceleration on your compressor should be a
consideration.

Best regards,
Paul

wrote:

On Oct 23, 9:01 am, Ignoramus705
wrote:
The 10 HP compressor is now in my yard. Looking good, but needs a
little cleaning.

I will hopefully receive the VFD on Friday or so. It is a Siemens SED2
18.5 kW rated drive. Assuming it works, I have to set its parameters
and here's where I need a little bit of wisdom.

Specifically, my question is how do I set the acceleration ramp-up so
that it works nicely with the unloaders. My own thinking is that I
should accelerate slowly almost up to the speed when unloaders kick
in, and then accelerate as fast as I can once unloaders do kick in and
the pump starts pumping. Any idea what is the speed when unloaders
kick in?

thanks

i

Hi.
Just for reference, our 5 hp, 220 volt 3 phase, compressor seems to
have zero ramp up. At least it's not detectable when it starts. Seems
to go from zero to full speed instantly. The tank is 60 gal. So,
really don't think acceleration on your compressor should be a
consideration.

Best regards,
Paul

Presumably you're feeding your compressor "real" three phase power. When
using three phase from a VFD functioning as a phase converter from
single phase power in a residential setting a little soft start helps
reduce the lights dimming and SWMBO bitching.

Iggy - Are the unloaders speed or time controlled? If speed, your plan
sounds good, if time, get things up to speed in time for the unloaders
to kick in. Either way I doubt there will be much benefit to a ramp up
of more than 1 second. You can always put an amp probe on it and see
what peak current is with zero ramp up and at different ramp rates and
see what is the best fit.

On 2007-10-23, Pete C. wrote:
wrote:

On Oct 23, 9:01 am, Ignoramus705
wrote:
The 10 HP compressor is now in my yard. Looking good, but needs a
little cleaning.

I will hopefully receive the VFD on Friday or so. It is a Siemens SED2
18.5 kW rated drive. Assuming it works, I have to set its parameters
and here's where I need a little bit of wisdom.

Specifically, my question is how do I set the acceleration ramp-up so
that it works nicely with the unloaders. My own thinking is that I
should accelerate slowly almost up to the speed when unloaders kick
in, and then accelerate as fast as I can once unloaders do kick in and
the pump starts pumping. Any idea what is the speed when unloaders
kick in?

thanks

i

Hi.
Just for reference, our 5 hp, 220 volt 3 phase, compressor seems to
have zero ramp up. At least it's not detectable when it starts. Seems
to go from zero to full speed instantly. The tank is 60 gal. So,
really don't think acceleration on your compressor should be a
consideration.

Best regards,
Paul

Presumably you're feeding your compressor "real" three phase power. When
using three phase from a VFD functioning as a phase converter from
single phase power in a residential setting a little soft start helps
reduce the lights dimming and SWMBO bitching.

My plan, to be exact, is to put this compressor on a VFD so that it
can be run without any phase converter. My setup features a 10 HP
compressor motor, 15 HP head (spun 33% slower), and a 25 HP rated VFD.

Just to be a little redundant, I did call Quincy today and gave them
my serial number etc, they confirmed that this is a 15 horsepower
head, properly slowed down so that it can be driven by a 10 HP motor.

So, I want the VFD to take 1 phase in, and to make 3 phase out for the
motor to run.

Iggy - Are the unloaders speed or time controlled? If speed, your plan
sounds good, if time, get things up to speed in time for the unloaders
to kick in.

I would guess they are speed controlled.

Either way I doubt there will be much benefit to a ramp up of more
than 1 second. You can always put an amp probe on it and see what
peak current is with zero ramp up and at different ramp rates and
see what is the best fit.

1 second seemt to be the best all around spin up time, to me
personally. Not too slow, not too fast, does not startle people as
much and is gentle on everything.

i

wrote:

Just for reference, our 5 hp, 220 volt 3 phase, compressor seems to
have zero ramp up. At least it's not detectable when it starts. Seems
to go from zero to full speed instantly. The tank is 60 gal. So,
really don't think acceleration on your compressor should be a
consideration.

If one is using a VFD to drive it, and the VFD has ramp-up capabilities,
might as well use them - if nothing else (and there are other things,
such as lubrication distribution) it reduces the starting surge of
current drawn from the wall. If you're building compressors and trying
to maximize profit, there won't be a VFD there, so there won't be a ramp
on start-up. Turning one-phase into three-phase to power surplus
equipment changes the economics, and thus the options...

Then you get into other neat things you can do with a VFD, if you get
the control electronics (and more sensors than are typical) lined up
right - run the compressor faster or slower depending on how much air
you are using (well, probably based more on tank pressure, or rate of
change of tank pressure, really), idling it down (and perhaps unloading,
if the unloaders are electrical) without shutting off until some period
of time passes so it's not shutting off and turning on in the middle of
work, etc. All much fancier than the standard setup, and somewhat
violating KISS...

--
Cats, coffee, chocolate...vices to live by

On 2007-10-23, Ecnerwal wrote:
wrote:

Just for reference, our 5 hp, 220 volt 3 phase, compressor seems to
have zero ramp up. At least it's not detectable when it starts. Seems
to go from zero to full speed instantly. The tank is 60 gal. So,
really don't think acceleration on your compressor should be a
consideration.

If one is using a VFD to drive it, and the VFD has ramp-up capabilities,
might as well use them - if nothing else (and there are other things,
such as lubrication distribution) it reduces the starting surge of
current drawn from the wall. If you're building compressors and trying
to maximize profit, there won't be a VFD there, so there won't be a ramp
on start-up. Turning one-phase into three-phase to power surplus
equipment changes the economics, and thus the options...

Then you get into other neat things you can do with a VFD, if you get
the control electronics (and more sensors than are typical) lined up
right - run the compressor faster or slower depending on how much air
you are using (well, probably based more on tank pressure, or rate of
change of tank pressure, really), idling it down (and perhaps unloading,
if the unloaders are electrical) without shutting off until some period
of time passes so it's not shutting off and turning on in the middle of
work, etc. All much fancier than the standard setup, and somewhat
violating KISS...


Just a ramp up is fine with me. Running it slower may create motor
cooling issues.

i

Ignoramus705 wrote:
The 10 HP compressor is now in my yard. Looking good, but needs a
little cleaning.

I will hopefully receive the VFD on Friday or so. It is a Siemens SED2
18.5 kW rated drive. Assuming it works, I have to set its parameters
and here's where I need a little bit of wisdom.

Specifically, my question is how do I set the acceleration ramp-up so
that it works nicely with the unloaders. My own thinking is that I
should accelerate slowly almost up to the speed when unloaders kick
in, and then accelerate as fast as I can once unloaders do kick in and
the pump starts pumping. Any idea what is the speed when unloaders
kick in?
Depending on the unloader system, it may be entirely pneumatic time delay,
or hydraulic. Especially if hydraulic, it will not be at a specific
time. The first start of the day will take longer. Just set the ramp
up so the lights don't dim too much when spinning up. Roughly one
second might be a good starting guess. I can't see any reason to not be
fully at speed (60 Hz) before the compressor gets loaded.

Jon

Ignoramus705 wrote:
On 2007-10-23, Pete C. wrote:


Iggy - Are the unloaders speed or time controlled? If speed, your plan
sounds good, if time, get things up to speed in time for the unloaders
to kick in.


I would guess they are speed controlled.

I don't believe Quincy has ever used a centrifugal unloader control.
The two (non-electrical) systems they have are pure pneumatic (where the
motor pretty much runs all the time, and the control unloads the
compressor as the primary pressure control mechanism) and
hydro-pneumatic, where the unloader cuts out and allows the pump to work
when the oil pressure is built up. This usually takes about 2-3
seconds, depending on how long the pump has been stopped. On your pix
from a couple days ago, I didn't see anything that looked like
electrical controls for the unloader. Since the unloaders are pneumatic
(I think) you could always control them with a solenoid valve and a time
delay relay.

Jon

I called Siemens, spoke to their engineer and he confirmed that this
drive should work with this motor. I expected that, but it is good
news.

i

On 2007-10-23, Jon Elson wrote:


Ignoramus705 wrote:
On 2007-10-23, Pete C. wrote:


Iggy - Are the unloaders speed or time controlled? If speed, your plan
sounds good, if time, get things up to speed in time for the unloaders
to kick in.


I would guess they are speed controlled.

I don't believe Quincy has ever used a centrifugal unloader control.
The two (non-electrical) systems they have are pure pneumatic (where the
motor pretty much runs all the time, and the control unloads the
compressor as the primary pressure control mechanism) and
hydro-pneumatic, where the unloader cuts out and allows the pump to work
when the oil pressure is built up. This usually takes about 2-3
seconds, depending on how long the pump has been stopped. On your pix
from a couple days ago, I didn't see anything that looked like
electrical controls for the unloader. Since the unloaders are pneumatic
(I think) you could always control them with a solenoid valve and a time
delay relay.

Jon


Jon, I will double check tonight if I get some free time. Thanks. I
have no idea how unloaders work. As for hydraulic control, that would
require the oil pump? But this compressor is splash lubricated.

i

On 2007-10-23, Jon Elson wrote:


Ignoramus705 wrote:
The 10 HP compressor is now in my yard. Looking good, but needs a
little cleaning.

I will hopefully receive the VFD on Friday or so. It is a Siemens SED2
18.5 kW rated drive. Assuming it works, I have to set its parameters
and here's where I need a little bit of wisdom.

Specifically, my question is how do I set the acceleration ramp-up so
that it works nicely with the unloaders. My own thinking is that I
should accelerate slowly almost up to the speed when unloaders kick
in, and then accelerate as fast as I can once unloaders do kick in and
the pump starts pumping. Any idea what is the speed when unloaders
kick in?
Depending on the unloader system, it may be entirely pneumatic time delay,
or hydraulic. Especially if hydraulic, it will not be at a specific
time. The first start of the day will take longer. Just set the ramp
up so the lights don't dim too much when spinning up. Roughly one
second might be a good starting guess. I can't see any reason to not be
fully at speed (60 Hz) before the compressor gets loaded.


1 second is definitely what I will start with. My mill also has a 1
second delay, it feels very nice.

i

Ignoramus705 wrote:

On 2007-10-23, Pete C. wrote:
wrote:

On Oct 23, 9:01 am, Ignoramus705
wrote:
The 10 HP compressor is now in my yard. Looking good, but needs a
little cleaning.

I will hopefully receive the VFD on Friday or so. It is a Siemens SED2
18.5 kW rated drive. Assuming it works, I have to set its parameters
and here's where I need a little bit of wisdom.

Specifically, my question is how do I set the acceleration ramp-up so
that it works nicely with the unloaders. My own thinking is that I
should accelerate slowly almost up to the speed when unloaders kick
in, and then accelerate as fast as I can once unloaders do kick in and
the pump starts pumping. Any idea what is the speed when unloaders
kick in?

thanks

i

Hi.
Just for reference, our 5 hp, 220 volt 3 phase, compressor seems to
have zero ramp up. At least it's not detectable when it starts. Seems
to go from zero to full speed instantly. The tank is 60 gal. So,
really don't think acceleration on your compressor should be a
consideration.

Best regards,
Paul

Presumably you're feeding your compressor "real" three phase power. When
using three phase from a VFD functioning as a phase converter from
single phase power in a residential setting a little soft start helps
reduce the lights dimming and SWMBO bitching.

My plan, to be exact, is to put this compressor on a VFD so that it
can be run without any phase converter. My setup features a 10 HP
compressor motor, 15 HP head (spun 33% slower), and a 25 HP rated VFD.

Just to be a little redundant, I did call Quincy today and gave them
my serial number etc, they confirmed that this is a 15 horsepower
head, properly slowed down so that it can be driven by a 10 HP motor.

So, I want the VFD to take 1 phase in, and to make 3 phase out for the
motor to run.

Um, that reply was to the other poster his 3ph compressor with no
VFD or soft start.


Iggy - Are the unloaders speed or time controlled? If speed, your plan
sounds good, if time, get things up to speed in time for the unloaders
to kick in.

I would guess they are speed controlled.

Seems unlikely given the other replies.


Either way I doubt there will be much benefit to a ramp up of more
than 1 second. You can always put an amp probe on it and see what
peak current is with zero ramp up and at different ramp rates and
see what is the best fit.

1 second seemt to be the best all around spin up time, to me
personally. Not too slow, not too fast, does not startle people as
much and is gentle on everything.

i

1 Second is probably good, however if this is your winter project, some
peak amp numbers at different soft start rates would make an interesting
post...

On 2007-10-23, Pete C. wrote:
Ignoramus705 wrote:

On 2007-10-23, Pete C. wrote:
wrote:

On Oct 23, 9:01 am, Ignoramus705
wrote:
The 10 HP compressor is now in my yard. Looking good, but needs a
little cleaning.

I will hopefully receive the VFD on Friday or so. It is a Siemens SED2
18.5 kW rated drive. Assuming it works, I have to set its parameters
and here's where I need a little bit of wisdom.

Specifically, my question is how do I set the acceleration ramp-up so
that it works nicely with the unloaders. My own thinking is that I
should accelerate slowly almost up to the speed when unloaders kick
in, and then accelerate as fast as I can once unloaders do kick in and
the pump starts pumping. Any idea what is the speed when unloaders
kick in?

thanks

i

Hi.
Just for reference, our 5 hp, 220 volt 3 phase, compressor seems to
have zero ramp up. At least it's not detectable when it starts. Seems
to go from zero to full speed instantly. The tank is 60 gal. So,
really don't think acceleration on your compressor should be a
consideration.

Best regards,
Paul

Presumably you're feeding your compressor "real" three phase power. When
using three phase from a VFD functioning as a phase converter from
single phase power in a residential setting a little soft start helps
reduce the lights dimming and SWMBO bitching.

My plan, to be exact, is to put this compressor on a VFD so that it
can be run without any phase converter. My setup features a 10 HP
compressor motor, 15 HP head (spun 33% slower), and a 25 HP rated VFD.

Just to be a little redundant, I did call Quincy today and gave them
my serial number etc, they confirmed that this is a 15 horsepower
head, properly slowed down so that it can be driven by a 10 HP motor.

So, I want the VFD to take 1 phase in, and to make 3 phase out for the
motor to run.

Um, that reply was to the other poster his 3ph compressor with no
VFD or soft start.

Yes, you are right.


Iggy - Are the unloaders speed or time controlled? If speed, your plan
sounds good, if time, get things up to speed in time for the unloaders
to kick in.

I would guess they are speed controlled.

Seems unlikely given the other replies.

Looks like I was wrong here, too.


Either way I doubt there will be much benefit to a ramp up of more
than 1 second. You can always put an amp probe on it and see what
peak current is with zero ramp up and at different ramp rates and
see what is the best fit.

1 second seemt to be the best all around spin up time, to me
personally. Not too slow, not too fast, does not startle people as
much and is gentle on everything.

i

1 Second is probably good, however if this is your winter project, some
peak amp numbers at different soft start rates would make an interesting
post...

I went through this once with my phase converter. I will report my
results once I get somewhere.

i

Ignoramus705 wrote:
{big snip}
Jon, I will double check tonight if I get some free time. Thanks. I
have no idea how unloaders work. As for hydraulic control, that would
require the oil pump? But this compressor is splash lubricated.

i

Splash lubricated Quincy? Really?

On 2007-10-24, Jeff wrote:
Ignoramus705 wrote:
{big snip}
Jon, I will double check tonight if I get some free time. Thanks. I
have no idea how unloaders work. As for hydraulic control, that would
require the oil pump? But this compressor is splash lubricated.

i

Splash lubricated Quincy? Really?

Really. QR series pumps are pressure lubricated, most others are
splash.

i

Jeff wrote:
Ignoramus705 wrote:
{big snip}
Jon, I will double check tonight if I get some free time. Thanks. I
have no idea how unloaders work. As for hydraulic control, that would
require the oil pump? But this compressor is splash lubricated.

i

Splash lubricated Quincy? Really?

Really!
http://www.quincycompressor.com/reciprocating.html

Just below Pressure Lubricated and above Oil-less.

In article ,
Ignoramus705 wrote:

The 10 HP compressor is now in my yard. Looking good, but needs a
little cleaning.

I will hopefully receive the VFD on Friday or so. It is a Siemens SED2
18.5 kW rated drive. Assuming it works, I have to set its parameters
and here's where I need a little bit of wisdom.

Specifically, my question is how do I set the acceleration ramp-up so
that it works nicely with the unloaders. My own thinking is that I
should accelerate slowly almost up to the speed when unloaders kick
in, and then accelerate as fast as I can once unloaders do kick in and
the pump starts pumping. Any idea what is the speed when unloaders
kick in?

I'd be tempted to call Quincy and ask them.

Joe Gwinn

On 2007-10-24, Joseph Gwinn wrote:
In article ,
Ignoramus705 wrote:

The 10 HP compressor is now in my yard. Looking good, but needs a
little cleaning.

I will hopefully receive the VFD on Friday or so. It is a Siemens SED2
18.5 kW rated drive. Assuming it works, I have to set its parameters
and here's where I need a little bit of wisdom.

Specifically, my question is how do I set the acceleration ramp-up so
that it works nicely with the unloaders. My own thinking is that I
should accelerate slowly almost up to the speed when unloaders kick
in, and then accelerate as fast as I can once unloaders do kick in and
the pump starts pumping. Any idea what is the speed when unloaders
kick in?

I'd be tempted to call Quincy and ask them.

Joe Gwinn

I called Siemens actually, their engineer did not seem like the utmost
expert in the field, but he said that it will probably work. I will
see. I am going to post a separate message about how I ran this Quincy
today.

i

Ignoramus705 wrote:

On 2007-10-24, Joseph Gwinn wrote:
In article ,
Ignoramus705 wrote:

The 10 HP compressor is now in my yard. Looking good, but needs a
little cleaning.

I will hopefully receive the VFD on Friday or so. It is a Siemens SED2
18.5 kW rated drive. Assuming it works, I have to set its parameters
and here's where I need a little bit of wisdom.

Specifically, my question is how do I set the acceleration ramp-up so
that it works nicely with the unloaders. My own thinking is that I
should accelerate slowly almost up to the speed when unloaders kick
in, and then accelerate as fast as I can once unloaders do kick in and
the pump starts pumping. Any idea what is the speed when unloaders
kick in?

I'd be tempted to call Quincy and ask them.

Joe Gwinn

I called Siemens actually, their engineer did not seem like the utmost
expert in the field, but he said that it will probably work. I will
see. I am going to post a separate message about how I ran this Quincy
today.

i

You want the motor to get up to speed before the unloader cuts off. You
should have the vfd acellerate as fast it is able to do without tripping
the breakers.

John