Packing line upgrade time...

My bin dump water pump is the largest noise maker in the system. I
quickly tried a VFD a couple years ago and it SQUEALED far worse than
the excess motor noise. Just as pleasant as listening to chalk squeal
on a blackboard.

Anyway, this time I want to buy a 1/2 hp VFD that doesn't have carrier
wave noise. Suggestions? BTW, the unit will be located 75' of wire
from the motor. Is a reactor needed in this case?

Karl

"Karl Townsend" wrote in message
...
Packing line upgrade time...

My bin dump water pump is the largest noise maker in the system. I
quickly tried a VFD a couple years ago and it SQUEALED far worse than
the excess motor noise. Just as pleasant as listening to chalk squeal
on a blackboard.

Anyway, this time I want to buy a 1/2 hp VFD that doesn't have carrier
wave noise. Suggestions? BTW, the unit will be located 75' of wire
from the motor. Is a reactor needed in this case?

Karl


What is the actual source of the noise?

I run a 1/2HP VFD and 5HP VFD in the high power side cabinet on my Hurco,
and both are virtually silent. The servo dithering is louder than either
one.

On Mon, 19 Aug 2013 14:22:08 -0500, Karl Townsend
wrote:

Packing line upgrade time...

My bin dump water pump is the largest noise maker in the system. I
quickly tried a VFD a couple years ago and it SQUEALED far worse than
the excess motor noise. Just as pleasant as listening to chalk squeal
on a blackboard.

Anyway, this time I want to buy a 1/2 hp VFD that doesn't have carrier
wave noise. Suggestions? BTW, the unit will be located 75' of wire
from the motor. Is a reactor needed in this case?

Karl

Most..not all...but most VFDs do NOT squeal. Of all the ones Ive
installed over the past 16 yrs...only one..a Hitachi 3/4hp on a drill
press squealed.

Automationdirect.com is a very good place for inexpensive drives

http://www.automationdirect.com/adc/...-Hz_Control%29

http://www.automationdirect.com/adc/...-Hz_Control%29

The GS1 drives will probably do you just fine. If you need any bells
and whistles..the Gs2 drives will suit your needs.

Ive installed probably 75 of them to date....all worked as advertised
nicely.

The GS-2 drives typically are used on Lathes to replace bad
vari-drives..usually Hardinge lathes. Its cheaper to install a drive
than it is to repair/replace the vari-drive..by a significant amount,
given Hardinge's rape you/dry pricing.

Gunner

"There are no leftists in mainstream American politics.

Just two right wing parties, one hard right and one softer."
Christopher A. Lee, 8/18/2013

On Mon, 19 Aug 2013 13:05:14 -0700, "Bob La Londe"
wrote:

"Karl Townsend" wrote in message
.. .
Packing line upgrade time...

My bin dump water pump is the largest noise maker in the system. I
quickly tried a VFD a couple years ago and it SQUEALED far worse than
the excess motor noise. Just as pleasant as listening to chalk squeal
on a blackboard.

Anyway, this time I want to buy a 1/2 hp VFD that doesn't have carrier
wave noise. Suggestions? BTW, the unit will be located 75' of wire
from the motor. Is a reactor needed in this case?

Karl


What is the actual source of the noise?

I run a 1/2HP VFD and 5HP VFD in the high power side cabinet on my Hurco,
and both are virtually silent. The servo dithering is louder than either
one.

Like Gunner said, and you implied, I just had bad luck last time. i
also have many VFDs with no noise. But, this is a much quiter level,
trying to get less noise than a dot matrix printer.

The problem was two years ago, maybe more. Folks on this group said it
was carrier wave and I seem to remember reactor being suggested. But
my memory sux and maybe who ever said it was full of beans.

Anyway, should i pop for a reactor? I've bought from automation direct
before with good results.

Karl

Karl Townsend fired this volley in
:

Anyway, should i pop for a reactor? I've bought from automation direct
before with good results.

If the squeal is coming from the motor itself, the reactor(s) will help
smooth the 'simulated sine wave' coming out of the inverter drive.

Good VFD's divide the stepped waveform up into small enough slices so
that the noise is of a high enough frequency not to be heard by us old
men, and not annoying to anything but cats and bats and teenagers (a good
thing).

I've used the Automation Direct VFDs and also Motortronics, with which I
have had very good experience and reliability. No noise from either
brand.

Lloyd

On Mon, 19 Aug 2013 17:18:21 -0500, Karl Townsend
wrote:

On Mon, 19 Aug 2013 13:05:14 -0700, "Bob La Londe"
wrote:

"Karl Townsend" wrote in message
. ..
Packing line upgrade time...

My bin dump water pump is the largest noise maker in the system. I
quickly tried a VFD a couple years ago and it SQUEALED far worse than
the excess motor noise. Just as pleasant as listening to chalk squeal
on a blackboard.

Anyway, this time I want to buy a 1/2 hp VFD that doesn't have carrier
wave noise. Suggestions? BTW, the unit will be located 75' of wire
from the motor. Is a reactor needed in this case?

Karl


What is the actual source of the noise?

I run a 1/2HP VFD and 5HP VFD in the high power side cabinet on my Hurco,
and both are virtually silent. The servo dithering is louder than either
one.

Like Gunner said, and you implied, I just had bad luck last time. i
also have many VFDs with no noise. But, this is a much quiter level,
trying to get less noise than a dot matrix printer.

The problem was two years ago, maybe more. Folks on this group said it
was carrier wave and I seem to remember reactor being suggested. But
my memory sux and maybe who ever said it was full of beans.

Anyway, should i pop for a reactor? I've bought from automation direct
before with good results.

Karl

you can certainly try a reactor. Though Id buy one on Ebay for much
less than a new one. Get as big a one as you can, as you may need it
down the road on some other drive...if it doesnt solve your problem.

The 1/2hp drives from AD will set you back about the price of a
reactor IRRC..they run about $140 at most.

Gunner

"There are no leftists in mainstream American politics.

Just two right wing parties, one hard right and one softer."
Christopher A. Lee, 8/18/2013

On Mon, 19 Aug 2013 18:02:08 -0500, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:

Karl Townsend fired this volley in
:

Anyway, should i pop for a reactor? I've bought from automation direct
before with good results.

If the squeal is coming from the motor itself, the reactor(s) will help
smooth the 'simulated sine wave' coming out of the inverter drive.

Good VFD's divide the stepped waveform up into small enough slices so
that the noise is of a high enough frequency not to be heard by us old
men, and not annoying to anything but cats and bats and teenagers (a good
thing).

I've used the Automation Direct VFDs and also Motortronics, with which I
have had very good experience and reliability. No noise from either
brand.

Lloyd

You hit the nail on the head about teenagers. i though it was quieter,
they threatened to mutiny.

Karl

On Mon, 19 Aug 2013 18:02:08 -0500, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:

Karl Townsend fired this volley in
:

Anyway, should i pop for a reactor? I've bought from automation direct
before with good results.

If the squeal is coming from the motor itself, the reactor(s) will help
smooth the 'simulated sine wave' coming out of the inverter drive.

Good VFD's divide the stepped waveform up into small enough slices so
that the noise is of a high enough frequency not to be heard by us old
men, and not annoying to anything but cats and bats and teenagers (a good
thing).

I've used the Automation Direct VFDs and also Motortronics, with which I
have had very good experience and reliability. No noise from either
brand.

Lloyd

The later Rockwells I've used had a menu item to change the carrier
frequency if noise was evident. Our vendor recommended reactors if
200' or more. Something to do with harmonics on the feed line. Mine
were usually about 10' or less. Mitsubishis I have now are quiet
except I can hear the cooling fans.

Good luck.

Pete Keillor

On 2013-08-20, Pete Keillor wrote:
On Mon, 19 Aug 2013 18:02:08 -0500, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:

Karl Townsend fired this volley in
m:

Anyway, should i pop for a reactor? I've bought from automation direct
before with good results.

If the squeal is coming from the motor itself, the reactor(s) will help
smooth the 'simulated sine wave' coming out of the inverter drive.

I think that the squeal is likely from loose laminations in the
stator of the motor -- and likely just right to be resonant at the
default frequency of the VFD -- so a change in frequency would likely
make a big difference. (An alternative is to force a varnish into the
laminations -- but be sure to pick one which will not attack the
varnish/enamel on the wires wound on there.) Maybe a very thin epoxy
would work.

A reactor might reduce the high frequency part getting to the
motor windings -- but is otherwise unlikely to be necessary.

A replacement motor will likely not show the same problem --
even if the same brand. But it might be the most expensive approach.

Good Luck,
DoN.

--
Remove oil spill source from e-mail
Email: | (KV4PH) Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

On Mon, 19 Aug 2013 14:15:10 -0700, Gunner Asch
wrote:

On Mon, 19 Aug 2013 14:22:08 -0500, Karl Townsend
wrote:

Packing line upgrade time...

My bin dump water pump is the largest noise maker in the system. I
quickly tried a VFD a couple years ago and it SQUEALED far worse than
the excess motor noise. Just as pleasant as listening to chalk squeal
on a blackboard.

Anyway, this time I want to buy a 1/2 hp VFD that doesn't have carrier
wave noise. Suggestions? BTW, the unit will be located 75' of wire
from the motor. Is a reactor needed in this case?

Karl

Most..not all...but most VFDs do NOT squeal. Of all the ones Ive
installed over the past 16 yrs...only one..a Hitachi 3/4hp on a drill
press squealed.

Automationdirect.com is a very good place for inexpensive drives

http://www.automationdirect.com/adc/...-Hz_Control%29

http://www.automationdirect.com/adc/...-Hz_Control%29

The GS1 drives will probably do you just fine. If you need any bells
and whistles..the Gs2 drives will suit your needs.

Ive installed probably 75 of them to date....all worked as advertised
nicely.

The GS-2 drives typically are used on Lathes to replace bad
vari-drives..usually Hardinge lathes. Its cheaper to install a drive
than it is to repair/replace the vari-drive..by a significant amount,
given Hardinge's rape you/dry pricing.

Gunner

Can you move the drive closer to the motor temporarily, just for
experimentation purposes? It's a whole lot easier to remote the
control wiring from the VFD back to where the operator is sitting.

Is the pump motor Inverter Duty rated? If you have an antique motor
out there, it could sing no matter what you do - they are made to take
60 Hz, Period, and you'll start vibrating laminations with any
inverter harmonics.

And then you make hot spots in the windings, and they start shorting
internally and provide an escape route for the Magic Smoke.

And if the pump motor's a goner, may be cheaper to replace the whole
thing. Variable Speed Pumps for swimming pools are hitting wide use -
meaning they're getting seriously cheaper. And the drives are already
integrated with the motor, and a pump body and debris strainer.

-- Bruce --

"DoN. Nichols" wrote in message
...
On 2013-08-20, Pete Keillor wrote:
On Mon, 19 Aug 2013 18:02:08 -0500, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:

Karl Townsend fired this volley in
:

Anyway, should i pop for a reactor? I've bought from automation direct
before with good results.

If the squeal is coming from the motor itself, the reactor(s) will help
smooth the 'simulated sine wave' coming out of the inverter drive.

I think that the squeal is likely from loose laminations in the
stator of the motor -- and likely just right to be resonant at the
default frequency of the VFD -- so a change in frequency would likely
make a big difference. (An alternative is to force a varnish into the
laminations -- but be sure to pick one which will not attack the
varnish/enamel on the wires wound on there.) Maybe a very thin epoxy
would work.

A reactor might reduce the high frequency part getting to the
motor windings -- but is otherwise unlikely to be necessary.

A replacement motor will likely not show the same problem --
even if the same brand. But it might be the most expensive approach.


My impression has always been that the PWM frequency was simply too low on
first-generation inverters; and that while anything built within the past
couple decades might well still create some annoyong electrical noise,
acoustic emmissions will be at a frequency substantionally above the human
hearing threshold

"PrecisionmachinisT" wrote in message
...

"DoN. Nichols" wrote in message
...
On 2013-08-20, Pete Keillor wrote:
On Mon, 19 Aug 2013 18:02:08 -0500, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:

Karl Townsend fired this volley in
m:

Anyway, should i pop for a reactor? I've bought from automation direct
before with good results.

If the squeal is coming from the motor itself, the reactor(s) will help
smooth the 'simulated sine wave' coming out of the inverter drive.

I think that the squeal is likely from loose laminations in the
stator of the motor -- and likely just right to be resonant at the
default frequency of the VFD -- so a change in frequency would likely
make a big difference. (An alternative is to force a varnish into the
laminations -- but be sure to pick one which will not attack the
varnish/enamel on the wires wound on there.) Maybe a very thin epoxy
would work.

A reactor might reduce the high frequency part getting to the
motor windings -- but is otherwise unlikely to be necessary.

A replacement motor will likely not show the same problem --
even if the same brand. But it might be the most expensive approach.


My impression has always been that the PWM frequency was simply too low on
first-generation inverters; and that while anything built within the past
couple decades might well still create some annoyong electrical noise,
acoustic emmissions will be at a frequency substantionally above the human
hearing threshold

I don' know what the total range of human hearing is, but when I was younger
I could hear or be aware of frequencies upto about 20kz. Depending on the
sound generator somewhere between 19.5 and 20.5 I would notice it go
substantially silent. Now as I have gotten older I have noticed that I
can't hear much above about 17.5.

Anyway, the range of human varies with age, and does so noticeably with men
in the high frequency range. Also, its possible that some people have a
wider range of hearing atleast at the peak level of their physical
development. All of that being said, who knows what odd frequencies can be
generated by a VFD.

Hmmmm... I'm not sure any of that makes a point, but its some nice anecdotal
information to consider. LOL.

On Wed, 21 Aug 2013 09:27:40 -0700, "Bob La Londe"
wrote:

"PrecisionmachinisT" wrote in message
...

"DoN. Nichols" wrote in message
...
On 2013-08-20, Pete Keillor wrote:
On Mon, 19 Aug 2013 18:02:08 -0500, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:

Karl Townsend fired this volley in
om:

Anyway, should i pop for a reactor? I've bought from automation direct
before with good results.

If the squeal is coming from the motor itself, the reactor(s) will help
smooth the 'simulated sine wave' coming out of the inverter drive.

I think that the squeal is likely from loose laminations in the
stator of the motor -- and likely just right to be resonant at the
default frequency of the VFD -- so a change in frequency would likely
make a big difference. (An alternative is to force a varnish into the
laminations -- but be sure to pick one which will not attack the
varnish/enamel on the wires wound on there.) Maybe a very thin epoxy
would work.

A reactor might reduce the high frequency part getting to the
motor windings -- but is otherwise unlikely to be necessary.

A replacement motor will likely not show the same problem --
even if the same brand. But it might be the most expensive approach.


My impression has always been that the PWM frequency was simply too low on
first-generation inverters; and that while anything built within the past
couple decades might well still create some annoyong electrical noise,
acoustic emmissions will be at a frequency substantionally above the human
hearing threshold

I don' know what the total range of human hearing is, but when I was younger
I could hear or be aware of frequencies upto about 20kz. Depending on the
sound generator somewhere between 19.5 and 20.5 I would notice it go
substantially silent. Now as I have gotten older I have noticed that I
can't hear much above about 17.5.

Anyway, the range of human varies with age, and does so noticeably with men
in the high frequency range. Also, its possible that some people have a
wider range of hearing atleast at the peak level of their physical
development. All of that being said, who knows what odd frequencies can be
generated by a VFD.

Hmmmm... I'm not sure any of that makes a point, but its some nice anecdotal
information to consider. LOL.


Female voices are predominately high frequency.

Men, as we age, tend to lose our hearing at high frequencies first.

Coincidence?

"Bob La Londe" fired this volley in
:

Hmmmm... I'm not sure any of that makes a point, but its some nice
anecdotal information to consider. LOL.

Bob,
I used not to be comfortable in a room with a TV which had a loose
bracket on the flyback transformer. The 17.5KHz deflection frequency
literally drove me out of the room!

At 64, I can't hear much above 10KHz, and suspect that's diminishing due
to my fireworks and explosives activities (and Viet Nam, where I had an
eardrum perforated by a nearby and unexpected firing of a Browning .50).

Lloyd

On Wed, 21 Aug 2013 13:44:08 -0400, Spehro Pefhany
wrote:

On Wed, 21 Aug 2013 09:27:40 -0700, "Bob La Londe"
wrote:

"PrecisionmachinisT" wrote in message
...

"DoN. Nichols" wrote in message
...
On 2013-08-20, Pete Keillor wrote:
On Mon, 19 Aug 2013 18:02:08 -0500, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:

Karl Townsend fired this volley in
news:j465191dquf4r4bm749ff44husbamrap90@4ax. com:

Anyway, should i pop for a reactor? I've bought from automation direct
before with good results.

If the squeal is coming from the motor itself, the reactor(s) will help
smooth the 'simulated sine wave' coming out of the inverter drive.

I think that the squeal is likely from loose laminations in the
stator of the motor -- and likely just right to be resonant at the
default frequency of the VFD -- so a change in frequency would likely
make a big difference. (An alternative is to force a varnish into the
laminations -- but be sure to pick one which will not attack the
varnish/enamel on the wires wound on there.) Maybe a very thin epoxy
would work.

A reactor might reduce the high frequency part getting to the
motor windings -- but is otherwise unlikely to be necessary.

A replacement motor will likely not show the same problem --
even if the same brand. But it might be the most expensive approach.


My impression has always been that the PWM frequency was simply too low on
first-generation inverters; and that while anything built within the past
couple decades might well still create some annoyong electrical noise,
acoustic emmissions will be at a frequency substantionally above the human
hearing threshold

I don' know what the total range of human hearing is, but when I was younger
I could hear or be aware of frequencies upto about 20kz. Depending on the
sound generator somewhere between 19.5 and 20.5 I would notice it go
substantially silent. Now as I have gotten older I have noticed that I
can't hear much above about 17.5.

Anyway, the range of human varies with age, and does so noticeably with men
in the high frequency range. Also, its possible that some people have a
wider range of hearing atleast at the peak level of their physical
development. All of that being said, who knows what odd frequencies can be
generated by a VFD.

Hmmmm... I'm not sure any of that makes a point, but its some nice anecdotal
information to consider. LOL.


Female voices are predominately high frequency.

Men, as we age, tend to lose our hearing at high frequencies first.

Coincidence?

Survival.


"There are no leftists in mainstream American politics.

Just two right wing parties, one hard right and one softer."
Christopher A. Lee, 8/18/2013

On Wed, 21 Aug 2013 12:59:55 -0500, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:

"Bob La Londe" fired this volley in
:

Hmmmm... I'm not sure any of that makes a point, but its some nice
anecdotal information to consider. LOL.

Bob,
I used not to be comfortable in a room with a TV which had a loose
bracket on the flyback transformer. The 17.5KHz deflection frequency
literally drove me out of the room!

At 64, I can't hear much above 10KHz, and suspect that's diminishing due
to my fireworks and explosives activities (and Viet Nam, where I had an
eardrum perforated by a nearby and unexpected firing of a Browning .50).

Lloyd

Try having a claymore go off over your hide. Takes out both eardrums.
Trust me.


"There are no leftists in mainstream American politics.

Just two right wing parties, one hard right and one softer."
Christopher A. Lee, 8/18/2013

Gunner Asch fired this volley in
:

Try having a claymore go off over your hide. Takes out both eardrums.
Trust me.


I've been within 20M of them on the (so-called) 'safe side'. Yeah, they're
loud, even when you're hunkered-down below the projectile path.

Lloyd

On Wed, 21 Aug 2013 14:04:31 -0500, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:

Gunner Asch fired this volley in
:

Try having a claymore go off over your hide. Takes out both eardrums.
Trust me.


I've been within 20M of them on the (so-called) 'safe side'. Yeah, they're
loud, even when you're hunkered-down below the projectile path.

Lloyd

Im fortunate I can still hear..mostly. I have however gotten pretty
good at lip reading most women. I can hear their voices..I just cant
make out what many say. Way above my hearing range.

I had my hearing checked by a pro a few years ago..and he had the
chart with my hearing range in his hand..he looked up at me...looked
at the chart..and said..let me guess..combat vet right?

The chart had holes in the hearing ranges all over the place. He said
only combat vets have a chart that looks like it was hit with a
shotgun a couple times..with scattered holes all over it.
Its been years since Ive heard a violin.

Shrug.


"There are no leftists in mainstream American politics.

Just two right wing parties, one hard right and one softer."
Christopher A. Lee, 8/18/2013

One could get some dope or varnish and drip into the area
and re-coat the fins into a firm position. Might be an insulation
sheet that is hard with varnish - shaking and making noise.

Martin

On 8/21/2013 1:39 AM, PrecisionmachinisT wrote:
"DoN. Nichols" wrote in message
...
On 2013-08-20, Pete Keillor wrote:
On Mon, 19 Aug 2013 18:02:08 -0500, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:

Karl Townsend fired this volley in
:

Anyway, should i pop for a reactor? I've bought from automation direct
before with good results.

If the squeal is coming from the motor itself, the reactor(s) will help
smooth the 'simulated sine wave' coming out of the inverter drive.

I think that the squeal is likely from loose laminations in the
stator of the motor -- and likely just right to be resonant at the
default frequency of the VFD -- so a change in frequency would likely
make a big difference. (An alternative is to force a varnish into the
laminations -- but be sure to pick one which will not attack the
varnish/enamel on the wires wound on there.) Maybe a very thin epoxy
would work.

A reactor might reduce the high frequency part getting to the
motor windings -- but is otherwise unlikely to be necessary.

A replacement motor will likely not show the same problem --
even if the same brand. But it might be the most expensive approach.


My impression has always been that the PWM frequency was simply too low on
first-generation inverters; and that while anything built within the past
couple decades might well still create some annoyong electrical noise,
acoustic emmissions will be at a frequency substantionally above the human
hearing threshold

Remember that there are sub harmonics being generated as well.
Martin

On 8/21/2013 11:27 AM, Bob La Londe wrote:
"PrecisionmachinisT" wrote in
message ...

"DoN. Nichols" wrote in message
...
On 2013-08-20, Pete Keillor wrote:
On Mon, 19 Aug 2013 18:02:08 -0500, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:

Karl Townsend fired this volley in
:

Anyway, should i pop for a reactor? I've bought from automation
direct
before with good results.

If the squeal is coming from the motor itself, the reactor(s) will
help
smooth the 'simulated sine wave' coming out of the inverter drive.

I think that the squeal is likely from loose laminations in the
stator of the motor -- and likely just right to be resonant at the
default frequency of the VFD -- so a change in frequency would likely
make a big difference. (An alternative is to force a varnish into the
laminations -- but be sure to pick one which will not attack the
varnish/enamel on the wires wound on there.) Maybe a very thin epoxy
would work.

A reactor might reduce the high frequency part getting to the
motor windings -- but is otherwise unlikely to be necessary.

A replacement motor will likely not show the same problem --
even if the same brand. But it might be the most expensive approach.


My impression has always been that the PWM frequency was simply too
low on first-generation inverters; and that while anything built
within the past couple decades might well still create some annoyong
electrical noise, acoustic emmissions will be at a frequency
substantionally above the human hearing threshold

I don' know what the total range of human hearing is, but when I was
younger I could hear or be aware of frequencies upto about 20kz.
Depending on the sound generator somewhere between 19.5 and 20.5 I would
notice it go substantially silent. Now as I have gotten older I have
noticed that I can't hear much above about 17.5.

Anyway, the range of human varies with age, and does so noticeably with
men in the high frequency range. Also, its possible that some people
have a wider range of hearing atleast at the peak level of their
physical development. All of that being said, who knows what odd
frequencies can be generated by a VFD.

Hmmmm... I'm not sure any of that makes a point, but its some nice
anecdotal information to consider. LOL.

Martin Eastburn fired this volley in
:

One could get some dope or varnish and drip into the area
and re-coat the fins into a firm position.

They weren't 'coated' to begin with... they were vacuum-varnished.

Knowlegeable and judicial 'wedging' is the way the noises are settled in
a real motor shop/lab. Occasionally, you'll see an entire frame go back
into the vacuum pot.

Lloyd

"Lloyd E. Sponenburgh" wrote:

"Bob La Londe" fired this volley in
:

Hmmmm... I'm not sure any of that makes a point, but its some nice
anecdotal information to consider. LOL.

Bob,
I used not to be comfortable in a room with a TV which had a loose
bracket on the flyback transformer. The 17.5KHz deflection frequency
literally drove me out of the room!


15,734.34 Hz for color, 15,750 Hz for B&W. The reason for the
difference is to eliminate a color beat, but allow existing TVs to see
color broadcasts.


--
Anyone wanting to run for any political office in the US should have to
have a DD214, and a honorable discharge.

"Michael A. Terrell" fired this volley in
m:

15,734.34 Hz for color, 15,750 Hz for B&W. The reason for the
difference is to eliminate a color beat, but allow existing TVs to see
color broadcasts.

yep, flipped a couple of digits.

And... it was back in the BW days, when I was young enough to hear that
frequency.

We didn't have color TV until about three years after I got married!
(don't say it... no, I didn't know Marconi, except by reputation!)
Lloyd

"Michael A. Terrell" on Thu, 22 Aug 2013
12:06:15 -0400 typed in rec.crafts.metalworking the following:
"Lloyd E. Sponenburgh" wrote:
"Bob La Londe" fired:
Hmmmm... I'm not sure any of that makes a point, but its some nice
anecdotal information to consider. LOL.
Bob,
I used not to be comfortable in a room with a TV which had a loose
bracket on the flyback transformer. The 17.5KHz deflection frequency
literally drove me out of the room!
15,734.34 Hz for color, 15,750 Hz for B&W. The reason for the
difference is to eliminate a color beat, but allow existing TVs to see
color broadcasts.

Some people are more "perceptive" than others. The effect of
fluorescent light bulbs for some folks is not "illumination" but
"disco strobe light" - which makes concentrating in school or at work
"difficult".

Tangent question - AM radio reception in a pickup truck. ('98
Mazda, EFI, manual 244000 miles)

I leave 'near' Everett WA, twenty miles as the seagull flies from
Paine Field (a bit farther if the seagull is driving and stuck in
traffic.) I cannot believe that I live so far out in the boonies,
that I can't pick up local radio stations. (At night - the two
strongest stations are in Calgary and Vancouver BC. Kind of tough to
figure the local weather from their reports - in Celsius, no less. But
I digress.)
Regardless, and I realize diagnosing electrical troubles by mail
is right up there with getting financial advice on the radio and other
forms of occult prognostication, I have noticed a couple things. I
get over the ridge - and past the high-tension power lines - and I can
generally get the Seattle Stations. But sometimes, especially when I
tune to ~550 AM, I get a "sound" - sort of like a marlin Brando
clearing his throat on sideband. a sort of 'pop' - gargle, 'pop' -
gargle, 'pop' - gargle,'pop' - gargle', pop' - gargle.
It isn't (as far as I can tell) related to engine speed - in fact
I can shut off the engine, energize the circuit and the radio is
clear, then pop the clutch, resume engine running - and no pop-gargle.
Also, on occasion I have "joggled" the key - returning it back to the
proper detent for "engine is running", not part way to "engage starter
solenoid!" - it has cleared up. For a while.

Now with that collection of wonderfully accurate set of technical
descriptions, no doubt you can channel the mighty psychic powers of
the Late Great Carnac and know exactly what is the source of my woes.
(Aside from the County PUD.) And what the solution is, aside from
"Plug the ipod in and listen to that instead."

thanks in advance.

pyotr

--
pyotr filipivich
"With Age comes Wisdom. Although more often, Age travels alone."

On Thu, 22 Aug 2013 11:10:05 -0700, pyotr filipivich
wrote:

"Michael A. Terrell" on Thu, 22 Aug 2013
12:06:15 -0400 typed in rec.crafts.metalworking the following:
"Lloyd E. Sponenburgh" wrote:
"Bob La Londe" fired:
Hmmmm... I'm not sure any of that makes a point, but its some nice
anecdotal information to consider. LOL.
Bob,
I used not to be comfortable in a room with a TV which had a loose
bracket on the flyback transformer. The 17.5KHz deflection frequency
literally drove me out of the room!
15,734.34 Hz for color, 15,750 Hz for B&W. The reason for the
difference is to eliminate a color beat, but allow existing TVs to see
color broadcasts.

Some people are more "perceptive" than others. The effect of
fluorescent light bulbs for some folks is not "illumination" but
"disco strobe light" - which makes concentrating in school or at work
"difficult".

Tangent question - AM radio reception in a pickup truck. ('98
Mazda, EFI, manual 244000 miles)

I leave 'near' Everett WA, twenty miles as the seagull flies from
Paine Field (a bit farther if the seagull is driving and stuck in
traffic.) I cannot believe that I live so far out in the boonies,
that I can't pick up local radio stations. (At night - the two
strongest stations are in Calgary and Vancouver BC. Kind of tough to
figure the local weather from their reports - in Celsius, no less. But
I digress.)
Regardless, and I realize diagnosing electrical troubles by mail
is right up there with getting financial advice on the radio and other
forms of occult prognostication, I have noticed a couple things. I
get over the ridge - and past the high-tension power lines - and I can
generally get the Seattle Stations. But sometimes, especially when I
tune to ~550 AM, I get a "sound" - sort of like a marlin Brando
clearing his throat on sideband. a sort of 'pop' - gargle, 'pop' -
gargle, 'pop' - gargle,'pop' - gargle', pop' - gargle.
It isn't (as far as I can tell) related to engine speed - in fact
I can shut off the engine, energize the circuit and the radio is
clear, then pop the clutch, resume engine running - and no pop-gargle.
Also, on occasion I have "joggled" the key - returning it back to the
proper detent for "engine is running", not part way to "engage starter
solenoid!" - it has cleared up. For a while.

Now with that collection of wonderfully accurate set of technical
descriptions, no doubt you can channel the mighty psychic powers of
the Late Great Carnac and know exactly what is the source of my woes.
(Aside from the County PUD.) And what the solution is, aside from
"Plug the ipod in and listen to that instead."

thanks in advance.

pyotr

--
pyotr filipivich
"With Age comes Wisdom. Although more often, Age travels alone."
Try removing your instrument fuse - see if it goes away. Don't know
what kind of instrument regulator they are using theses days, byt they
used to use a thermal unit that could (and often did) make terrible
noise on AM radio. I replaced quite a few with solid state regulators
over the years. (no, the dash instruments do NOT work on 12 volts) If
the BZZ POP BZZ POP goes away with the instrument (not instrument
lighting) fuse pulled, you know where to look.

On 2013-08-21, Bob La Londe wrote:
"PrecisionmachinisT" wrote in message
...

"DoN. Nichols" wrote in message
...
On 2013-08-20, Pete Keillor wrote:
On Mon, 19 Aug 2013 18:02:08 -0500, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:

[ ... ]

If the squeal is coming from the motor itself, the reactor(s) will help
smooth the 'simulated sine wave' coming out of the inverter drive.

I think that the squeal is likely from loose laminations in the
stator of the motor -- and likely just right to be resonant at the
default frequency of the VFD -- so a change in frequency would likely
make a big difference.

[ ... ]

A replacement motor will likely not show the same problem --
even if the same brand. But it might be the most expensive approach.


My impression has always been that the PWM frequency was simply too low on
first-generation inverters; and that while anything built within the past
couple decades might well still create some annoyong electrical noise,
acoustic emmissions will be at a frequency substantionally above the human
hearing threshold

I don' know what the total range of human hearing is, but when I was younger
I could hear or be aware of frequencies upto about 20kz.

Well ... the usual figure given is 20 Hz to 20 KHz.

Depending on the
sound generator somewhere between 19.5 and 20.5 I would notice it go
substantially silent. Now as I have gotten older I have noticed that I
can't hear much above about 17.5.

I have had poor high-frequency hearing at least since it was
discovered in high school. In particular, things pretty much drop off
about 2.6 KHz -- though I remember playing with headphones and a signal
generator and discovering that I could hear a little just above 20 KHz,
though I don't know whether the system was generating sub-harmonics.

I did a lot of things at a kid which could have damaged my
hearing.

But I also remember, shortly after the high-frequency loss was
discovered, sitting in my room with a pair of Koss Pro-4A headphones
(pretty good sealing around the ear), and with a frequency sweep test
record (LP for those who remember older technology). As the frequency
was increasing, I was turning up the gain to try to keep hearing it. A
friend, sitting about 10 feet away, screamed "How can you stand it!"
about the time I was losing it totally.

Anyway, the range of human varies with age, and does so noticeably with men
in the high frequency range.

While I am a man, I don't think that I am in the "high frequency
range" in any sense -- but my hearing in the high frequency range was
lost quite early, as I mentioned above. :-)

Also, its possible that some people have a
wider range of hearing atleast at the peak level of their physical
development. All of that being said, who knows what odd frequencies can be
generated by a VFD.

The makers know the range of the clock frequencies. Whether
they will be *audible* depends on whatever they are driving, because
there is nothing in the VFD itself capable of acting as a transducer
from electrical signals to audio signals.

The *motor*, however, can quite easily do this, depending on how
well it is made. The stator is made of a stack of laminations of a thin
metal selected for its magnetic properties, which forms a number of
poles around which is wound many turns of enameled wire. As the current
increases, it generates a magnetic field. If there is a gap between any
two of the laminations, it will attract the two pieces together closing
the gap, and making a "tick" as they touch. When the current (and
field) decrease (this is AC after all), they separate again, and are set
for the next cycle. A really loose lamination could cause a buzz at
normal line frequency. That does not carry very far. But if the VFD is
running at a mid audio frequency -- say 400 Hz up to 12,000 Hz, you will
get a quite audible sound.

And it is possible that the free length of the lamination might
be just right to resonate at or near the frequency of the VFD -- which
is why shifting the frequency can make a big difference.

The wires can move too -- but usually the proportion of current
required and the short lengths and heavy gauge of the wire means that
they will not move enough to generate significant sound in the typical
motor.

Power transformers (once commonly used in electronic equipment)
have the same construction as the motor stators, but typically a wooden
wedge used to be driven in between the coil and the center pole of the
laminations, thus minimizing the freedom to vibrate. (Really good ones
in the early days were put in a metal can and the can was then filled
with melted tar, so no chance of lamination vibration there. But later
and cheaper ones have produced enough noise at 60 Hz so I could hear
them.

*Most* motors are well enough made (stator dipped in a coating
which hardens, both to hold the windings in place, and to keep the
laminations together).

Hmmmm... I'm not sure any of that makes a point, but its some nice anecdotal
information to consider. LOL.

And a bit more information added, showing how a motor can
generate sound -- and why it is more audible with a VFD than with the
power company's 60 Hz (or 50 Hz in the UK).

Enjoy,
DoN.

--
Remove oil spill source from e-mail
Email: | (KV4PH) Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

on Thu, 22 Aug 2013 16:21:00 -0400 typed in
rec.crafts.metalworking the following:

thanks in advance.

pyotr

--
pyotr filipivich
"With Age comes Wisdom. Although more often, Age travels alone."
Try removing your instrument fuse - see if it goes away. Don't know
what kind of instrument regulator they are using theses days, byt they
used to use a thermal unit that could (and often did) make terrible
noise on AM radio. I replaced quite a few with solid state regulators
over the years. (no, the dash instruments do NOT work on 12 volts) If
the BZZ POP BZZ POP goes away with the instrument (not instrument
lighting) fuse pulled, you know where to look.

Thanks, an option to follow up on.
--
pyotr filipivich
"With Age comes Wisdom. Although more often, Age travels alone."