L
Look165
Guest
I heard from many girls that size doesn't matter !! LOL
DaveC a ĂŠcrit :
DaveC a ĂŠcrit :
L
legg
Guest
On Sun, 13 Mar 2016 15:34:07 -0000, MJC <gravity@mjcoon.plus.com>
wrote:
www.lanl.gov/thermoacoustics/Pubs/
RL
wrote:
www.lanl.gov/thermoacoustics/Pubs/
RL
N
N_Cook
Guest
On 13/03/2016 16:22, Don Bruder wrote:
Wasn't there some scheme to generate sound for large area advertising by
using aurora? presumably someone realised polar bears don't buy much stuff.
Wasn't there some scheme to generate sound for large area advertising by
using aurora? presumably someone realised polar bears don't buy much stuff.
M
MJC
Guest
In article <5aae6e94-41fc-4a9a-832b-e165deb33e98@googlegroups.com>,
jurb6006@gmail.com says...
That recalls some old saw about whether anything is real if not
observed. I think sound has been reproduced even if no-one hears.
As to moving air counting as a "part"... In space no-one can hear
spurious arguments!
Mike.
jurb6006@gmail.com says...
That recalls some old saw about whether anything is real if not
observed. I think sound has been reproduced even if no-one hears.
As to moving air counting as a "part"... In space no-one can hear
spurious arguments!
Mike.
C
Chris Jones
Guest
On 14/03/2016 02:34, MJC wrote:
http://www.roger-russell.com/ionovac/ionovac.htm#ionofane
http://www.ebay.com/itm/171837115818
http://www.roger-russell.com/ionovac/ionovac.htm#ionofane
http://www.ebay.com/itm/171837115818
P
pfjw@aol.com
Guest
On Saturday, March 12, 2016 at 11:16:48 AM UTC-5, DaveC wrote:
THE *MOTOR PULLEY* DIAMETER..... Not the pinch roller.
Peter Wieck
Melrose Park, PA
THE *MOTOR PULLEY* DIAMETER..... Not the pinch roller.
Peter Wieck
Melrose Park, PA
P
pfjw@aol.com
Guest
On Monday, March 14, 2016 at 12:28:26 PM UTC-4, legg wrote:
Um... A flywheel is a momentum device attached to a system to provide smoothing. Many (very much most) DC motors are pulse driven. The flywheel removes these pulses. Tape speed is determined by the capstan motor pulley diameter. FULL STOP.
Peter Wieck
Melrose Park, PA
Um... A flywheel is a momentum device attached to a system to provide smoothing. Many (very much most) DC motors are pulse driven. The flywheel removes these pulses. Tape speed is determined by the capstan motor pulley diameter. FULL STOP.
Peter Wieck
Melrose Park, PA
N
N_Cook
Guest
On 14/03/2016 17:27, legg wrote:
That would be lead to a much closer pair of pulley diameters.
But then although you have a free range of pulley sizes, as cast and
machined, the sintered metal bearings come in only discrete sizes of * x
0.1mm , so you have to increase/decrease the pulley diameter ratio to
then be compatible to 2 available bearing diameters and hence spindle
diameters.
That is the reason i'd go for
That would be lead to a much closer pair of pulley diameters.
But then although you have a free range of pulley sizes, as cast and
machined, the sintered metal bearings come in only discrete sizes of * x
0.1mm , so you have to increase/decrease the pulley diameter ratio to
then be compatible to 2 available bearing diameters and hence spindle
diameters.
That is the reason i'd go for
L
legg
Guest
On Mon, 14 Mar 2016 07:04:19 -0700 (PDT), "pfjw@aol.com"
<pfjw@aol.com> wrote:
Question was re flywheel diameter differences. Motor pulley drives
both. Same belt on two different dia flywheels, yet obtains same
spindle rotation at their separate pinch rollers.
Identical belt speed should drive a smaller dia flywheel faster. Motor
speed does not account for this physical difference, as it is uniform
for both functions.
Supposition is that the difference in flywheel dia is related to belt
thickness, as one flywheel is inside, and other is outside the drive
belt loop.
RL
<pfjw@aol.com> wrote:
Question was re flywheel diameter differences. Motor pulley drives
both. Same belt on two different dia flywheels, yet obtains same
spindle rotation at their separate pinch rollers.
Identical belt speed should drive a smaller dia flywheel faster. Motor
speed does not account for this physical difference, as it is uniform
for both functions.
Supposition is that the difference in flywheel dia is related to belt
thickness, as one flywheel is inside, and other is outside the drive
belt loop.
RL
D
DaveC
Guest
On 14 Mar 2016, N_Cook wrote
(in article <nc6p5h$3hp$1@dont-email.me>
:
I (op) have accepted the theory that difference is to avoid additive
resonance of the capstan shafts in bronze(?)--not ball--bearings. Difference
flywheel sizes plus different capstan shaftssizes (2mm and 2.1mm) results in
same tape speed (in opposite directions--this is an auto-reverse mechanism)
and different resonances.
(in article <nc6p5h$3hp$1@dont-email.me>
:I (op) have accepted the theory that difference is to avoid additive
resonance of the capstan shafts in bronze(?)--not ball--bearings. Difference
flywheel sizes plus different capstan shaftssizes (2mm and 2.1mm) results in
same tape speed (in opposite directions--this is an auto-reverse mechanism)
and different resonances.
L
legg
Guest
On Mon, 14 Mar 2016 11:41:28 -0700 (PDT), "pfjw@aol.com"
<pfjw@aol.com> wrote:
In these machines a single motor with a pulley on its shaft, drives
the outer rims of the two differently sized flywheels, through a
single belt.
I've measured the spindles at the pinch rollers and they are a
different diameter, as was suggested by DaveC, so belt thickness isn't
responsible for compensation of the flywheel sizes - the spindles are
scaled with the flywheel diameter.
Never occurred to me to wonder about this, before, or to check it out.
Happy just to keep them going.
RL
<pfjw@aol.com> wrote:
In these machines a single motor with a pulley on its shaft, drives
the outer rims of the two differently sized flywheels, through a
single belt.
I've measured the spindles at the pinch rollers and they are a
different diameter, as was suggested by DaveC, so belt thickness isn't
responsible for compensation of the flywheel sizes - the spindles are
scaled with the flywheel diameter.
Never occurred to me to wonder about this, before, or to check it out.
Happy just to keep them going.
RL
P
Phil Allison
Guest
N_Cook wrote:
** The supposition is nonsense.
Where the drive belt is curved, the outside radius is greater - but both flywheels are on the INSIDE of curves.
..... Phil
** The supposition is nonsense.
Where the drive belt is curved, the outside radius is greater - but both flywheels are on the INSIDE of curves.
..... Phil
Guest
to the op..
only one pinch roller is engaged at a time, depending upon which direction the tape is traveling?
so the two flywheels turn in opposite directions?
How do they get the second flywheel to spin in the opposite direction?
Maybe that has something to do with the need for a different size?
M
only one pinch roller is engaged at a time, depending upon which direction the tape is traveling?
so the two flywheels turn in opposite directions?
How do they get the second flywheel to spin in the opposite direction?
Maybe that has something to do with the need for a different size?
M
P
pfjw@aol.com
Guest
On Tuesday, March 15, 2016 at 9:29:42 AM UTC-4, mako...@yahoo.com wrote:
> Maybe that has something to do with the need for a different size?
Mpfffff... Let's get down to it.
The most likely reason the two similar-function parts are of a different size is that the physical parameters of the entirety suggested/led to this decision. As neither have *one damned thing* to do with the actual tape speed, the reasons may be no more complex than that.
Peter Wieck
Melrose Park, PA
> Maybe that has something to do with the need for a different size?
Mpfffff... Let's get down to it.
The most likely reason the two similar-function parts are of a different size is that the physical parameters of the entirety suggested/led to this decision. As neither have *one damned thing* to do with the actual tape speed, the reasons may be no more complex than that.
Peter Wieck
Melrose Park, PA
P
Phil Allison
Guest
mako...@yahoo.com wrote:
** Look at the diagram - the belt goes most of the way around the larger flywheel ( 153 ) but only a small part of the way around the smaller one ( 152).
IOW it fits where the "151" is shown, where the belt is curved the opposite way.
..... Phil
** Look at the diagram - the belt goes most of the way around the larger flywheel ( 153 ) but only a small part of the way around the smaller one ( 152).
IOW it fits where the "151" is shown, where the belt is curved the opposite way.
..... Phil
D
DaveC
Guest
Yes
> so the two flywheels turn in opposite directions?
Yes
> How do they get the second flywheel to spin in the opposite direction?
look at the diagram (in the original post). The Belt goes around the 2
flywheels such that the belts are driven in opposite directions.
Flywheels are differentdiameters AND capstan spindles (pressed into the
center of the flywheels) are different diameters. The flywheel/spindle
diameters are calculated such that the resulting tape speed is the same for
both, only in opposite directions (one for Side A, one for Side B).
The reason for the differences, it seems, is to help avoid (or minimize)
resonant frequency set up by the spindles turning in their bearings.
Different diameters/speeds = lower resonance.
(op)
Guest
So let me get this straight. The consensus now is that it has nothing to do with the thickness of the belt but is to avoid resonance, Logically resulting in less wow and flutter I would assume.
Interesting. I remember the old Walkmans that had two flywheels going in opposite directions, not for autoreverse, but so that when the unit was moved, turned whatever, it would maintain the speed. But in that case of course the two flywheels were the same weight and diameter so the angular forces would cancel out.
Really, on the surface is seemed that the thickness of the belt was the reason for this but that has been eliminated. Would be nice to look at a few other models and see how they are put together. Ha, there is only one autoreverse deck on the property and it doesn't belong to me. That'll learn me to throw shit out.
Interesting. I remember the old Walkmans that had two flywheels going in opposite directions, not for autoreverse, but so that when the unit was moved, turned whatever, it would maintain the speed. But in that case of course the two flywheels were the same weight and diameter so the angular forces would cancel out.
Really, on the surface is seemed that the thickness of the belt was the reason for this but that has been eliminated. Would be nice to look at a few other models and see how they are put together. Ha, there is only one autoreverse deck on the property and it doesn't belong to me. That'll learn me to throw shit out.
P
Phil Allison
Guest
jurb...@gmail.com wrote:
** The OP also posted his Q on sci.electronics.design and in my first reply there I pointed out the possible resonance issue as the reason for differing flywheel diameters.
A rubber belt and flywheel system has a resonant frequency - resulting from the springiness of the belt and the inertia of the wheel. I figured that where two flywheels are coupled by the same belt, it is better if their inertias are non identical so the resonant frequencies differ and so do not reinforce.
** A really dopey idea based on a fallacy.
..... Phil
** The OP also posted his Q on sci.electronics.design and in my first reply there I pointed out the possible resonance issue as the reason for differing flywheel diameters.
A rubber belt and flywheel system has a resonant frequency - resulting from the springiness of the belt and the inertia of the wheel. I figured that where two flywheels are coupled by the same belt, it is better if their inertias are non identical so the resonant frequencies differ and so do not reinforce.
** A really dopey idea based on a fallacy.
..... Phil
M
Michael A. Terrell
Guest
jurb6006@gmail.com wrote:
Only two students in my school system got every question right on
that part of the aptitude tests. Myself, and a girl who like to work on
cars. I also got the top scores in math and science. I only got a 90 for
English. I took every math, science and shop class that they could fit
into my schedule, each year. Several years later I tested out of an
Electronics Engineering school while serving in the U.S. Army. I've
worked with very intelligent people who only finished high school, and
I've had the misfortune of working with those who can pass tests but who
are so @#$%^&* stupid that they set the shop on fire with a soldering
iron.
Only two students in my school system got every question right on
that part of the aptitude tests. Myself, and a girl who like to work on
cars. I also got the top scores in math and science. I only got a 90 for
English. I took every math, science and shop class that they could fit
into my schedule, each year. Several years later I tested out of an
Electronics Engineering school while serving in the U.S. Army. I've
worked with very intelligent people who only finished high school, and
I've had the misfortune of working with those who can pass tests but who
are so @#$%^&* stupid that they set the shop on fire with a soldering
iron.
Guest
Michael Terrell wrote: " Only two students in my school system got every question right on
that part of the aptitude tests. Myself, and a girl who like to work on
cars. I also got the top scores in math and science. I only got a 90 for
English. I took every math, science and shop class that they could fit
into my schedule, each year. Several years later I tested out of an "
I envy people like you - seriously! It shows
how influences(chemical and otherwise) during
and after conception, and after birth and during
childhood - chemical and otherwise - can have
an effect on a child and later an adult.
"Only got a 90 for english"??? I was lucky to
get 90s in THAT - and 60s to 70s in all my other
subjects. Math? They had to make up a grade
just so I wouldn't have trouble later on getting
in to college. My single biggest regret in LIFE -
not being able to even read numbers, let alone
add, subtract, multiply, or do anything Greek
with them(!) And I trace it all back to some
activities my expectant folks were engaged in
back in the late '60s, and some choice names
my Dad coined me post-toddler-hood.
that part of the aptitude tests. Myself, and a girl who like to work on
cars. I also got the top scores in math and science. I only got a 90 for
English. I took every math, science and shop class that they could fit
into my schedule, each year. Several years later I tested out of an "
I envy people like you - seriously! It shows
how influences(chemical and otherwise) during
and after conception, and after birth and during
childhood - chemical and otherwise - can have
an effect on a child and later an adult.
"Only got a 90 for english"??? I was lucky to
get 90s in THAT - and 60s to 70s in all my other
subjects. Math? They had to make up a grade
just so I wouldn't have trouble later on getting
in to college. My single biggest regret in LIFE -
not being able to even read numbers, let alone
add, subtract, multiply, or do anything Greek
with them(!) And I trace it all back to some
activities my expectant folks were engaged in
back in the late '60s, and some choice names
my Dad coined me post-toddler-hood.