I have an aerolatte milk frother that is just about OK to make cappuccino style foam when the batteries are new. So having returned an espresso maker due to the feebleness of the steam outlet, I went back to the aerolatte frother, and tried it on 4.5v and 6v in place of the usual 3volts.
This improved it dramatically, but how do I know what is too much stress on the motor ?
I suppose it is related to how much the motor is slowed down in the milk, in which case what is the best way to measure the rotation speed ?
Simon.

On 29/11/17 19:08, sm_jamieson wrote:
I have an aerolatte milk frother that is just about OK to make cappuccino style foam when the batteries are new. So having returned an espresso maker due to the feebleness of the steam outlet, I went back to the aerolatte frother, and tried it on 4.5v and 6v in place of the usual 3volts.
This improved it dramatically, but how do I know what is too much stress on the motor ?
I suppose it is related to how much the motor is slowed down in the milk, in which case what is the best way to measure the rotation speed ?
Simon.

Someone who actually knows will be along in a minute but from what I
remember of physics at school I think the Back EMF is the key factor here.

When a DC motor is running freely it's not only consuming but also
generating electricity and the net power running through the coils is
relatively low. Relative to start-up power - or in your case, full load
power - that is. I suspect what really matters to the motor is how much
maximum current is passing for how long and if you can wire an ammeter
in series, you can find this out.

Nick

On Wednesday, 29 November 2017 19:08:26 UTC, sm_jamieson wrote:
I have an aerolatte milk frother that is just about OK to make cappuccino style foam when the batteries are new. So having returned an espresso maker due to the feebleness of the steam outlet, I went back to the aerolatte frother, and tried it on 4.5v and 6v in place of the usual 3volts.
This improved it dramatically, but how do I know what is too much stress on the motor ?
I suppose it is related to how much the motor is slowed down in the milk, in which case what is the best way to measure the rotation speed ?
Simon.

If it's rated at eg 3v for 2 minutes, it'll run way less time before frying on 6v.


NT

On 29/11/17 20:19, wrote:
On Wednesday, 29 November 2017 19:08:26 UTC, sm_jamieson wrote:
I have an aerolatte milk frother that is just about OK to make cappuccino style foam when the batteries are new. So having returned an espresso maker due to the feebleness of the steam outlet, I went back to the aerolatte frother, and tried it on 4.5v and 6v in place of the usual 3volts.
This improved it dramatically, but how do I know what is too much stress on the motor ?
I suppose it is related to how much the motor is slowed down in the milk, in which case what is the best way to measure the rotation speed ?
Simon.

If it's rated at eg 3v for 2 minutes, it'll run way less time before frying on 6v.



All depoends on the load. My model planes were running nominal 6v
brushed can motors on 11v+ lithiums, and provided I geared them down and
let them rev on lowish currents the limiting factor was the cheap and
nasty brushes..

I got about double the power and 50% more efficiency than people running
then 'on spec'

for a 3v motor try a single li-ion cell at 4.2v fully charged, 3.8v flat..



NT



--
New Socialism consists essentially in being seen to have your heart in
the right place whilst your head is in the clouds and your hand is in
someone else's pocket.

On Wednesday, 29 November 2017 20:26:50 UTC, The Natural Philosopher wrote:
On 29/11/17 20:19, tabbypurr wrote:
On Wednesday, 29 November 2017 19:08:26 UTC, sm_jamieson wrote:

I have an aerolatte milk frother that is just about OK to make cappuccino style foam when the batteries are new. So having returned an espresso maker due to the feebleness of the steam outlet, I went back to the aerolatte frother, and tried it on 4.5v and 6v in place of the usual 3volts.
This improved it dramatically, but how do I know what is too much stress on the motor ?
I suppose it is related to how much the motor is slowed down in the milk, in which case what is the best way to measure the rotation speed ?
Simon.

If it's rated at eg 3v for 2 minutes, it'll run way less time before frying on 6v.



All depoends on the load. My model planes were running nominal 6v
brushed can motors on 11v+ lithiums, and provided I geared them down and
let them rev on lowish currents the limiting factor was the cheap and
nasty brushes..

I got about double the power and 50% more efficiency than people running
then 'on spec'

for a 3v motor try a single li-ion cell at 4.2v fully charged, 3.8v flat...

Are you suggesting that in a highly cost conscious consumer appliance the motor might be bigger than it needs to be when run on 3v? I would suggest that if anything it's smaller than it should be.


NT

Its not so much the speed but the current taken to maintain the speed and
the torque. Often pulsed dc can maintain a slower speed but with more
torque, and as the duty cycle is lower the motor might last longer, assuming
it is a standard brushed type not some kind of electronic speed adjustable
one, which form you comments about volts, is unlikely.

Its all down to design and build quality. If its a cheap device it may just
be that the short life is the price you pay for it working with more volts.
Brian

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----- -
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please!
"sm_jamieson" wrote in message
...
I have an aerolatte milk frother that is just about OK to make cappuccino
style foam when the batteries are new. So having returned an espresso maker
due to the feebleness of the steam outlet, I went back to the aerolatte
frother, and tried it on 4.5v and 6v in place of the usual 3volts.
This improved it dramatically, but how do I know what is too much stress on
the motor ?
I suppose it is related to how much the motor is slowed down in the milk, in
which case what is the best way to measure the rotation speed ?
Simon.

Of course if its over engineered it may be OK as I said in my other reply.
My take would be find a wall wart to power it at a reasonable current just
a bit up from the nominal you see at 3 v and it will probably give you as
long a life. Make sure of course that the wall wart is rated for the start
up current first. I have an issue with a shaver control circuit which won't
let the motor start even though the battery condition is not too bad. I
suspect the motor is wearing out and taking more current to start due to
wear on the brushes etc.
Brian

--
----- -
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please!
wrote in message
...
On Wednesday, 29 November 2017 19:08:26 UTC, sm_jamieson wrote:
I have an aerolatte milk frother that is just about OK to make cappuccino
style foam when the batteries are new. So having returned an espresso
maker due to the feebleness of the steam outlet, I went back to the
aerolatte frother, and tried it on 4.5v and 6v in place of the usual
3volts.
This improved it dramatically, but how do I know what is too much stress
on the motor ?
I suppose it is related to how much the motor is slowed down in the milk,
in which case what is the best way to measure the rotation speed ?
Simon.

If it's rated at eg 3v for 2 minutes, it'll run way less time before frying
on 6v.


NT

On 29/11/17 20:32, wrote:
On Wednesday, 29 November 2017 20:26:50 UTC, The Natural Philosopher wrote:
On 29/11/17 20:19, tabbypurr wrote:
On Wednesday, 29 November 2017 19:08:26 UTC, sm_jamieson wrote:

I have an aerolatte milk frother that is just about OK to make cappuccino style foam when the batteries are new. So having returned an espresso maker due to the feebleness of the steam outlet, I went back to the aerolatte frother, and tried it on 4.5v and 6v in place of the usual 3volts.
This improved it dramatically, but how do I know what is too much stress on the motor ?
I suppose it is related to how much the motor is slowed down in the milk, in which case what is the best way to measure the rotation speed ?
Simon.

If it's rated at eg 3v for 2 minutes, it'll run way less time before frying on 6v.



All depoends on the load. My model planes were running nominal 6v
brushed can motors on 11v+ lithiums, and provided I geared them down and
let them rev on lowish currents the limiting factor was the cheap and
nasty brushes..

I got about double the power and 50% more efficiency than people running
then 'on spec'

for a 3v motor try a single li-ion cell at 4.2v fully charged, 3.8v flat..

Are you suggesting that in a highly cost conscious consumer appliance the motor might be bigger than it needs to be when run on 3v? I would suggest that if anything it's smaller than it should be.

Yes, I am suggesting that.

These motors are churned out un vast numbers in far east factories by
the likes of mabuchi, sagami etc etc.

The voltage rating is practically irrelevanyt. In reality motors do not
have a voltage rating. They have a current rating, a maxium heat
dissipation, an RPM per volt rating, and an RPM limit, and a brush and
bearing wear limit.

Usually to keep costs down they wont habve a gearbox. that means
operaring a bigger motor at lower voltage and RPM.

For example my '6v' motors actually generated best power and effeiciency
at aroudn 24v and 50,000 RPM or would if brush bounce wouldnt stop them
getting there. So I ran them around 25,000/11v and stuck a 3:1 gearbox
on. 75% efficiency

Better than massive current at 6v and say 10k rpm 50% efficiency running
VERY hot.


The limiting factor on your frother will be heat. Take te ferriote
magnets past about 150C and the curie point and they will lose
magnetsim. As the magnetism goes, the motor will speed UP as it isnt
generating the back EMF any more, and take even MORE cirrent and the
next thing is magic smoke coming out of the things.

So monitor the heat.




NT



--
Ideas are more powerful than guns. We would not let our enemies have
guns, why should we let them have ideas?

Josef Stalin

On Thursday, 30 November 2017 11:00:08 UTC, The Natural Philosopher wrote:
On 29/11/17 20:32, tabbypurr wrote:
On Wednesday, 29 November 2017 20:26:50 UTC, The Natural Philosopher wrote:
On 29/11/17 20:19, tabbypurr wrote:
On Wednesday, 29 November 2017 19:08:26 UTC, sm_jamieson wrote:

I have an aerolatte milk frother that is just about OK to make cappuccino style foam when the batteries are new. So having returned an espresso maker due to the feebleness of the steam outlet, I went back to the aerolatte frother, and tried it on 4.5v and 6v in place of the usual 3volts.
This improved it dramatically, but how do I know what is too much stress on the motor ?
I suppose it is related to how much the motor is slowed down in the milk, in which case what is the best way to measure the rotation speed ?
Simon.

If it's rated at eg 3v for 2 minutes, it'll run way less time before frying on 6v.



All depoends on the load. My model planes were running nominal 6v
brushed can motors on 11v+ lithiums, and provided I geared them down and
let them rev on lowish currents the limiting factor was the cheap and
nasty brushes..

I got about double the power and 50% more efficiency than people running
then 'on spec'

for a 3v motor try a single li-ion cell at 4.2v fully charged, 3.8v flat..

Are you suggesting that in a highly cost conscious consumer appliance the motor might be bigger than it needs to be when run on 3v? I would suggest that if anything it's smaller than it should be.

Yes, I am suggesting that.

These motors are churned out un vast numbers in far east factories by
the likes of mabuchi, sagami etc etc.

The voltage rating is practically irrelevanyt. In reality motors do not
have a voltage rating. They have a current rating, a maxium heat
dissipation, an RPM per volt rating, and an RPM limit, and a brush and
bearing wear limit.

Fan torque goes up rapidly as rpm increases. Current is proportional to torque. Thus by feeding the thing more volts he's also feeding it more amps. Thus it can run for less time. Typically handheld kitchen appliances already have short duty cycle ratings.


NT

On 30/11/17 11:14, wrote:
On Thursday, 30 November 2017 11:00:08 UTC, The Natural Philosopher
wrote:


These motors are churned out un vast numbers in far east factories
by the likes of mabuchi, sagami etc etc.

The voltage rating is practically irrelevanyt. In reality motors do
not have a voltage rating. They have a current rating, a maxium
heat dissipation, an RPM per volt rating, and an RPM limit, and a
brush and bearing wear limit.

Fan torque goes up rapidly as rpm increases.

Cube law I think on my model planes. Can't remember, Certainly at least
square law.


Current is proportional to torque. Thus by feeding the thing more
volts he's also feeding it more amps.

Correct.

Thus it can run for less time.

Non reliable sequitur. All depends on how near the limit it is. My whole
point is that motors that are muppet proof and can probably be safely
stalled on 3V are, provided you understand what you ate doing, probably
fine at 24V if you gear them down, and probvably fine at 6V of you don't
stall them.


Typically handheld kitchen appliances already have short duty cycle
ratings.


So do model planes :-)

one hour to charge, 5 minutes flying time.




NT



--
€œIt is hard to imagine a more stupid decision or more dangerous way of
making decisions than by putting those decisions in the hands of people
who pay no price for being wrong.€�

Thomas Sowell