Anyone know how these work?

The foot control of my wife's 1980's Singer sewing machine started
emitting smoke a couple of days ago and, at one stage, the motor ran
without having her foot on the pedal.

Mr Google suggests that it contains a capacitor which, if it develops a
short circuit, can exhibit these symptoms. I opened it up to have a look
and there was was a nasty smell from the vicinity of the capacitor, but
nothing obviously burnt out. I've ordered a new capacitor, anyway, and
will fit it when it arrives. Meanwhile, I've blown all the dust out of
the foot control with an airline, and tested it - and it seems to be
working ok.

But speed control isn't very progressive - it tends to be virtually all
or nothing, like a car accelerator which only has two positions. [This
isn't new - it was like this before it started smoking.]

So I'm trying to understand how the speed control is supposed to work.

https://app.box.com/s/inzt3elo35uq13srz5fqi7qg15ei7z8x shows a photo of
the foot control with the hinged top open. The brown and blue wires are
connected together via a ceramic cylinder which has a piece of carbon
rod protruding from each end. The one at the left hand end is spring-loaded.

When the lid is closed and pressed down, a post on its underside presses
down on the centre of the long copper? strip so that it makes contact
with another strip below (hidden in the photo) which is connected to the
brown wire - swiching on the motor. As the lid is pressed down more, the
upturned part at the left hand end of the copper strip moves to the
right and presses on the spring-loaded carbon rod. I assume that it is
somehow meant to increase the motor speed, but I don't understand what's
going on inside the ceramic cylinder.

Can anyone throw any light on this?
--
Cheers,
Roger

On Thursday, 5 March 2020 23:10:06 UTC, Roger Mills wrote:

Anyone know how these work?
The foot control of my wife's 1980's Singer sewing machine started
emitting smoke a couple of days ago and, at one stage, the motor ran
without having her foot on the pedal.

Mr Google suggests that it contains a capacitor which, if it develops a
short circuit, can exhibit these symptoms. I opened it up to have a look
and there was was a nasty smell from the vicinity of the capacitor, but
nothing obviously burnt out. I've ordered a new capacitor, anyway, and
will fit it when it arrives. Meanwhile, I've blown all the dust out of
the foot control with an airline, and tested it - and it seems to be
working ok.

But speed control isn't very progressive - it tends to be virtually all
or nothing, like a car accelerator which only has two positions. [This
isn't new - it was like this before it started smoking.]

So I'm trying to understand how the speed control is supposed to work.

https://app.box.com/s/inzt3elo35uq13srz5fqi7qg15ei7z8x shows a photo of
the foot control with the hinged top open. The brown and blue wires are
connected together via a ceramic cylinder which has a piece of carbon
rod protruding from each end. The one at the left hand end is spring-loaded.

When the lid is closed and pressed down, a post on its underside presses
down on the centre of the long copper? strip so that it makes contact
with another strip below (hidden in the photo) which is connected to the
brown wire - swiching on the motor. As the lid is pressed down more, the
upturned part at the left hand end of the copper strip moves to the
right and presses on the spring-loaded carbon rod. I assume that it is
somehow meant to increase the motor speed, but I don't understand what's
going on inside the ceramic cylinder.

Can anyone throw any light on this?

The white tube is a variable carbon resistor. Increasing pressure on the end lowers the resistance. It oughta be progressive. And shouldn't smoke


NT

On Thursday, 5 March 2020 23:10:06 UTC, Roger Mills wrote:
Anyone know how these work?

The foot control of my wife's 1980's Singer sewing machine started
emitting smoke a couple of days ago and, at one stage, the motor ran
without having her foot on the pedal.

Mr Google suggests that it contains a capacitor which, if it develops a
short circuit, can exhibit these symptoms. I opened it up to have a look
and there was was a nasty smell from the vicinity of the capacitor, but
nothing obviously burnt out. I've ordered a new capacitor, anyway, and
will fit it when it arrives. Meanwhile, I've blown all the dust out of
the foot control with an airline, and tested it - and it seems to be
working ok.

But speed control isn't very progressive - it tends to be virtually all
or nothing, like a car accelerator which only has two positions. [This
isn't new - it was like this before it started smoking.]

So I'm trying to understand how the speed control is supposed to work.

https://app.box.com/s/inzt3elo35uq13srz5fqi7qg15ei7z8x shows a photo of
the foot control with the hinged top open. The brown and blue wires are
connected together via a ceramic cylinder which has a piece of carbon
rod protruding from each end. The one at the left hand end is spring-loaded.

When the lid is closed and pressed down, a post on its underside presses
down on the centre of the long copper? strip so that it makes contact
with another strip below (hidden in the photo) which is connected to the
brown wire - swiching on the motor. As the lid is pressed down more, the
upturned part at the left hand end of the copper strip moves to the
right and presses on the spring-loaded carbon rod. I assume that it is
somehow meant to increase the motor speed, but I don't understand what's
going on inside the ceramic cylinder.

Can anyone throw any light on this?
--
Cheers,
Roger

There is a pile of carbon disks in a tube. Pressing on the foot control squeezes them together thus lowering resistance and increasing motor speed.

On Friday, 6 March 2020 06:50:18 UTC, harry wrote:
On Thursday, 5 March 2020 23:10:06 UTC, Roger Mills wrote:
Anyone know how these work?

The foot control of my wife's 1980's Singer sewing machine started
emitting smoke a couple of days ago and, at one stage, the motor ran
without having her foot on the pedal.

Mr Google suggests that it contains a capacitor which, if it develops a
short circuit, can exhibit these symptoms. I opened it up to have a look
and there was was a nasty smell from the vicinity of the capacitor, but
nothing obviously burnt out. I've ordered a new capacitor, anyway, and
will fit it when it arrives. Meanwhile, I've blown all the dust out of
the foot control with an airline, and tested it - and it seems to be
working ok.

But speed control isn't very progressive - it tends to be virtually all
or nothing, like a car accelerator which only has two positions. [This
isn't new - it was like this before it started smoking.]

So I'm trying to understand how the speed control is supposed to work.

https://app.box.com/s/inzt3elo35uq13srz5fqi7qg15ei7z8x shows a photo of
the foot control with the hinged top open. The brown and blue wires are
connected together via a ceramic cylinder which has a piece of carbon
rod protruding from each end. The one at the left hand end is spring-loaded.

When the lid is closed and pressed down, a post on its underside presses
down on the centre of the long copper? strip so that it makes contact
with another strip below (hidden in the photo) which is connected to the
brown wire - swiching on the motor. As the lid is pressed down more, the
upturned part at the left hand end of the copper strip moves to the
right and presses on the spring-loaded carbon rod. I assume that it is
somehow meant to increase the motor speed, but I don't understand what's
going on inside the ceramic cylinder.

Can anyone throw any light on this?
--
Cheers,
Roger

There is a pile of carbon disks in a tube. Pressing on the foot control squeezes them together thus lowering resistance and increasing motor speed.

It can be opened up and the disks cleaned up/smoothed with fine sandpaper.

Roger Mills wrote:

Mr Google suggests that it contains a capacitor which, if it develops a
short circuit, can exhibit these symptoms

The oblong capacitor might just be for suppression, it looks like a
metallised film type, older ones are susceptible to developing cracks in
their case, try de-soldering it or snipping it out ... if that helps
then an example replacement X2 cap would be

https://uk.farnell.com/epcos/b32922c3104k000/cap-0-1-f-10-pp/dp/2728566

On 05/03/2020 23:10, Roger Mills wrote:
Anyone know how these work?

The foot control of my wife's 1980's Singer sewing machine started
emitting smoke a couple of days ago and, at one stage, the motor ran
without having her foot on the pedal.

Mr Google suggests that it contains a capacitor which, if it develops a
short circuit, can exhibit these symptoms. I opened it up to have a look
and there was was a nasty smell from the vicinity of the capacitor, but
nothing obviously burnt out. I've ordered a new capacitor, anyway, and
will fit it when it arrives. Meanwhile, I've blown all the dust out of
the foot control with an airline, and tested it - and it seems to be
working ok.

But speed control isn't very progressive - it tends to be virtually all
or nothing, like a car accelerator which only has two positions. [This
isn't new - it was like this before it started smoking.]

So I'm trying to understand how the speed control is supposed to work.

https://app.box.com/s/inzt3elo35uq13srz5fqi7qg15ei7z8x shows a photo of
the foot control with the hinged top open. The brown and blue wires are
connected together via a ceramic cylinder which has a piece of carbon
rod protruding from each end. The one at the left hand end is
spring-loaded.

When the lid is closed and pressed down, a post on its underside presses
down on the centre of the long copper? strip so that it makes contact
with another strip below (hidden in the photo) which is connected to the
brown wire - swiching on the motor. As the lid is pressed down more, the
upturned part at the left hand end of the copper strip moves to the
right and presses on the spring-loaded carbon rod. I assume that it is
somehow meant to increase the motor speed, but I don't understand what's
going on inside the ceramic cylinder.

Can anyone throw any light on this?

May be a primitive carbon variable resistor. More pressure = less
resistance. Or the ceramic cylinder has a sliding contact on a carbon
rod to be a variable resistor.


You can get repair kits for these (
https://www.ebay.co.uk/itm/VINTAGE-S...S/262084594501
) - that silvery cap has GONE - but I'd definitely be looking to
replace with something electronic.





--
"The great thing about Glasgow is that if there's a nuclear attack it'll
look exactly the same afterwards."

Billy Connolly

Sounds a bit crude to me. Is the motor a brushed type or not?
I would have expected a triac in the circuit if its a brushed motor, with a
circuit a bit like a light dimmer but with some kind of protection due to
the inductive load it prevents.
If the variable resistor is worn then jumpy control will be the result.
Brian

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

Blind user, so no pictures please
Note this Signature is meaningless.!
wrote in message
...
On Thursday, 5 March 2020 23:10:06 UTC, Roger Mills wrote:

Anyone know how these work?
The foot control of my wife's 1980's Singer sewing machine started
emitting smoke a couple of days ago and, at one stage, the motor ran
without having her foot on the pedal.

Mr Google suggests that it contains a capacitor which, if it develops a
short circuit, can exhibit these symptoms. I opened it up to have a look
and there was was a nasty smell from the vicinity of the capacitor, but
nothing obviously burnt out. I've ordered a new capacitor, anyway, and
will fit it when it arrives. Meanwhile, I've blown all the dust out of
the foot control with an airline, and tested it - and it seems to be
working ok.

But speed control isn't very progressive - it tends to be virtually all
or nothing, like a car accelerator which only has two positions. [This
isn't new - it was like this before it started smoking.]

So I'm trying to understand how the speed control is supposed to work.

https://app.box.com/s/inzt3elo35uq13srz5fqi7qg15ei7z8x shows a photo of
the foot control with the hinged top open. The brown and blue wires are
connected together via a ceramic cylinder which has a piece of carbon
rod protruding from each end. The one at the left hand end is
spring-loaded.

When the lid is closed and pressed down, a post on its underside presses
down on the centre of the long copper? strip so that it makes contact
with another strip below (hidden in the photo) which is connected to the
brown wire - swiching on the motor. As the lid is pressed down more, the
upturned part at the left hand end of the copper strip moves to the
right and presses on the spring-loaded carbon rod. I assume that it is
somehow meant to increase the motor speed, but I don't understand what's
going on inside the ceramic cylinder.

Can anyone throw any light on this?

The white tube is a variable carbon resistor. Increasing pressure on the
end lowers the resistance. It oughta be progressive. And shouldn't smoke



NT

That sounds awfully crude to me, I'd have suspected something like a drill
speed control circuit.
Brian

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

Blind user, so no pictures please
Note this Signature is meaningless.!
"harry" wrote in message
...
On Thursday, 5 March 2020 23:10:06 UTC, Roger Mills wrote:
Anyone know how these work?

The foot control of my wife's 1980's Singer sewing machine started
emitting smoke a couple of days ago and, at one stage, the motor ran
without having her foot on the pedal.

Mr Google suggests that it contains a capacitor which, if it develops a
short circuit, can exhibit these symptoms. I opened it up to have a look
and there was was a nasty smell from the vicinity of the capacitor, but
nothing obviously burnt out. I've ordered a new capacitor, anyway, and
will fit it when it arrives. Meanwhile, I've blown all the dust out of
the foot control with an airline, and tested it - and it seems to be
working ok.

But speed control isn't very progressive - it tends to be virtually all
or nothing, like a car accelerator which only has two positions. [This
isn't new - it was like this before it started smoking.]

So I'm trying to understand how the speed control is supposed to work.

https://app.box.com/s/inzt3elo35uq13srz5fqi7qg15ei7z8x shows a photo of
the foot control with the hinged top open. The brown and blue wires are
connected together via a ceramic cylinder which has a piece of carbon
rod protruding from each end. The one at the left hand end is
spring-loaded.

When the lid is closed and pressed down, a post on its underside presses
down on the centre of the long copper? strip so that it makes contact
with another strip below (hidden in the photo) which is connected to the
brown wire - swiching on the motor. As the lid is pressed down more, the
upturned part at the left hand end of the copper strip moves to the
right and presses on the spring-loaded carbon rod. I assume that it is
somehow meant to increase the motor speed, but I don't understand what's
going on inside the ceramic cylinder.

Can anyone throw any light on this?
--
Cheers,
Roger

There is a pile of carbon disks in a tube. Pressing on the foot control
squeezes them together thus lowering resistance and increasing motor
speed.

On Thu, 5 Mar 2020 17:08:01 -0800 (PST), wrote:

The white tube is a variable carbon resistor. Increasing pressure on the end lowers the resistance. It oughta be progressive. And shouldn't smoke

This.

It's a stack of carbon disks. The resistance changes with pressure.

Can't remeber if non-destructive disassembly is possible. If so I'd try a
reshuffle of the disks.


Thomas Prufer

Brian Gaff (Sofa 2) wrote:

That sounds awfully crude to me, I'd have suspected something like a drill
speed control circuit.
Brian

The design predates solid state electronics.

--

Roger Hayter

On 06/03/2020 09:08, Roger Hayter wrote:
Brian Gaff (Sofa 2) wrote:

That sounds awfully crude to me, I'd have suspected something like a drill
speed control circuit.
Brian

The design predates solid state electronics.

ISTR a big wirewound pot in me mums control. 60s vintage.




--
€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

On 06/03/2020 01:08, wrote:
On Thursday, 5 March 2020 23:10:06 UTC, Roger Mills wrote:

Anyone know how these work?
The foot control of my wife's 1980's Singer sewing machine started
emitting smoke a couple of days ago and, at one stage, the motor ran
without having her foot on the pedal.

Mr Google suggests that it contains a capacitor which, if it develops a
short circuit, can exhibit these symptoms. I opened it up to have a look
and there was was a nasty smell from the vicinity of the capacitor, but
nothing obviously burnt out. I've ordered a new capacitor, anyway, and
will fit it when it arrives. Meanwhile, I've blown all the dust out of
the foot control with an airline, and tested it - and it seems to be
working ok.

But speed control isn't very progressive - it tends to be virtually all
or nothing, like a car accelerator which only has two positions. [This
isn't new - it was like this before it started smoking.]

So I'm trying to understand how the speed control is supposed to work.

https://app.box.com/s/inzt3elo35uq13srz5fqi7qg15ei7z8x shows a photo of
the foot control with the hinged top open. The brown and blue wires are
connected together via a ceramic cylinder which has a piece of carbon
rod protruding from each end. The one at the left hand end is spring-loaded.

When the lid is closed and pressed down, a post on its underside presses
down on the centre of the long copper? strip so that it makes contact
with another strip below (hidden in the photo) which is connected to the
brown wire - swiching on the motor. As the lid is pressed down more, the
upturned part at the left hand end of the copper strip moves to the
right and presses on the spring-loaded carbon rod. I assume that it is
somehow meant to increase the motor speed, but I don't understand what's
going on inside the ceramic cylinder.

Can anyone throw any light on this?

The white tube is a variable carbon resistor. Increasing pressure on the end lowers the resistance. It oughta be progressive. And shouldn't smoke


Yes, it's a 'carbon pile rheostat' patented by Singer in 1949 - lots of
carbon discs in a tube and you lower the resistance by squeezing them
together. Google the phrase and there are some instructions on
repairing them.


--
Cheers
Clive

On 06/03/2020 07:54, The Natural Philosopher wrote:
On 05/03/2020 23:10, Roger Mills wrote:
Anyone know how these work?

The foot control of my wife's 1980's Singer sewing machine started
emitting smoke a couple of days ago and, at one stage, the motor ran
without having her foot on the pedal.

Mr Google suggests that it contains a capacitor which, if it develops
a short circuit, can exhibit these symptoms. I opened it up to have a
look and there was was a nasty smell from the vicinity of the
capacitor, but nothing obviously burnt out. I've ordered a new
capacitor, anyway, and will fit it when it arrives. Meanwhile, I've
blown all the dust out of the foot control with an airline, and tested
it - and it seems to be working ok.

But speed control isn't very progressive - it tends to be virtually
all or nothing, like a car accelerator which only has two positions.
[This isn't new - it was like this before it started smoking.]

So I'm trying to understand how the speed control is supposed to work.

https://app.box.com/s/inzt3elo35uq13srz5fqi7qg15ei7z8x shows a photo
of the foot control with the hinged top open. The brown and blue wires
are connected together via a ceramic cylinder which has a piece of
carbon rod protruding from each end. The one at the left hand end is
spring-loaded.

When the lid is closed and pressed down, a post on its underside
presses down on the centre of the long copper? strip so that it makes
contact with another strip below (hidden in the photo) which is
connected to the brown wire - swiching on the motor. As the lid is
pressed down more, the upturned part at the left hand end of the
copper strip moves to the right and presses on the spring-loaded
carbon rod. I assume that it is somehow meant to increase the motor
speed, but I don't understand what's going on inside the ceramic
cylinder.

Can anyone throw any light on this?

May be a primitive carbon variable resistor. More pressure = less
resistance. Or the ceramic cylinder hasÂ* a sliding contact on a carbon
rod to be a variable resistor.


You can get repair kits for these (
https://www.ebay.co.uk/itm/VINTAGE-S...S/262084594501
)Â* - that silvery cap has GONE - but I'd definitely be looking to
replace with something electronic.


Thanks, but that 'kit' consists only of a capacitor - and I have already
ordered a similar one from a different source. Look like I could so with
replacing the carbon pile rheostat - but no-one seems to sell those.
--
Cheers,
Roger

On 06/03/2020 09:08, Roger Hayter wrote:
Brian Gaff (Sofa 2) wrote:

That sounds awfully crude to me, I'd have suspected something like a drill
speed control circuit.
Brian

The design predates solid state electronics.


Indeed. There's nothing 'electronic' about mine.
--
Cheers,
Roger

On 06/03/2020 10:33, Clive Arthur wrote:
On 06/03/2020 01:08, wrote:


The white tube is a variable carbon resistor. Increasing pressure on
the end lowers the resistance. It oughta be progressive. And shouldn't
smoke


Yes, it's a 'carbon pile rheostat' patented by Singer in 1949 - lots of
carbon discs in a tube and you lower the resistance by squeezing them
together.Â* Google the phrase and there are some instructions on
repairing them.



Useful, thanks. I might have a go, but I don't have a source of spare
discs if they're needed.
--
Cheers,
Roger

On 06/03/2020 08:33, Brian Gaff (Sofa 2) wrote:
That sounds awfully crude to me, I'd have suspected something like a drill
speed control circuit.
Brian


It probably depends on the age of the machine. The clue is in the
original post - the machine is 40 years old.

--
mailto : news {at} admac {dot} myzen {dot} co {dot} uk

Roger Mills wrote in
:

On 06/03/2020 07:54, The Natural Philosopher wrote:


Thanks, but that 'kit' consists only of a capacitor - and I have
already ordered a similar one from a different source. Look like I
could so with replacing the carbon pile rheostat - but no-one seems to
sell those.

I wonder if there is an all electronic replacement.

On Friday, 6 March 2020 22:49:53 UTC, John wrote:
Roger Mills wrote in
:

On 06/03/2020 07:54, The Natural Philosopher wrote:


Thanks, but that 'kit' consists only of a capacitor - and I have
already ordered a similar one from a different source. Look like I
could so with replacing the carbon pile rheostat - but no-one seems to
sell those.

I wonder if there is an all electronic replacement.

I expect somewhere there are generic controllers that will work with a wide range of machines. Probably any old school foot controller would work if you fitted the lead that goes to the machine to it.


NT

On 06/03/2020 22:49, John wrote:
Roger Mills wrote in
:

On 06/03/2020 07:54, The Natural Philosopher wrote:


Thanks, but that 'kit' consists only of a capacitor - and I have
already ordered a similar one from a different source. Look like I
could so with replacing the carbon pile rheostat - but no-one seems to
sell those.

I wonder if there is an all electronic replacement.

Oh yes. Motors on these things are all pretty similar. A light dimmer
would probably work - badly.

Plenty of either same type of unit or electronic alternatives on Ebay


--
"Strange as it seems, no amount of learning can cure stupidity, and
higher education positively fortifies it."

- Stephen Vizinczey

On Friday, 6 March 2020 22:49:53 UTC, John wrote:
Roger Mills wrote in
:

On 06/03/2020 07:54, The Natural Philosopher wrote:


Thanks, but that 'kit' consists only of a capacitor - and I have
already ordered a similar one from a different source. Look like I
could so with replacing the carbon pile rheostat - but no-one seems to
sell those.

I wonder if there is an all electronic replacement.

The voltage spikes generated by that sort of motor would probably ruin an electronic device. An additional capacitor might fix the problem.

In article , alan_m
wrote:
On 06/03/2020 08:33, Brian Gaff (Sofa 2) wrote:
That sounds awfully crude to me, I'd have suspected something like a
drill speed control circuit. Brian


It probably depends on the age of the machine. The clue is in the
original post - the machine is 40 years old.

we did have transistors then.

--
from KT24 in Surrey, England
"I'd rather die of exhaustion than die of boredom" Thomas Carlyle

Clive Arthur brought next idea :
Yes, it's a 'carbon pile rheostat' patented by Singer in 1949 - lots of
carbon discs in a tube and you lower the resistance by squeezing them
together. Google the phrase and there are some instructions on repairing
them.

I always had in mind to try to put together something better, like a
TRIAC control with speed feedback. On the rare occasions I have used
out machine, I found the sudden take off at speed awkward to control
and use. Someone must have tried such an improved design?

On Saturday, 7 March 2020 07:39:23 UTC, harry wrote:
On Friday, 6 March 2020 22:49:53 UTC, John wrote:
Roger Mills wrote in
:

On 06/03/2020 07:54, The Natural Philosopher wrote:


Thanks, but that 'kit' consists only of a capacitor - and I have
already ordered a similar one from a different source. Look like I
could so with replacing the carbon pile rheostat - but no-one seems to
sell those.

I wonder if there is an all electronic replacement.

The voltage spikes generated by that sort of motor would probably ruin an electronic device. An additional capacitor might fix the problem.

Not sure how electronic that old a sewing machine would have?

This is a link to replacement controllers and how to select them:

https://www.uksewing.com/pages/singer-foot-control

My (limited) experience of Singers of that sort of era would lead me to consider replacement of the machine (unless it is something special). Partner traded in her old (non-Singer) machine for a very nice secondhand Bernina.

On 07/03/2020 10:31, charles wrote:
In article , alan_m
wrote:
On 06/03/2020 08:33, Brian Gaff (Sofa 2) wrote:
That sounds awfully crude to me, I'd have suspected something like a
drill speed control circuit. Brian


It probably depends on the age of the machine. The clue is in the
original post - the machine is 40 years old.

we did have transistors then.

1980? We did BUT mains level transistors were very expensive and even
triacs and SCRS were pretty dear.

The real power stuff - 400V MOSFET switches - didn't turn up till I was
out of that game in the late 80s.

And the intelligence to drive them reliably only got cheap in this century.


--
A lie can travel halfway around the world while the truth is putting on
its shoes.

On Saturday, 7 March 2020 10:40:08 UTC, wrote:
Clive Arthur brought next idea :

Yes, it's a 'carbon pile rheostat' patented by Singer in 1949 - lots of
carbon discs in a tube and you lower the resistance by squeezing them
together. Google the phrase and there are some instructions on repairing
them.

I always had in mind to try to put together something better, like a
TRIAC control with speed feedback. On the rare occasions I have used
out machine, I found the sudden take off at speed awkward to control
and use. Someone must have tried such an improved design?

Of course, modern Berninas use proper control. But budget machines just used a resistor. The main difference it makes is at very low speeds, where a decent control has pretty much perfect control.


NT

In article ,
The Natural Philosopher wrote:
On 07/03/2020 10:31, charles wrote:
In article , alan_m
wrote:
On 06/03/2020 08:33, Brian Gaff (Sofa 2) wrote:
That sounds awfully crude to me, I'd have suspected something like a
drill speed control circuit. Brian


It probably depends on the age of the machine. The clue is in the
original post - the machine is 40 years old.

we did have transistors then.

1980? We did BUT mains level transistors were very expensive and even
triacs and SCRS were pretty dear.

Triacs were about £1 each. I built a 24 way dimmer rack in the mid 70s.

The real power stuff - 400V MOSFET switches - didn't turn up till I was
out of that game in the late 80s.

And the intelligence to drive them reliably only got cheap in this
century.

--
from KT24 in Surrey, England
"I'd rather die of exhaustion than die of boredom" Thomas Carlyle

charles wrote:

In article , alan_m
wrote:
On 06/03/2020 08:33, Brian Gaff (Sofa 2) wrote:
That sounds awfully crude to me, I'd have suspected something like a
drill speed control circuit. Brian


It probably depends on the age of the machine. The clue is in the
original post - the machine is 40 years old.

we did have transistors then.

I suspect the pedal design is at least twice that age, probably
somewhere between 1910 and 1930. Quick googling doesn't really give an
answer, but electric Singer machines were first made in 1910 and must
have had some sort of speed control.



--

Roger Hayter

On Saturday, 7 March 2020 07:39:23 UTC, harry wrote:
On Friday, 6 March 2020 22:49:53 UTC, John wrote:
Roger Mills wrote in
:

On 06/03/2020 07:54, The Natural Philosopher wrote:


Thanks, but that 'kit' consists only of a capacitor - and I have
already ordered a similar one from a different source. Look like I
could so with replacing the carbon pile rheostat - but no-one seems to
sell those.

I wonder if there is an all electronic replacement.

The voltage spikes generated by that sort of motor would probably ruin an electronic device. An additional capacitor might fix the problem.

Not sure how electronic that old a sewing machine would have?

This is a link to replacement controllers and how to select them:

https://www.uksewing.com/pages/singer-foot-control

My (limited) experience of Singers of that sort of era would lead me to consider replacement of the machine (unless it is something special). Partner traded in her old (non-Singer) machine for a very nice secondhand Bernina.

"The Natural Philosopher" wrote in message
...
On 07/03/2020 10:31, charles wrote:
In article , alan_m
wrote:
On 06/03/2020 08:33, Brian Gaff (Sofa 2) wrote:
That sounds awfully crude to me, I'd have suspected something like a
drill speed control circuit. Brian


It probably depends on the age of the machine. The clue is in the
original post - the machine is 40 years old.

we did have transistors then.

1980? We did BUT mains level transistors were very expensive and even
triacs and SCRS were pretty dear.

The real power stuff - 400V MOSFET switches - didn't turn up till I was
out of that game in the late 80s.

And the intelligence to drive them reliably only got cheap in this
century.

That last is bull****.

On Sun, 8 Mar 2020 06:10:37 +1100, turnipt ****er, better known as
cantankerous trolling senile geezer Rodent Speed, wrote:


That last is bull****.

You and your entire "life" is nothing but bull****, you 86-year-old trolling
senile cretin!

--
Marland revealing the senile sociopath's pathology:
"You have mentioned Alexa in a couple of threads recently, it is not a real
woman you know even if it is the only thing with a Female name that stays
around around while you talk it to it.
Poor sad git who has to resort to Usenet and electronic devices for any
interaction as all real people run a mile to get away from from you boring
them to death."
MID:

On 07/03/2020 12:14, Roger Hayter wrote:

snip

I suspect the pedal design is at least twice that age, probably
somewhere between 1910 and 1930. Quick googling doesn't really give an
answer, but electric Singer machines were first made in 1910 and must
have had some sort of speed control.


The rheostat design was patented by Singer in 1949. My guess is they
continued to use them for years because they had a warehouse full.

--
Cheers
Clive

On Saturday, 7 March 2020 19:51:11 UTC, Clive Arthur wrote:
On 07/03/2020 12:14, Roger Hayter wrote:

snip

I suspect the pedal design is at least twice that age, probably
somewhere between 1910 and 1930. Quick googling doesn't really give an
answer, but electric Singer machines were first made in 1910 and must
have had some sort of speed control.


The rheostat design was patented by Singer in 1949.

it was in widespread use before then

My guess is they
continued to use them for years because they had a warehouse full.

you're a wit for sure


NT

On Sun, 08 Mar 2020 04:00:26 -0700, tabbypurr wrote:

On Saturday, 7 March 2020 19:51:11 UTC, Clive Arthur wrote:
On 07/03/2020 12:14, Roger Hayter wrote:

snip

I suspect the pedal design is at least twice that age, probably
somewhere between 1910 and 1930. Quick googling doesn't really give
an answer, but electric Singer machines were first made in 1910 and
must have had some sort of speed control.


The rheostat design was patented by Singer in 1949.

it was in widespread use before then

My guess is they continued to use them for years because they had a
warehouse full.

you're a wit for sure

No, they had the market sewn up.


--
My posts are my copyright and if @diy_forums or Home Owners' Hub
wish to copy them they can pay me £1 a message.
Use the BIG mirror service in the UK: http://www.mirrorservice.org
*lightning surge protection* - a w_tom conductor

On 08/03/2020 11:00, wrote:
On Saturday, 7 March 2020 19:51:11 UTC, Clive Arthur wrote:
On 07/03/2020 12:14, Roger Hayter wrote:

snip

I suspect the pedal design is at least twice that age, probably
somewhere between 1910 and 1930. Quick googling doesn't really give an
answer, but electric Singer machines were first made in 1910 and must
have had some sort of speed control.


The rheostat design was patented by Singer in 1949.

it was in widespread use before then

Yes, the patent was granted in 1945, not 1949 as I wrote, it's
specifically for controlling sewing machines. One of the claims
mentions an 'improved controller of the carbon disk compression type'
which means that the rheostat was already around.

It's a US patent US2371772A - the USPTO isn't very rigorous today, maybe
they were better then.

--
Cheers
Clive

On Sunday, 8 March 2020 13:32:25 UTC, Clive Arthur wrote:
On 08/03/2020 11:00, tabbypurr wrote:
On Saturday, 7 March 2020 19:51:11 UTC, Clive Arthur wrote:
On 07/03/2020 12:14, Roger Hayter wrote:

snip

I suspect the pedal design is at least twice that age, probably
somewhere between 1910 and 1930. Quick googling doesn't really give an
answer, but electric Singer machines were first made in 1910 and must
have had some sort of speed control.


The rheostat design was patented by Singer in 1949.

it was in widespread use before then

Yes, the patent was granted in 1945, not 1949 as I wrote, it's
specifically for controlling sewing machines. One of the claims
mentions an 'improved controller of the carbon disk compression type'
which means that the rheostat was already around.

It's a US patent US2371772A - the USPTO isn't very rigorous today, maybe
they were better then.

It's just the 'improvement' that was patented then. Resistive piles were in use in the 1800s, and wirewound blocks with a wiper arm were a more common sewing machine foot control option.

I'd expect far better performance from the wiper type than a carbon pile.


NT

wrote:
It's just the 'improvement' that was patented then. Resistive piles were
in use in the 1800s, and wirewound blocks with a wiper arm were a more

In the 1800s? Do you really mean in the period 1800 to 1810? Or did
you mean some time in the 19th century? I wouldn't have thought there
was anything electric powered anywhere in the 1800 - 1810 period.

common sewing machine foot control option.

I'd expect far better performance from the wiper type than a carbon pile.


NT

--
Chris Green
·

On Sunday, 8 March 2020 19:03:07 UTC, Chris Green wrote:
tabbypurr wrote:

It's just the 'improvement' that was patented then. Resistive piles were
in use in the 1800s, and wirewound blocks with a wiper arm were a more

In the 1800s? Do you really mean in the period 1800 to 1810? Or did
you mean some time in the 19th century?

1800-1900

I wouldn't have thought there
was anything electric powered anywhere in the 1800 - 1810 period.

I believe there were frogs' legs, kites and pithballs.


NT

wrote:

On Sunday, 8 March 2020 13:32:25 UTC, Clive Arthur wrote:
On 08/03/2020 11:00, tabbypurr wrote:
On Saturday, 7 March 2020 19:51:11 UTC, Clive Arthur wrote:
On 07/03/2020 12:14, Roger Hayter wrote:

snip

I suspect the pedal design is at least twice that age, probably
somewhere between 1910 and 1930. Quick googling doesn't really give an
answer, but electric Singer machines were first made in 1910 and must
have had some sort of speed control.


The rheostat design was patented by Singer in 1949.

it was in widespread use before then

Yes, the patent was granted in 1945, not 1949 as I wrote, it's
specifically for controlling sewing machines. One of the claims
mentions an 'improved controller of the carbon disk compression type'
which means that the rheostat was already around.

It's a US patent US2371772A - the USPTO isn't very rigorous today, maybe
they were better then.

It's just the 'improvement' that was patented then. Resistive piles were
in use in the 1800s, and wirewound blocks with a wiper arm were a more
common sewing machine foot control option.

I'd expect far better performance from the wiper type than a carbon pile.


NT
I'd expect less durability and reliability.

--

Roger Hayter

In article , Bob Eager
writes
On Sun, 08 Mar 2020 04:00:26 -0700, tabbypurr wrote:

On Saturday, 7 March 2020 19:51:11 UTC, Clive Arthur wrote:
On 07/03/2020 12:14, Roger Hayter wrote:

snip

I suspect the pedal design is at least twice that age, probably
somewhere between 1910 and 1930. Quick googling doesn't really give
an answer, but electric Singer machines were first made in 1910 and
must have had some sort of speed control.


The rheostat design was patented by Singer in 1949.

it was in widespread use before then

My guess is they continued to use them for years because they had a
warehouse full.

you're a wit for sure

No, they had the market sewn up.


This thread has just broken.
--
bert

On Tuesday, 10 March 2020 20:17:54 UTC, bert wrote:
In article , Bob Eager
writes
On Sun, 08 Mar 2020 04:00:26 -0700, tabbypurr wrote:
On Saturday, 7 March 2020 19:51:11 UTC, Clive Arthur wrote:
On 07/03/2020 12:14, Roger Hayter wrote:

I suspect the pedal design is at least twice that age, probably
somewhere between 1910 and 1930. Quick googling doesn't really give
an answer, but electric Singer machines were first made in 1910 and
must have had some sort of speed control.


The rheostat design was patented by Singer in 1949.

it was in widespread use before then

My guess is they continued to use them for years because they had a
warehouse full.

you're a wit for sure

No, they had the market sewn up.


This thread has just broken.

you finally cottoned on.