OK, at last fitted the fan speed controller for the downstairs loo, and it causes the fan to buzz. Not surprising I suppose as it is bound to be a switching device. Well, the result is crap and doesn't sound good for the fan either.
Anyone know of a voltage dropping fan speed controller that will fit in a single backbox ?
Or a non-continuous voltage dropper that can turn the fan down in steps. Although I might decide I like a bit of noise to mask to "other" noises !
Cheers,
Simon.

sm_jamieson wrote:
OK, at last fitted the fan speed controller for the downstairs loo, and it causes the fan to buzz. Not surprising I suppose as it is bound to be a switching device. Well, the result is crap and doesn't sound good for the fan either.
Anyone know of a voltage dropping fan speed controller that will fit in a single backbox ?
Or a non-continuous voltage dropper that can turn the fan down in steps. Although I might decide I like a bit of noise to mask to "other" noises !
Cheers,
Simon.

Experiment with mains voltage rated, Non-electrolytic capacitors to give
the speeds you want.

On Sat, 15 Feb 2014 04:04:56 -0800, sm_jamieson wrote:

OK, at last fitted the fan speed controller for the downstairs loo, and
it causes the fan to buzz. Not surprising I suppose as it is bound to be
a switching device. Well, the result is crap and doesn't sound good for
the fan either.
Anyone know of a voltage dropping fan speed controller that will fit in
a single backbox ?
Or a non-continuous voltage dropper that can turn the fan down in steps.
Although I might decide I like a bit of noise to mask to "other" noises
!
Cheers,
Simon.

I have a couple of S&P ones which don't buzz.

Think they are this one:

http://www.tlc-direct.co.uk/Products/SLREB1.html

HTH

Dave R

On Saturday, February 15, 2014 1:58:23 PM UTC, David.WE.Roberts wrote:
On Sat, 15 Feb 2014 04:04:56 -0800, sm_jamieson wrote:



OK, at last fitted the fan speed controller for the downstairs loo, and

it causes the fan to buzz. Not surprising I suppose as it is bound to be

a switching device. Well, the result is crap and doesn't sound good for

the fan either.

Anyone know of a voltage dropping fan speed controller that will fit in

a single backbox ?

Or a non-continuous voltage dropper that can turn the fan down in steps.

Although I might decide I like a bit of noise to mask to "other" noises

!

Cheers,

Simon.



I have a couple of S&P ones which don't buzz.



Think they are this one:



http://www.tlc-direct.co.uk/Products/SLREB1.html



HTH



Dave R

That's the one I've got !
It doesn't buzz but it causes the fan to buzz unless it is on full speed.
Since I got a slightly overpowered fan to turn it down and make it even quieter,
the buzzing is no good at all.
I have an S&P fan, so they are designed to be compatible. I think its just the nature of switching fan controllers.
Simon.

On 15 Feb 2014 13:58:23 GMT, "David.WE.Roberts"
wrote:

On Sat, 15 Feb 2014 04:04:56 -0800, sm_jamieson wrote:

OK, at last fitted the fan speed controller for the downstairs loo, and
it causes the fan to buzz. Not surprising I suppose as it is bound to be
a switching device. Well, the result is crap and doesn't sound good for
the fan either.
Anyone know of a voltage dropping fan speed controller that will fit in
a single backbox ?
Or a non-continuous voltage dropper that can turn the fan down in steps.
Although I might decide I like a bit of noise to mask to "other" noises
!
Cheers,
Simon.

I have a couple of S&P ones which don't buzz.

Think they are this one:

http://www.tlc-direct.co.uk/Products/SLREB1.html


Interestingly, the technical manual (pdf) indicates its use with
_induction_ motors (I thought it might be limited to universal ac/dc
motor types only).

I've always known that speed control of induction motors required
both frequency and voltage control to avoid overheating of the rotor
(but that is in the case where you need to maintain the same torque
output from the motor in question).

I suppose the reduced drag from the fan blades modifies the situation
somewhat, allowing simple (effective) voltage control without
commensurate frequency changes to avoid rotor overheating.
--
Regards, J B Good

Johny B Good wrote:
On 15 Feb 2014 13:58:23 GMT,
wrote:

On Sat, 15 Feb 2014 04:04:56 -0800, sm_jamieson wrote:

OK, at last fitted the fan speed controller for the downstairs loo, and
it causes the fan to buzz. Not surprising I suppose as it is bound to be
a switching device. Well, the result is crap and doesn't sound good for
the fan either.
Anyone know of a voltage dropping fan speed controller that will fit in
a single backbox ?
Or a non-continuous voltage dropper that can turn the fan down in steps.
Although I might decide I like a bit of noise to mask to "other" noises
!
Cheers,
Simon.

I have a couple of S&P ones which don't buzz.

Think they are this one:

http://www.tlc-direct.co.uk/Products/SLREB1.html


Interestingly, the technical manual (pdf) indicates its use with
_induction_ motors (I thought it might be limited to universal ac/dc
motor types only).

I've always known that speed control of induction motors required
both frequency and voltage control to avoid overheating of the rotor
(but that is in the case where you need to maintain the same torque
output from the motor in question).

I suppose the reduced drag from the fan blades modifies the situation
somewhat, allowing simple (effective) voltage control without
commensurate frequency changes to avoid rotor overheating.

From the dim and not too reliable past, I understood that the loading
varied as the fan speed cubed. The uk diy fan speed control wiki is very
good and as has been said you should be able to knock up a 3 speed
capacitive unit fairly easily. Most ac fan motors are shaded pole, very
resistive and need only voltage control so switched capacitors are very
satisfactory. The unit you're using is a triac system I guess, these
will tend to rattle if the motor coil is a bit loose on the stampings.

I like to use large capacitive 3 speed US ceiling fans for air stirring
as they are very cheap and run somewhat slower than 50HZ units on the
low setting (more slip?) and are very, very quiet. Yes, supplying 120V
is a pain but you only need a few watts. Obviously your requirement is
different.

In article ,
Bob Minchin writes:
sm_jamieson wrote:
OK, at last fitted the fan speed controller for the downstairs loo, and it causes the fan to buzz. Not surprising I suppose as it is bound to be a switching device. Well, the result is crap and doesn't sound good for the fan either.
Anyone know of a voltage dropping fan speed controller that will fit in a single backbox ?
Or a non-continuous voltage dropper that can turn the fan down in steps. Although I might decide I like a bit of noise to mask to "other" noises !
Cheers,
Simon.

You shouldn't use phase control (dimmer) type speed controllers with
shaded pole motors (unless it was specifically designed to handle this).
The harmonics cause significant eddy current heating in the cores,
combined with reduced cooling due to lower speed.

The sound (buzzing) is due to these harmonics causing some part of the
motor to vibrate.

Experiment with mains voltage rated, Non-electrolytic capacitors to give
the speeds you want.

+1

A series impedance is the way they are slowed (unless they have a
tapped winding for dual speed operation). Don't try slowing it too
much, because again there is the possibility of overheating - the
airflow cooling drops very much faster than the power dissipation.
Above all, if it can be started at the lower speed, make sure there
is still enough starting torque to ensure there's no chance of it
sitting there powered up with a stalled rotor.

If the motor doesn't have an overtemp cutout, you might consider
adding one whilst you are doing this. I do so when reconditioning
some types of fan.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

On Sat, 15 Feb 2014 07:41:48 -0800, sm_jamieson wrote:

On Saturday, February 15, 2014 1:58:23 PM UTC, David.WE.Roberts wrote:
On Sat, 15 Feb 2014 04:04:56 -0800, sm_jamieson wrote:



OK, at last fitted the fan speed controller for the downstairs loo,
and

it causes the fan to buzz. Not surprising I suppose as it is bound to
be

a switching device. Well, the result is crap and doesn't sound good
for

the fan either.

Anyone know of a voltage dropping fan speed controller that will fit
in

a single backbox ?

Or a non-continuous voltage dropper that can turn the fan down in
steps.

Although I might decide I like a bit of noise to mask to "other"
noises

!

Cheers,

Simon.



I have a couple of S&P ones which don't buzz.



Think they are this one:



http://www.tlc-direct.co.uk/Products/SLREB1.html



HTH



Dave R

That's the one I've got !
It doesn't buzz but it causes the fan to buzz unless it is on full
speed.
Since I got a slightly overpowered fan to turn it down and make it even
quieter,
the buzzing is no good at all.
I have an S&P fan, so they are designed to be compatible. I think its
just the nature of switching fan controllers.
Simon.

Are these in line extractor fans for bathrooms/kitchens?

The ones we have are like bloody great rugby balls and fit in the ceiling
void.

Haven't noticed any buzz - in fact the non-speed-controlled one in the
loft is virtually silent and the noise comes from the air intake in the
bathroom.

Cheers

Dave R

On Saturday, February 15, 2014 7:43:37 PM UTC, David.WE.Roberts wrote:

That's the one I've got !

It doesn't buzz but it causes the fan to buzz unless it is on full

speed.

Since I got a slightly overpowered fan to turn it down and make it even

quieter,

the buzzing is no good at all.

I have an S&P fan, so they are designed to be compatible. I think its

just the nature of switching fan controllers.

Simon.



Are these in line extractor fans for bathrooms/kitchens?



The ones we have are like bloody great rugby balls and fit in the ceiling

void.



Haven't noticed any buzz - in fact the non-speed-controlled one in the

loft is virtually silent and the noise comes from the air intake in the

bathroom.



Cheers



Dave R

Its one of these:
http://www.tlc-direct.co.uk/Products/SLTD250SILENT.html
Simon.

On Saturday, February 15, 2014 12:04:56 PM UTC, sm_jamieson wrote:


OK, at last fitted the fan speed controller for the downstairs loo, and it causes the fan to buzz. Not surprising I suppose as it is bound to be a switching device. Well, the result is crap and doesn't sound good for the fan either.
Anyone know of a voltage dropping fan speed controller that will fit in a single backbox ?
Or a non-continuous voltage dropper that can turn the fan down in steps. Although I might decide I like a bit of noise to mask to "other" noises !

Series capacitor. Dont guess, calculate.


NT

In article ,
Capitol writes:
From the dim and not too reliable past, I understood that the loading
varied as the fan speed cubed. The uk diy fan speed control wiki is very
good and as has been said you should be able to knock up a 3 speed
capacitive unit fairly easily. Most ac fan motors are shaded pole, very

Small ones, anyway. Shaded pole motors are generally limited to
around 50W max (at which point you should change to a more efficient
motor design).

resistive and need only voltage control so switched capacitors are very
satisfactory. The unit you're using is a triac system I guess, these
will tend to rattle if the motor coil is a bit loose on the stampings.

I like to use large capacitive 3 speed US ceiling fans for air stirring
as they are very cheap and run somewhat slower than 50HZ units on the
low setting (more slip?) and are very, very quiet. Yes, supplying 120V

They use an induction motor design with very many poles.
Some have a choice of windings which alternatively combines or
spilts ajacent poles to change the effective number of poles,
but I think most of the speed control is done with capacitor
switching to under-power the motor and generate excessive slip,
which works because the torque required also drops dramatically
as the speed drops.

The motors are a kind of inverted design compared with more
conventional induction motors, with the stationary stator in the
middle, and the armature/rotor around the outside of it, so that
it's the outside of the motor which goes round as the centre is
fixed to the mounting, and can pass wires through for stationary
lights underneath.

There's a series on one of the freeview channels about how things
are made, and one of the issues covered how these motors are made.

is a pain but you only need a few watts. Obviously your requirement is
different.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

On Sat, 15 Feb 2014 12:24:21 -0800, sm_jamieson wrote:

On Saturday, February 15, 2014 7:43:37 PM UTC, David.WE.Roberts wrote:

That's the one I've got !

It doesn't buzz but it causes the fan to buzz unless it is on full

speed.

Since I got a slightly overpowered fan to turn it down and make it
even

quieter,

the buzzing is no good at all.

I have an S&P fan, so they are designed to be compatible. I think its

just the nature of switching fan controllers.

Simon.

Are these in line extractor fans for bathrooms/kitchens?

The ones we have are like bloody great rugby balls and fit in the
ceiling

void.

Haven't noticed any buzz - in fact the non-speed-controlled one in the

loft is virtually silent and the noise comes from the air intake in the

bathroom.


Its one of these:
http://www.tlc-direct.co.uk/Products/SLTD250SILENT.html Simon.

Looks the same as the ones we have.

So I am baffled because we seem to have the same setup but not the same
problem.

Only other thing I can think of is that our fans are located so we can't
hear the buzz!

They do hum - perhaps we are hearing the same thing but perceiving it
differently?

Cheers

Dave R

On Sunday, February 16, 2014 9:14:17 PM UTC, David.WE.Roberts wrote:
On Sat, 15 Feb 2014 12:24:21 -0800, sm_jamieson wrote:
On Saturday, February 15, 2014 7:43:37 PM UTC, David.WE.Roberts wrote:
That's the one I've got !
It doesn't buzz but it causes the fan to buzz unless it is on full
speed.
Since I got a slightly overpowered fan to turn it down and make it
even
quieter,
the buzzing is no good at all.
I have an S&P fan, so they are designed to be compatible. I think its
just the nature of switching fan controllers.
Simon.
Are these in line extractor fans for bathrooms/kitchens?
The ones we have are like bloody great rugby balls and fit in the
ceiling
void.
Haven't noticed any buzz - in fact the non-speed-controlled one in the
loft is virtually silent and the noise comes from the air intake in the
bathroom.
Its one of these:
http://www.tlc-direct.co.uk/Products/SLTD250SILENT.html Simon.
Looks the same as the ones we have.
So I am baffled because we seem to have the same setup but not the same
problem.
Only other thing I can think of is that our fans are located so we can't
hear the buzz!
They do hum - perhaps we are hearing the same thing but perceiving it
differently?
Cheers
Dave R

http://wiki.diyfaq.org.uk/index.php?...oise_reduction


NT

On Sunday, February 16, 2014 9:14:17 PM UTC, David.WE.Roberts wrote:
On Sat, 15 Feb 2014 12:24:21 -0800, sm_jamieson wrote:



On Saturday, February 15, 2014 7:43:37 PM UTC, David.WE.Roberts wrote:



That's the one I've got !



It doesn't buzz but it causes the fan to buzz unless it is on full



speed.



Since I got a slightly overpowered fan to turn it down and make it

even



quieter,



the buzzing is no good at all.



I have an S&P fan, so they are designed to be compatible. I think its



just the nature of switching fan controllers.



Simon.



Are these in line extractor fans for bathrooms/kitchens?



The ones we have are like bloody great rugby balls and fit in the

ceiling



void.



Haven't noticed any buzz - in fact the non-speed-controlled one in the



loft is virtually silent and the noise comes from the air intake in the



bathroom.





Its one of these:

http://www.tlc-direct.co.uk/Products/SLTD250SILENT.html Simon.



Looks the same as the ones we have.



So I am baffled because we seem to have the same setup but not the same

problem.



Only other thing I can think of is that our fans are located so we can't

hear the buzz!



They do hum - perhaps we are hearing the same thing but perceiving it

differently?



Cheers



Dave R

Well its a known effect of triac type controllers that send the fan a chopped up waveform. I'd describe it as a hum/buzz and probably more like a hum to you if its above the ceiling.
Anyway, the point is, does the fan motor noise increase when then controller is turned down from maximum ? At full power all I can hear is air noise.
Anyway it looks like capacitor voltage droppers is the answer so I shall use the wiki procedure to sort it out - when I eventually get a round tuit.
Simon.