Is this a ceiling fan or a stand alone fan?
The simplest is probably a light bulb in series. The lower the wattage,
It is a desktop fan that runs from a 240volt mains supply.
---
Or chop every other blade off the fanOn 13 May 2004 23:40:22 -0700, df.oreilly@btopenworld.com (D O'Reilly)
wrote:
I have an electric fan in my bedroom when even on its slowest setting
is far too
powerful,can anyone tell me how to adjust the fan with some sort of
device or switch to lower the rpm's,your help would be most
appreciated.
---
Connect the fan to the mains through a zero-crossing solid state
relay.
Use an optoisolator as a zero-crossing detector across the mains,
divide its output by two to get nice sharp edges, and use the output
of the divide-by-two to gate a counter.
Shine an IRLED through the fan blades and place an IR phototransistor
in the beam on the other side so that when the fan is rotating it
chops up the beam and turns the phototransistor on and off.
Use the output of the phototransistor to clock the counter which is
being gated by the divide-by-two.
Connect the counter's Q outputs to the inputs of D type flip-flops,
and use one of the divide-by-two's edges to simultaneously clock the
accumulated count into the D flops and clear the counter.
Connect the "A" set of data inputs of a magnitude comparator to the
outputs of the D flops and the "B" set of data inputs to the outputs
of a manually operated binary coded switch.
Connect the B>A output of the magnitude comparator to the control
input of the solid state relay.
Turn on the fan and adjust its speed by changing the setting of the
binary coded switch.
Or use a ľC...
--
John Fields
---"John Fields" <jfields@austininstruments.com> wrote in message
news:2igca0lp7evb0vg2rkqlqmd3peqsdqpl4e@4ax.com...
On 13 May 2004 23:40:22 -0700, df.oreilly@btopenworld.com (D O'Reilly)
wrote:
I have an electric fan in my bedroom when even on its slowest setting
is far too
powerful,can anyone tell me how to adjust the fan with some sort of
device or switch to lower the rpm's,your help would be most
appreciated.
---
Connect the fan to the mains through a zero-crossing solid state
relay.
Use an optoisolator as a zero-crossing detector across the mains,
divide its output by two to get nice sharp edges, and use the output
of the divide-by-two to gate a counter.
Shine an IRLED through the fan blades and place an IR phototransistor
in the beam on the other side so that when the fan is rotating it
chops up the beam and turns the phototransistor on and off.
Use the output of the phototransistor to clock the counter which is
being gated by the divide-by-two.
Connect the counter's Q outputs to the inputs of D type flip-flops,
and use one of the divide-by-two's edges to simultaneously clock the
accumulated count into the D flops and clear the counter.
Connect the "A" set of data inputs of a magnitude comparator to the
outputs of the D flops and the "B" set of data inputs to the outputs
of a manually operated binary coded switch.
Connect the B>A output of the magnitude comparator to the control
input of the solid state relay.
Turn on the fan and adjust its speed by changing the setting of the
binary coded switch.
Or use a ľC...
--
John Fields
Or chop every other blade off the fan
I could agree with that, pretty grossOn Sat, 15 May 2004 20:07:54 +0100, "Mjolinor" <mjolinor@hotmail.com
wrote:
"John Fields" <jfields@austininstruments.com> wrote in message
news:2igca0lp7evb0vg2rkqlqmd3peqsdqpl4e@4ax.com...
On 13 May 2004 23:40:22 -0700, df.oreilly@btopenworld.com (D O'Reilly)
wrote:
I have an electric fan in my bedroom when even on its slowest setting
is far too
powerful,can anyone tell me how to adjust the fan with some sort of
device or switch to lower the rpm's,your help would be most
appreciated.
---
Connect the fan to the mains through a zero-crossing solid state
relay.
Use an optoisolator as a zero-crossing detector across the mains,
divide its output by two to get nice sharp edges, and use the output
of the divide-by-two to gate a counter.
Shine an IRLED through the fan blades and place an IR phototransistor
in the beam on the other side so that when the fan is rotating it
chops up the beam and turns the phototransistor on and off.
Use the output of the phototransistor to clock the counter which is
being gated by the divide-by-two.
Connect the counter's Q outputs to the inputs of D type flip-flops,
and use one of the divide-by-two's edges to simultaneously clock the
accumulated count into the D flops and clear the counter.
Connect the "A" set of data inputs of a magnitude comparator to the
outputs of the D flops and the "B" set of data inputs to the outputs
of a manually operated binary coded switch.
Connect the B>A output of the magnitude comparator to the control
input of the solid state relay.
Turn on the fan and adjust its speed by changing the setting of the
binary coded switch.
Or use a ľC...
--
John Fields
Or chop every other blade off the fan
---
Gross...
An odd number of blades will make the fan vibrate right off the table.
Schematic at abse...
Enjoy!
--
John Fields
statically and dynamically have a balanced blade if you remove an odd number"John Fields" <jfields@austininstruments.com> wrote in message
news:1f6da05urlrkibjqtktkcp6faj4v37t0j4@4ax.com...
On Sat, 15 May 2004 20:07:54 +0100, "Mjolinor" <mjolinor@hotmail.com
wrote:
"John Fields" <jfields@austininstruments.com> wrote in message
news:2igca0lp7evb0vg2rkqlqmd3peqsdqpl4e@4ax.com...
On 13 May 2004 23:40:22 -0700, df.oreilly@btopenworld.com (D
O'Reilly)
wrote:
I have an electric fan in my bedroom when even on its slowest
setting
is far too
powerful,can anyone tell me how to adjust the fan with some sort of
device or switch to lower the rpm's,your help would be most
appreciated.
---
Connect the fan to the mains through a zero-crossing solid state
relay.
Use an optoisolator as a zero-crossing detector across the mains,
divide its output by two to get nice sharp edges, and use the output
of the divide-by-two to gate a counter.
Shine an IRLED through the fan blades and place an IR phototransistor
in the beam on the other side so that when the fan is rotating it
chops up the beam and turns the phototransistor on and off.
Use the output of the phototransistor to clock the counter which is
being gated by the divide-by-two.
Connect the counter's Q outputs to the inputs of D type flip-flops,
and use one of the divide-by-two's edges to simultaneously clock the
accumulated count into the D flops and clear the counter.
Connect the "A" set of data inputs of a magnitude comparator to the
outputs of the D flops and the "B" set of data inputs to the outputs
of a manually operated binary coded switch.
Connect the B>A output of the magnitude comparator to the control
input of the solid state relay.
Turn on the fan and adjust its speed by changing the setting of the
binary coded switch.
Or use a ľC...
--
John Fields
Or chop every other blade off the fan
---
Gross...
An odd number of blades will make the fan vibrate right off the table.
Schematic at abse...
Enjoy!
--
John Fields
I could agree with that, pretty gross
I think that with careful selection of blades it should still be possible to