Hello.....
I was just at Home Depot trying looking for a quick fix
to a problem.
I need to slow down an AC fan motor (measured at 2.3 A full
speed/ 120V.) I was finding all ceiling fan controls are rated at
1.5 A. max. But then I found in the back some other lighting
controllers that were unusual. One was for low-voltage magnetic
and the other electronic transformer types. It connects to the AC
mains, and the magnetic load is downstream.
It seems to me that this controller rated at 5 A. might fit the bill.
Since the inductance/reactance is designed into device, why couldn't
it work....? The motor type...don't know. However, it doesn't
use a starting cap.
Comments please......Thank you.

Les

"les" wrote in message
...
Hello.....
I was just at Home Depot trying looking for a quick fix
to a problem.
I need to slow down an AC fan motor (measured at 2.3 A full
speed/ 120V.) I was finding all ceiling fan controls are rated at
1.5 A. max. But then I found in the back some other lighting
controllers that were unusual. One was for low-voltage magnetic
and the other electronic transformer types. It connects to the AC
mains, and the magnetic load is downstream.
It seems to me that this controller rated at 5 A. might fit the bill.
Since the inductance/reactance is designed into device, why couldn't
it work....? The motor type...don't know. However, it doesn't
use a starting cap.
Comments please......Thank you.

My comments ... triac phase angle control circuits are good with resistive
loads but not good with most motors ... unless they are
brush/commutaor-types, or so-called universal motors. Fan motors are seldom
brush types.

les wrote:

Hello.....
I was just at Home Depot trying looking for a quick fix
to a problem.
I need to slow down an AC fan motor (measured at 2.3 A full
speed/ 120V.) I was finding all ceiling fan controls are rated at
1.5 A. max. But then I found in the back some other lighting
controllers that were unusual. One was for low-voltage magnetic
and the other electronic transformer types. It connects to the AC
mains, and the magnetic load is downstream.
It seems to me that this controller rated at 5 A. might fit the bill.
Since the inductance/reactance is designed into device, why couldn't
it work....? The motor type...don't know. However, it doesn't
use a starting cap.
Comments please......Thank you.

Les


back in the old days, ( and we still have one machine running like this
at work) you would have a wound rotor motor where you control the torque
of the motor via the 3 slip rings and variable rheostats.
with the load on the motor, you simply adjusted this rotor to adjust
how much load torque the motor had. This in turn adjust your speed.

Now, I'm sure you don't have a wound rotor motor there!


--
"I'm never wrong, once i thought i was, but was mistaken"
Real Programmers Do things like this.
http://webpages.charter.net/jamie_5

Okay...
Well then what method is used in the commercially made
home variety "ceiling fan" wall switch?
Triacs are used for incandescents (right?).
What's in those other controllers?
I know PWM would be ideal, but we are talking pedestrian
ceiling fans.
And the windings in my case are on the motor casing.

Les

On Sep 3, 6:51 pm, "les" wrote:
Hello.....
I was just at Home Depot trying looking for a quick fix
to a problem.
I need to slow down an AC fan motor (measured at 2.3 A full
speed/ 120V.) I was finding all ceiling fan controls are rated at
1.5 A. max. But then I found in the back some other lighting
controllers that were unusual. One was for low-voltage magnetic
and the other electronic transformer types. It connects to the AC
mains, and the magnetic load is downstream.
It seems to me that this controller rated at 5 A. might fit the bill.
Since the inductance/reactance is designed into device, why couldn't
it work....? The motor type...don't know. However, it doesn't
use a starting cap.
Comments please......Thank you.

Les

REFER TO OHM'S LAW TO DO CHECKES ON YOUR VOLTAGE AND RESISTANCE AND
AMPS, MOTORS WILL SAFELY OPERATE AT 10% +/- OF THERE SPECS.
( ELECTRONICS +/- 5% )

"les" wrote in message
...
Hello.....
I was just at Home Depot trying looking for a quick fix
to a problem.
I need to slow down an AC fan motor (measured at 2.3 A full
speed/ 120V.) I was finding all ceiling fan controls are rated at
1.5 A. max. But then I found in the back some other lighting
controllers that were unusual. One was for low-voltage magnetic
and the other electronic transformer types. It connects to the AC
mains, and the magnetic load is downstream.
It seems to me that this controller rated at 5 A. might fit the bill.
Since the inductance/reactance is designed into device, why couldn't
it work....? The motor type...don't know. However, it doesn't
use a starting cap.
Comments please......Thank you.

Les




This will usually work for shaded pole motors. If the dimmer is meant for
resistive loads you may have to modify it for it to work with an inductive
load. I saw a link somewhere for modifying a dimmer to control a neon
transformer, that would probably work.

"James Sweet" wrote in message
news:WT5Di.6596$2N2.2556@trndny03...

"les" wrote in message
...
Hello.....
I was just at Home Depot trying looking for a quick fix
to a problem.
I need to slow down an AC fan motor (measured at 2.3 A full
speed/ 120V.) I was finding all ceiling fan controls are rated at
1.5 A. max. But then I found in the back some other lighting
controllers that were unusual. One was for low-voltage magnetic
and the other electronic transformer types. It connects to the AC
mains, and the magnetic load is downstream.
It seems to me that this controller rated at 5 A. might fit the bill.
Since the inductance/reactance is designed into device, why couldn't
it work....? The motor type...don't know. However, it doesn't
use a starting cap.
Comments please......Thank you.

Les




This will usually work for shaded pole motors. If the dimmer is meant for
resistive loads you may have to modify it for it to work with an inductive
load. I saw a link somewhere for modifying a dimmer to control a neon
transformer, that would probably work.

Given that one of the controllers in question is for low voltage lighting
that uses transformer reduction, rather than the switch mode "transformers"
that a lot of this lighting uses when the loading goes up much above about 3
lamps, then you would expect that that particular controller was designed to
handle an inductive rather than resistive load - yes ? If the controller in
question is not too expensive, I think that I would be inclined to 'just
give it a go'.

Arfa

This is what I was thinking, but I'm wondering if the reduced fan speed,
hence
reduced air circulation thru the windings could create overheating in the
windings. The cost of the motor is multifold vs, the switch cost. I want to
avoid
taking actions that seem totally absurd. I wanted to see if the brilliant
people here have any arguments to poke holes in my logic.......
Besides, I'm still curioius about the method used in fan controllers.

Les

Given that one of the controllers in question is for low voltage lighting
that uses transformer reduction, rather than the switch mode
"transformers"
that a lot of this lighting uses when the loading goes up much above about
3
lamps, then you would expect that that particular controller was designed
to
handle an inductive rather than resistive load - yes ? If the controller
in
question is not too expensive, I think that I would be inclined to 'just
give it a go'.

Arfa

"Charles" writes:

"les" wrote in message
...
Hello.....
I was just at Home Depot trying looking for a quick fix
to a problem.
I need to slow down an AC fan motor (measured at 2.3 A full
speed/ 120V.) I was finding all ceiling fan controls are rated at
1.5 A. max. But then I found in the back some other lighting
controllers that were unusual. One was for low-voltage magnetic
and the other electronic transformer types. It connects to the AC
mains, and the magnetic load is downstream.
It seems to me that this controller rated at 5 A. might fit the bill.
Since the inductance/reactance is designed into device, why couldn't
it work....? The motor type...don't know. However, it doesn't
use a starting cap.
Comments please......Thank you.

My comments ... triac phase angle control circuits are good with resistive
loads but not good with most motors ... unless they are
brush/commutaor-types, or so-called universal motors. Fan motors are seldom
brush types.

You may get away with it for shaded pole induction motors, which are
what many smaller fans use. Just be aware you may blow the dimmer
but probably won't damage the motor.

I use a small Variac for my large recycled computer fan. That works very
well.

--- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
+Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
| Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html

Important: Anything sent to the email address in the message header above is
ignored unless my full name AND either lasers or electronics is included in the
subject line. Or, you can contact me via the Feedback Form in the FAQs.

les writes:

Comments please......Thank you.

I use a variable autotransformer (Variac) on my shop fan.

Richard J Kinch writes:

les writes:

Comments please......Thank you.

I use a variable autotransformer (Variac) on my shop fan.

I agree. Except for the possibility of overheating due to reduced air
flow - which is easy to check - this is the safest.

--- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
+Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
| Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html

Important: Anything sent to the email address in the message header above is
ignored unless my full name AND either lasers or electronics is included in the
subject line. Or, you can contact me via the Feedback Form in the FAQs.

"les" wrote in message
...
This is what I was thinking, but I'm wondering if the reduced fan speed,
hence
reduced air circulation thru the windings could create overheating in the
windings. The cost of the motor is multifold vs, the switch cost. I want
to
avoid
taking actions that seem totally absurd. I wanted to see if the brilliant
people here have any arguments to poke holes in my logic.......
Besides, I'm still curioius about the method used in fan controllers.

Les



Lower motor power with a load that lessens with RPM such as a fan means less
heat in the windings, so it should all even out. If in doubt, check the
motor temp with your calibrated finger and compare it to full speed.

"James Sweet" wrote in message
news:CerDi.6502$NL2.1205@trndny04...

"les" wrote in message
...
This is what I was thinking, but I'm wondering if the reduced fan speed,
hence
reduced air circulation thru the windings could create overheating in the
windings. The cost of the motor is multifold vs, the switch cost. I want
to
avoid
taking actions that seem totally absurd. I wanted to see if the brilliant
people here have any arguments to poke holes in my logic.......
Besides, I'm still curioius about the method used in fan controllers.

Les



Lower motor power with a load that lessens with RPM such as a fan means
less heat in the windings, so it should all even out. If in doubt, check
the motor temp with your calibrated finger and compare it to full speed.

That's a cracking bit of 'thinking outside the box', James !! I bet it
wasn't early morning when you came up with that one ! Well, it wouldn't have
been for me, anyway ... d;~}

Arfa

On Mon, 3 Sep 2007 17:51:01 -0500, "les" wrote:

Hello.....
I was just at Home Depot trying looking for a quick fix
to a problem.
I need to slow down an AC fan motor (measured at 2.3 A full
speed/ 120V.) I was finding all ceiling fan controls are rated at
1.5 A. max. But then I found in the back some other lighting
controllers that were unusual. One was for low-voltage magnetic
and the other electronic transformer types. It connects to the AC
mains, and the magnetic load is downstream.
It seems to me that this controller rated at 5 A. might fit the bill.
Since the inductance/reactance is designed into device, why couldn't
it work....? The motor type...don't know. However, it doesn't
use a starting cap.
Comments please......Thank you.

Les

It's been my experience that it will work with shaded pole motors and
very small split phase induction motors and work with fans since it
greatly cuts down starting torque and fans don't require a lot of
starting torque.

Try it. Downside is it may buzz and run warmer since you are
introducing more slip - and if the objective was to save money it
probably won't do that.

If you put an ammeter on it . . . as you tweak down the voltage the
current will start to drop as well until it reaches ~100 volts then
the current shoots UP disproportionately with respect to the reduction
in voltage.

I employed a schematic from one of the "encyclopedia's of electronic
circuits" that was very similar to a lamp dimmer but had feedback to
maintain a constant voltage - the stated purpose was to keep a movie
projector's lamp at a constant voltage. The fan I used it on was a
belt driven 26" with a 4 amp motor (I believe it was split capacitor).
I just adjusted the voltage down until the current started to rise -
just to save a little money - a sort of poor man's power factor
controller. That worked very well and the motor ran cooler.
--

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