No shit. I never said they were, it was your buddies who keep throwing
"shaded pole" into the conversation. I just replied that a shaded pole
motor is indeed an induction motor. Go back and see who first mentioned
shaded pole motors. It wasn't me.
On Jul 12, 11:20 pm, " firstname.lastname@example.org"
$39 is not too bad I dont think, I use the 10 amp one at the bottom of
this page (my fan only draws 5 amps but I wanted the controller to run
real cool so I oversized it): I got this same model for about $25
On Jul 14, 7:21 pm, " email@example.com"
Well It's been working great for 3 years now, and it runs cool, the
heat sink on the 10 amp controller barely gets warm powering a 4 amp
Here is the wording from their web site (note it says ok for fans):
"The KBWC-110K provides infinitely variable speed motor control for
Shaded Pole, Permanent Split Capacitor and Universal (AC/DC) motors.
The variable speed motor control contains the following features; an
on/off line switch, RFI filter, minimum speed trimpot and a flame-
retardant ABS enclosure. Applications include range hoods, vibrators,
humidifiers, fireplace blowers, fans, laminar flow hoods, heat tunnels
My fan has a 2 speed motor. The 2 speeds are from separate windings -
each speed has a different number of poles in the motor.
You can easily control a "universal" motor - the type with brushes. Not
likely that is what is in the fan.
Three phase motors can be controlled by changing the frequency. No
possibility there is a 3 phase motor in the fan. The control would be
relatively expensive. I have never seen info, but I suspect the new
variable speed furnace motors are of this basically this type.
You could probably use a variable frequency control for a standard
induction motor, but if the speed falls to where the start switch in the
motor turns on you will probably burn out the motor. And probably
If you use a "phase angle" controller, like a light dimmer, you could
control the speed - the motor speed falls farther from the "rotating
field" speed. Has the same problem with start switches. I believe the
torque falls rapidly as the speed drops, but the power required for a
fan, if I remember right, is about the 4th power of the RPM.
Briefly looking at the info for one of the speed controllers, it says it
is for shaded pole motors (which are used in clocks and my bathroom fan)
and permanent split capacitor motors, which is not likely what is
being used for the fan. Not obvious from what I saw that the 10A speed
control would work for a typical induction motor, which is probably what
powers the fan. These controls are probably "phase angle" controllers -
Outside of a 2 (or more speed) induction motor, I don't know how you
reliably control the speed of an induction motor that probably powers
the fan. How does the control work? How do you avoid problems with the
Uh... hello? A shaded pole motor IS an induction motor. Motor speed
controllers will vary their speed by varying the frequency. Try google.
You will not find a shaded pole motor on a fan of any size - like a
"whole house" fan that makes too much noise.
The motor controller I commented on (from your previous post) is almost
certainly a "phase angle" control (like a light dimmer). It does not
change the frequency.
The controller I looked at was also stated to work with a permanent
split capacitor motor. If I remember right, they are a 2 winding motor
with a capacitor in series with one of the windings. There is no start
cap and no start switch. It is basically a 2-phase motor. (I don't
remember ever seeing one.)
Neither of the motors that the controller said it was good for has a
start switch. A "whole house" fan will almost certainly have an
induction motor with a start switch. Using a dimmer-type control, as
above, can easily burn out the motor. It is a misapplication according
to the limited information provided with the control.
What is it like to guess instead of going by the facts? Probably
everything goes your way, if you don't read the specs.
There is a lot more info out there. I can't do all the work for you,
look up KB Electronics and read the specs. And if you look at the
picture, you will see that from the "off" position,the first "on"
position is "high". Yes it will start the motor.
Facts: a variable frequency drive converts the AC line to DC and then
inverts that to variable frequency AC. There is no way the enclosures
have enough space for the filter capacitors that would be required. Also
way to cheap. And all VFDs I have seen are for 3 phase motors.
They are "phase angle" controls.
I read the specs - "shaded pole" or "PSC motors". Neither of these
motors has a start switch. Find me a "whole house" fan that uses either.
Someone else said that shaded pole motors are about 1/4 HP max. In a
fast look at Grainger I only saw 1/5 HP max. Find a "whole house" fan
that only uses a 1/5 HP motor.
If you set the speed too low will the motor start switch close? If it
does the motor is likely toast. The motors in the manufacturer's spec do
not have a start switch. There is a reason.
Where in the specs does it say the control is good for an induction
motor with a start switch that would be used on a "whole house" fan?
Seems to be a lot of people who disagree with you.
I was replying to those who said the speed controls I pointed to would
not work on an induction motor. The specs says it does. That's all. I
didn't argue that they would work for a whole house fan. My grinder is
1/2hp and it has an induction motor.
Here is a 2HP induction motor. There are many more even larger.
Again, the motor speed controllers I posted a link to do work on
induction motors. That is a fact. That's all I'm saying. What did I
post that is not true?
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