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Topic: Router speed controller results (12 msgs / 240 lines)
1) From: Ken Mary
My router controller checked out with a bad triac, one half of the cycle 
showing near zero voltage on the scope. Its behavior did not change from the
first test on a Poppery fan last Fall. This is a replacement unit, the first
was returned with the same problem. I told MLCS they may have many defective
units and to check out my replacement before mailing it. I gave up on
returning it and getting any satisfactory response from MLCS.
The circuitry shows it is nothing more than a dimmer with a suitable triac
to handle the rated 15 amp current.
I also scoped Lutron and GE incandescent dimmers with interesting (to me
anyway) results. Both showed the full cycle with distinct chops in the
"rising" part of each half cycle. But here is the important part, the GE
dimmer at max showed the chop nearly closed, but the Lutron still chopped
for a large part of the half cycle. This means that the GE would be the
better dimmer to use for controlling fan speed, enabling full speed at the
max setting. The Lutron would not give full fan speed. I am now going to
replace my Lutron with the GE (cheap at Walmart).
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2) From: Mike McGinness
From: "Ken Mary" 
 I also scoped Lutron and GE incandescent dimmers with interesting (to
me
<Snip>
Which means if I'd gotten a cheap GE instead of Lutron I probably would not
of needed the 25.2v transformer for boost. No biggy since the 12.6v 3A and
25.2v 2A were the same cost. But, it also means that if I pull out the
Lutron and put in a GE I'll be able to boost my usable fan voltage beyond my
current 139v! Which maybe isn't a good idea, will contemplate. Though in the
spirit of Tim the Tool Man Taylor MORE POWER:-) I went with the Lutron fan
control unit even though it cost more because 1) it was designed for AC
ceiling fan control not for lights and 2) it was rated 5A loads. Now it
sounds like a $4-$5 light dimmer would work fine too instead of $10 ceiling
fan controller.
MM;-) aka Kona Konnaisseur miKe mcKoffee
Dual Variable Transformer Rosto Roasting
Rocky grindin' - Miss Silvia brewin'
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3) From: Ben Treichel
Do they build non solid state dimmers any more? I can't find a multi 
-watt pot. I havn't looked that hard, was hoping to find it at wally 
mart of radio shi....
Mike McGinness wrote:
<Snip>

4) From: dewardh
Ken:
<Snip>
showing near zero voltage on the scope.
That was what it sounded like, and is the "normal" failure mode (from "thermal" 
overload).
<Snip>
to handle the rated 15 amp current.
It . . . annoys . . . me when they do that . . . marketing instead of 
engineering.  There should at least be some additional filtering to protect the 
triac from brush noise and voltage spikes (that can occur with motors, but 
don't happen with lights).  If they're not going to put the additional 
protection in the box they should just call it a dimmer.  The other thing they 
*may* change is the taper on the control pot, to get more uniform motor speed 
change.  But what you say makes it sound as if they might well skip that, too.
<Snip>
anyway) results. Both showed the full cycle with distinct chops in the
"rising" part of each half cycle. But here is the important part, the GE
dimmer at max showed the chop nearly closed, but the Lutron still chopped
for a large part of the half cycle. This means that the GE would be the
better dimmer to use for controlling fan speed, enabling full speed at the
max setting. The Lutron would not give full fan speed. I am now going to
replace my Lutron with the GE (cheap at Walmart).
I wonder why they do that . . . (use different turn-on thresholds).  If it's 
consistent across samples it must be a "design decision" that has a reason 
behind it.  One obvious reason is reliability, of course . . . another would be 
to avoid heat buildup from continuous "on" operation.  That initial "on" time 
adds just a little to the light output, but does increase the heat dissipation 
in the dimmer.  Does the Lutron device have a "full on" switch position that 
bypasses the dimmer altogether?  Without that *neither* device can give *full* 
fan speed, because of the voltage drop across the triac.
Deward
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5) From: dewardh
<Snip>
Lutron and put in a GE I'll be able to boost my usable fan voltage beyond my
current 139v!
Not.  The peak voltage won't change at all . . . it will be whatever goes in to 
the dimmer, minus the (nearly constant) voltage drop across the triac.  What 
Ken is saying *changes* is that the GE device turns "on" a bit sooner in the 
beginning (low voltage) part of each cycle.
If you want "full on" performance from the fan just add a switch that bypasses 
the dimmer and connects the fan direct to the boost transformer (if the Lutron 
doesn't have that already).  That *will* give "full voltage" (and "full power") 
to the fan.
Deward
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6) From: dewardh
Ben:
<Snip>
-watt pot.
High wattage variable resistors ("pots") are getting real scarce now that there 
are so many better alternatives.  They were never suitable for use as 
"dimmers", though, because they would dim the light by dumping the power as 
heat in the potentiometer . . . not what you want inside your wall .  You'd 
need a 25 Watt dissipation rating to dim a 100 Watt bulb, 150 Watts to match 
the 600 Watt rating of a little solid state dimmer.  Gives a whole new meaning 
to "torchier".
Non solid state dimmers are still available . . . they're called variacs 
(variable voltage autotransformers).  Small sizes are not very common, though. 
 You certainly won't find them at Wall Mart or Radio Shack .
Deward
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7) From: Mike McGinness
From: "dewardh" 
<Snip>
in to
<Snip>
What
<Snip>
the
<Snip>
bypasses
<Snip>
Lutron
<Snip>
power")
<Snip>
When you put it "that way" it makes sense. Like duh, peak of wave is peak of
voltage. Been way to long since AC theory! Thanks for the correction. Don't
think I'll worry about being able to lower the voltage to the fan more:-)
The small gain of by-passing the dimmer via toggle switch doesn't sound
worth the hassle (both of installation and use) not really needed.
MM;-) aka Kona Konnaisseur miKe mcKoffee
Dual Variable Transformer Rosto Roasting
Rocky grindin' - Miss Silvia brewin'
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8) From: Ken Mary
<Snip>
the
<Snip>
There is one capacitor in the router control. Maybe it acts as a signal
filter. There is no output filter. All the cheap dimmers that I have taken
apart have an iron core coil to reduce interference from the dimmer on other
devices. I did not previously mention the additional hype about the
controller "maintaining full motor torque" as the speed is reduced.
<Snip>
I have no explanation for this but it does remind me that the useful
adjustment range from max to "motor almost off" is about 180 degrees. I
wonder if the pot's slope can be changed so that at minimum, you get a fan
speed that is within useable range.
I only have two operating dimmers now but will be buying another GE, so I
can scope its operation also. None of the dimmers I have seen have a full-on
switch, that is why I added one to the Lutron circuit for full fan speed.
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9) From: Ken Mary
<Snip>
to
<Snip>
What I see on the scope on both units is the normal voltage rise to maybe 30
volts, then the flat chopped portion which changes in width with knob
setting, then the normal sine curve resumes. It is the width of the flat
that is almost zero with the GE set at max. The width of the Lutron flat at
max is maybe 30 degrees or a sixth of the half wave. More of the normal
curve means more *current* to the motor. I am not an expert at this, and am
recalling from memory. The scope is put away now, maybe in a few days I will
look again.
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10) From: Rick Farris
Mike wrote:
<Snip>
If all you're boosting is the fan, I don't see any problem with it.  Perhaps
for continuous duty it might be a problem, but for five minutes at a time,
I'll bet you could pump that baby up to, oh, 165VAC.  The first couple of
times I did it, I'd have my smeller in the vicinity of the fan, checking for
ozone and/or the sounds of minor arcing.  If I didn't notice anything I'd
say it was good to go.  If it doesn't arc right off the bat, I would expect
to be able to smell the thing overheating long before it was permanently
damaged.
-- Rick
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11) From: dewardh
Ken:
To get the best "look" at what it's doing have it "loaded" while testing (maybe 
a 100 Watt light bulb).  What happens with just a high impedance scope probe 
connected to the "output" may be quite different . . . (and, of course, with a 
motor load it may be different still . . .).
Deward
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12) From: Ken Mary
<Snip>
Yes it was loaded with a Poppery I fan.
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