Two phase controllers in series?

L

Lostgallifreyan

Guest
Hello. I want to use a phase controller with more control over a drill's AC
motor speed than the controller inside the drill. I'm hoping it's enough to
set the internal one at full speed and to ignore it while using the external
controller. Is this bad, and if so, what can be done to make it safe? I could
bypass the internal circuit but I want to avoid that if possible. If it is
safe to use both, are there special considerations for setting the two
controls?
 
Lostgallifreyan wrote:
Hello. I want to use a phase controller with more control over a drill's AC
motor speed than the controller inside the drill. I'm hoping it's enough to
set the internal one at full speed and to ignore it while using the external
controller. Is this bad, and if so, what can be done to make it safe? I could
bypass the internal circuit but I want to avoid that if possible. If it is
safe to use both, are there special considerations for setting the two
controls?
Well there may be a problem if you already have a
Click to expand...
electronic speed control in side it. If all it has is a
rheostat type speed control then you're all set.

--
"I'd rather have a bottle in front of me than a frontal lobotomy"

http://webpages.charter.net/jamie_5"
 
Jamie <jamie_ka1lpa_not_valid_after_ka1lpa_@charter.net> wrote in
news:HnSmj.126$uZ.1@newsfe05.lga:

Lostgallifreyan wrote:
Hello. I want to use a phase controller with more control over a
drill's AC motor speed than the controller inside the drill. I'm
hoping it's enough to set the internal one at full speed and to ignore
it while using the external controller. Is this bad, and if so, what
can be done to make it safe? I could bypass the internal circuit but I
want to avoid that if possible. If it is safe to use both, are there
special considerations for setting the two controls?

Well there may be a problem if you already have a
electronic speed control in side it. If all it has is a
rheostat type speed control then you're all set.
Click to expand...
It does, that's why I asked about two phase controllers. :) But if it is set
to pass through whatever it sees coming in, would it work as I described it?
This is not something for the usual try-it-and-see approach, not on new
equipmemt with maker's guarantee intact, which is also why I don't want to go
in and bypass stuff.
 
Lostgallifreyan wrote:

Jamie <jamie_ka1lpa_not_valid_after_ka1lpa_@charter.net> wrote in
news:HnSmj.126$uZ.1@newsfe05.lga:


Lostgallifreyan wrote:

Hello. I want to use a phase controller with more control over a
drill's AC motor speed than the controller inside the drill. I'm
hoping it's enough to set the internal one at full speed and to ignore
it while using the external controller. Is this bad, and if so, what
can be done to make it safe? I could bypass the internal circuit but I
want to avoid that if possible. If it is safe to use both, are there
special considerations for setting the two controls?


Well there may be a problem if you already have a
electronic speed control in side it. If all it has is a
rheostat type speed control then you're all set.



It does, that's why I asked about two phase controllers. :) But if it is set
to pass through whatever it sees coming in, would it work as I described it?
This is not something for the usual try-it-and-see approach, not on new
equipmemt with maker's guarantee intact, which is also why I don't want to go
in and bypass stuff.
if it has a rheostat speed control,. you can run a phase control into it
Click to expand...
as is.


--
"I'd rather have a bottle in front of me than a frontal lobotomy"

"Daily Thought:

SOME PEOPLE ARE LIKE SLINKIES. NOT REALLY GOOD FOR ANYTHING BUT
THEY BRING A SMILE TO YOUR FACE WHEN PUSHED DOWN THE STAIRS.
http://webpages.charter.net/jamie_5"
 
Jamie <jamie_ka1lpa_not_valid_after_ka1lpa_@charter.net> wrote in
news:WBSmj.128$uZ.23@newsfe05.lga:

Lostgallifreyan wrote:

Jamie <jamie_ka1lpa_not_valid_after_ka1lpa_@charter.net> wrote in
news:HnSmj.126$uZ.1@newsfe05.lga:


Lostgallifreyan wrote:

Hello. I want to use a phase controller with more control over a
drill's AC motor speed than the controller inside the drill. I'm
hoping it's enough to set the internal one at full speed and to ignore
it while using the external controller. Is this bad, and if so, what
can be done to make it safe? I could bypass the internal circuit but I
want to avoid that if possible. If it is safe to use both, are there
special considerations for setting the two controls?


Well there may be a problem if you already have a
electronic speed control in side it. If all it has is a
rheostat type speed control then you're all set.



It does, that's why I asked about two phase controllers. :) But if it
is set to pass through whatever it sees coming in, would it work as I
described it? This is not something for the usual try-it-and-see
approach, not on new equipmemt with maker's guarantee intact, which is
also why I don't want to go in and bypass stuff.
if it has a rheostat speed control,. you can run a phase control into it
as is.
Click to expand...

Anyone else? That's twice now I mentioned PHASE CONTROLLERS. Two of them.
I'll take any help I can get but I'd prefer it camne from someone who reads
what I say first, it saves me having to say loads more stuff that won't get
read.
 
Lostgallifreyan <no-one@nowhere.net> wrote in
news:Xns9A31F1F52E16Ezoodlewurdle@140.99.99.130:

Hello. I want to use a phase controller with more control over a drill's
AC motor speed than the controller inside the drill. I'm hoping it's
enough to set the internal one at full speed and to ignore it while
using the external controller. Is this bad, and if so, what can be done
to make it safe? I could bypass the internal circuit but I want to avoid
that if possible. If it is safe to use both, are there special
considerations for setting the two controls?
Click to expand...
Anyone? Can't beleive no-one here knows. Bet someone's actually tried it,
too. :)
 
"Lostgallifreyan" wrote...

Anyone? Can't beleive no-one here knows. Bet someone's actually tried it,
too. :)
Click to expand...
No, possibly, and no. I'm not ignoring you, I actually don't know.
 
Cornelius J Rat wrote:

"Lostgallifreyan" wrote...

Anyone? Can't beleive no-one here knows. Bet someone's actually tried
it, too. :)

No, possibly, and no. I'm not ignoring you, I actually don't know.
Click to expand...
FWIW I don't know either. But I will hazard a guess:-

If the internal controller is dead short then an external one would
function in a similar manner to the internal one.

If the internal controller is OC, then there is no point in using an
external one.

If the internal controller functions at all then all bets are off.

HTH
--
Regards:
Baron.
 
Cornelius J Rat wrote:
"Lostgallifreyan" wrote...

Anyone? Can't beleive no-one here knows. Bet someone's actually tried it,
too. :)


No, possibly, and no. I'm not ignoring you, I actually don't know.
Click to expand...
Most of us are probably in the range *between* far to dumb and far too
clever so *wont* try stuff like that unless someone else is payiing the
bill :) I cant imagine that enything good can happen when the upstream
controller is set for narrow phase angle, low power output and the
control circuit down stream is getting insufficient voltage and extreme
dV/dt thrown at it. Best case, its going to drop out somewhere between
half speed and minimum speed, and may require a power cycle to restart
or worst case you let the magic smoke out of one or both controllers.
Apart from being employed by the manufacturer of a commercial external
speed control, doing compatibility testing, I cant imagine getting paid
to find out . . .
If you do experiment with this, PLEASE video it, its gotta be better
than unboxing!

Personally I'd be fitting a switch to the tool to bypass the internal
controller as my educated guess is thats less hassle than fixing the
possible burn-up.



--
Ian Malcolm. London, ENGLAND. (NEWSGROUP REPLY PREFERRED)
ianm[at]the[dash]malcolms[dot]freeserve[dot]co[dot]uk
[at]=@, [dash]=- & [dot]=. *Warning* HTML & >32K emails --> NUL:
 
Baron <baron.nospam@linuxmaniac.nospam.net> wrote in
news:fnq4df$p0n$1@aioe.org:

Cornelius J Rat wrote:


"Lostgallifreyan" wrote...

Anyone? Can't beleive no-one here knows. Bet someone's actually tried
it, too. :)

No, possibly, and no. I'm not ignoring you, I actually don't know.

FWIW I don't know either. But I will hazard a guess:-

If the internal controller is dead short then an external one would
function in a similar manner to the internal one.

If the internal controller is OC, then there is no point in using an
external one.

If the internal controller functions at all then all bets are off.

HTH
Click to expand...
Nice. Got answers. :) Thanks.
I think the same, but also that if the devices are usually made to switch off
at zero crossings and on at whatever point in the cycle is determined by the
controller of the triac I assume is usually used as a switch, then some
waveform with enough energy even at low outputs will be useable if the second
phase controller is efficient at using a supply, but it almost certainly
wasn't designed to take such input...

So long as the first controller is outputting most if not all of the sine
wave half cycles the second will work fine, but in my case I want to know if
the other way round is ok. My guess is it might, assuming that some
capacitance exists for storing the switch control supply and can store enough
even with low duty cycles from the input. The other issue that I'm really
uncertain about is if there might be unusually strong voltage or current
surges that might damage the second phase controller.
 
Ian Malcolm <valid.address.in.signature@invalid.invalid> wrote in
news:fnq506$eo3$1@inews.gazeta.pl:

Most of us are probably in the range *between* far to dumb and far too
clever so *wont* try stuff like that unless someone else is payiing the
bill :)
Click to expand...
Which makes me feel less like a freak cos I wasn't about to try either. :)

I cant imagine that enything good can happen when the upstream
controller is set for narrow phase angle, low power output and the
control circuit down stream is getting insufficient voltage and extreme
dV/dt thrown at it. Best case, its going to drop out somewhere between
half speed and minimum speed, and may require a power cycle to restart
or worst case you let the magic smoke out of one or both controllers.
Apart from being employed by the manufacturer of a commercial external
speed control, doing compatibility testing, I cant imagine getting paid
to find out . . .
Click to expand...
Yes, I think the sharp transients are the Bad Thing waiting to happen. The
idea that enough power gets through to allow the second control system to
work was bearable, but I can't convince myself that those transients will
treat the second controller (in the drill) the way it deserves to be treated.

If you do experiment with this, PLEASE video it, its gotta be better
than unboxing!
Click to expand...
Couldn't do it even if I wanted to, sadly. No video camera...

Personally I'd be fitting a switch to the tool to bypass the internal
controller as my educated guess is thats less hassle than fixing the
possible burn-up.
Click to expand...
Agreed. Some drills actually have a switched setting at the far end of the
pot's turn, to bypass the controller, or provide another switch. This
doesn't, but I think I can manage to fix this without doing anything
noticeable enough to void a guarantee.
 
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