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Hi Ray.
Your e mail confirmed a nagging thought I had about
the operating differences between DC and AC voltage.
I was wondering if the ac and dc voltage would both
work in the dimmer switch, but wasn't sure.
Your e mail confirmed for me that it doesn't. Rats!
Back to square one. So if I don't find a ready
made, available for sale variable speed waterproof
and pressurproof switch, it now appears my only
choice is to make one using those circuit boards in
conjunction with a magnetic proximity switch
and waterproof and pressureproof it by encasing it
in pvc. Ray, how does the pulse wave modulation
broken into duty cycles for a percentage of time
work? Does that mean I could only run it at one
particular speed for just a certain amount of time?
Or does that mean it would work as a variable
speed controller like you know I want across the
entire speed range? I've still got to check on the
manufacturer NP sent me wherein he said they have
ready made exactly what I need. Hope so.
Hate to have to make this switch.
I had some doubts about the ac and dc working in
the dimmer switch but was going to try and
experiment with it anyway, but now you have saved me time and effort by confirming
those doubts.
Thanks for your help and info and saving me from
wasting my time and effort Ray. I'm great with ballast,
hands on forming and a lot of other things, but the
electrics are my weak point.
Bill Akins.
----- Original Message -----
Sent: Tuesday, February 07, 2006 2:35
PM
Subject: Re: [PSUBS-MAILIST] link
Hi Bill,
I believe that household rotary light dimmer
switches
rely on the fact that the voltage is AC. Alternating
between
0VAC and 120VAC as a sine wave. The SCR in the
switch turns on when the
voltage gets to a level set
by the rotary switch then turns off when the
sine wave
peaks and drops below that point.
With a DC circuit you
do not get that automatic
voltage change that the the SCR can trigger on.
The way to control DC is either on/off, or using PWM
where the DC
is electronically broken up into duty
cycles of being on for a percentage
of time and off
the other percentage of
time.
Regards,
Ray
--- Akins <lakins1@tampabay.rr.com>
wrote:
> Thanks again for thinking of me Steve. But it
>
wouldn't help it to stay dry even if it was inside
> my sub. My sub is a
completely wetsub that I use
> scuba gear
> to operate. No dry
cockpit in my boat. It wouldn't
> be practical for me to install it in a
pod outside
> the sub when I need it in the cockpit. It's not
>
locating the electronics
> that is the problem. I can and have found
them at
> many sites. All kinds of circuit boards to operate a
>
DC variable speed motor. Just none of
> them I have found thus far are
already waterproof
> and pressureproof with an exposed to the
water
> switch knob, handle or twistgrip. For my
> application I
don't need a fancy circuit board. I am
> using between the voltage
spectrum of 12 volts for
> half speed and 24 volts for full
speed.
> Since a household rotary light dimmer switch is made
> to
handle 115 volts, it will more than handle my max
> of 24 volts. So you
see I don't
> need a circuit board. If I wanted to make the
switch
> myself, it would be simplest and cheapest to just
> use
the rotary dimmer switch and
> encase it in pvc and use a magnet to
actuate it
> without using a circuit board for the switch at
all.
> The problem is then installing the dimmer
> switch in pvc
to water and pressure proof it and
> then to make a magnet actuate the
shaft to the
> switch. I could probably do it by taking the
>
time and trouble to experiment but it would just be
> so much easier to
be able to buy one like I need. If
> I can find it.
> Bill
Akins.
>
>
> ----- Original Message -----
> From: steve
> To: personal_submersibles@psubs.org
> Sent: Monday, February 06, 2006 6:22
PM
> Subject: RE: [PSUBS-MAILIST] link
>
>
> considering they make them for land vehicles, i'm
>
not suprised!
> surely it would be contained within the sub
or a
> custom pod outside?
>
>
steve
> -----Original
Message-----
> From: owner-personal_submersibles@psubs.org
>
[mailto:owner-personal_submersibles@psubs.org]On
> Behalf Of
Akins
> Sent: 06 February 2006
23:33
> To: personal_submersibles@psubs.org
>
Subject: Re: [PSUBS-MAILIST] link
>
>
> Thanks for the links Steve.
>
> However I didn't see any waterproof
and
> pressureproof variable speed motor controllers ready
> made
at the sites.
> Bill Akins.
>
>
> ----- Original Message -----
> From: steve
> To: personal_submersibles@psubs.org
> Sent: Saturday, February 04, 2006
6:37 PM
> Subject: [PSUBS-MAILIST]
link
>
>
>
> just in case it's
useful to
anyone...
>
> www.4qd.co.uk
>
> make electric vehicle
speed controllers and
> have a sister site www.4qdtec.com with lots of good
>
info.
> pay the small
subscription fee its worth
it!
>
>
steve
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