----- Original Message -----
Sent: Tuesday, February 07, 2006 4:44
PM
Subject: Re: [PSUBS-MAILIST] link
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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