----- 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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