See Water bilge switch report.
 

Those of you who read my report on my grandiose bilge system know that
I ignored the advice of the capacitance switch builder who said they
couldn't cost less than a grand and work. Well, he was right. This is
a great idea but it's not ready for prime time on most boats.

I set the whole thing up in my basement in a tub about the size of my
bilge sump with the hose let uphill to simulate the run that will go
in the boat.

Other solid state, electronic float switches have a high "On" trigger
point and a lower "Off" trigger. The See Water is instant on when
water touches the probe. Even a splashed drop seems to set it off.
There is no ON time delay at all. The instant the water drops below
the probe, an 8 - 10 second time delay starts. This is to draw the
water down low enough that backflow through the hoses won't set up an
endless cycle that drains the batteries. Unfortunately, the time delay
is totally inadequate for the length of hose run that would be found
on most sailboats.

I also noticed that the switch twice did not shut off at all and this
is while brand new and clean in a test set up. Once down in the bilge
with some stuff floating around, who knows? Fortunately, West Marine
has a great return policy and took both switches back even though I
had to hack the wires short to remove them.

I've now done what I should have first thing, made some calculations
of my sump size and hose volume. I want generous pumping capacity
which means 1 1/8" hose to avoid head losses in the long runs. The
volume of hose divided by the area of my sump is greater than the ON /
OFF range of any switch I have been able to locate.

I don't want to use check valves because a little bit of fluff sucked
into one could set up the endless pumping cycle. Also, if the water
drained back from the check valve, the line would essentially be
airbound.

I need a little over two inches of ON / OFF range and there ought to
be a half inch margin over that. I'm stumped. Anybody got any ideas?

--

Roger Long

I was about to respond that I am hearing pretty uniform reports of
dissatisfaction about the See Water stitch. Some report them dying in the
first month. A few with smoke and enough heat to melt the case.

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com

"

Two floats. Float A is on the bottom and is the float that operates the pump
switch. It's also locked in the down position by a trigger means.
Float B is located appropriately higher up. When the water level raises
Float B it unlatches Float A. Pump runs, Float B falls, resets latch, Float
A finally falls and relocks itself.
Probably several way to implement mechanically.
Downside is added complication.
BF

"Roger Long" wrote in message
...
Those of you who read my report on my grandiose bilge system know that
I ignored the advice of the capacitance switch builder who said they
couldn't cost less than a grand and work. Well, he was right. This is
a great idea but it's not ready for prime time on most boats.

I set the whole thing up in my basement in a tub about the size of my
bilge sump with the hose let uphill to simulate the run that will go
in the boat.

Other solid state, electronic float switches have a high "On" trigger
point and a lower "Off" trigger. The See Water is instant on when
water touches the probe. Even a splashed drop seems to set it off.
There is no ON time delay at all. The instant the water drops below
the probe, an 8 - 10 second time delay starts. This is to draw the
water down low enough that backflow through the hoses won't set up an
endless cycle that drains the batteries. Unfortunately, the time delay
is totally inadequate for the length of hose run that would be found
on most sailboats.

I also noticed that the switch twice did not shut off at all and this
is while brand new and clean in a test set up. Once down in the bilge
with some stuff floating around, who knows? Fortunately, West Marine
has a great return policy and took both switches back even though I
had to hack the wires short to remove them.

I've now done what I should have first thing, made some calculations
of my sump size and hose volume. I want generous pumping capacity
which means 1 1/8" hose to avoid head losses in the long runs. The
volume of hose divided by the area of my sump is greater than the ON /
OFF range of any switch I have been able to locate.

I don't want to use check valves because a little bit of fluff sucked
into one could set up the endless pumping cycle. Also, if the water
drained back from the check valve, the line would essentially be
airbound.

I need a little over two inches of ON / OFF range and there ought to
be a half inch margin over that. I'm stumped. Anybody got any ideas?

--

Roger Long

Here is the electronic version of what you are talking about, a
latching relay.

http://home.maine.rr.com/rlma/Switch.jpg

The lower float switch goes on and nothing happens. When the top
switch goes on, current flows through the relay which closes a contact
that then bypasses the upper float switch. When the upper float
switch goes off, the relay remains on and the pump keeps running.
When the lower float switch goes back off, the circuit is interrupted,
the relay springs back, and the pump stops.

All this needs to work is a relay rugged enough to handle the current
draw of the pump without heating up or contributing too much voltage
drop. If anyone has specs handy for such a unit, I'd appreciate a
model number because I'll build this thing and report on it.

--

Roger Long

OR with electric logic. Both switches closed to start.
Lo switch closed to keep running. (Hi switch is shorted out by relay in
parallel with pump)
"BF" wrote in message
...
Two floats. Float A is on the bottom and is the float that operates the
pump
switch. It's also locked in the down position by a trigger means.
Float B is located appropriately higher up. When the water level raises
Float B it unlatches Float A. Pump runs, Float B falls, resets latch,
Float
A finally falls and relocks itself.
Probably several way to implement mechanically.
Downside is added complication.
BF

"Roger Long" wrote in message
...
Those of you who read my report on my grandiose bilge system know that
I ignored the advice of the capacitance switch builder who said they
couldn't cost less than a grand and work. Well, he was right. This is
a great idea but it's not ready for prime time on most boats.

I set the whole thing up in my basement in a tub about the size of my
bilge sump with the hose let uphill to simulate the run that will go
in the boat.

Other solid state, electronic float switches have a high "On" trigger
point and a lower "Off" trigger. The See Water is instant on when
water touches the probe. Even a splashed drop seems to set it off.
There is no ON time delay at all. The instant the water drops below
the probe, an 8 - 10 second time delay starts. This is to draw the
water down low enough that backflow through the hoses won't set up an
endless cycle that drains the batteries. Unfortunately, the time delay
is totally inadequate for the length of hose run that would be found
on most sailboats.

I also noticed that the switch twice did not shut off at all and this
is while brand new and clean in a test set up. Once down in the bilge
with some stuff floating around, who knows? Fortunately, West Marine
has a great return policy and took both switches back even though I
had to hack the wires short to remove them.

I've now done what I should have first thing, made some calculations
of my sump size and hose volume. I want generous pumping capacity
which means 1 1/8" hose to avoid head losses in the long runs. The
volume of hose divided by the area of my sump is greater than the ON /
OFF range of any switch I have been able to locate.

I don't want to use check valves because a little bit of fluff sucked
into one could set up the endless pumping cycle. Also, if the water
drained back from the check valve, the line would essentially be
airbound.

I need a little over two inches of ON / OFF range and there ought to
be a half inch margin over that. I'm stumped. Anybody got any ideas?

--

Roger Long

The other cool thing about relays is that they usually have multiple
contacts. If you want a cycle counter, pilot light, bell, or whistle,
it's just a matter of wiring it in. There are usually N.C. contacts
as well so, if there was something you didn't want to run at the same
time as the bilge pump, you could do that easily as well.

I'd wire the latching circuit across more than one set of contacts in
case of corrosion.

--

Roger Long

Change the circuit so that the relay coil is in parallel with the pump, and
the relay coil is in parallel with the upper switch. Any old 12V relay where
the contacts will carry the load of the pump will do.

"Roger Long" wrote in message
...
Here is the electronic version of what you are talking about, a
latching relay.

http://home.maine.rr.com/rlma/Switch.jpg

The lower float switch goes on and nothing happens. When the top
switch goes on, current flows through the relay which closes a contact
that then bypasses the upper float switch. When the upper float
switch goes off, the relay remains on and the pump keeps running.
When the lower float switch goes back off, the circuit is interrupted,
the relay springs back, and the pump stops.

All this needs to work is a relay rugged enough to handle the current
draw of the pump without heating up or contributing too much voltage
drop. If anyone has specs handy for such a unit, I'd appreciate a
model number because I'll build this thing and report on it.

--

Roger Long

Roger Long wrote:
Those of you who read my report on my grandiose bilge system know that
I ignored the advice of the capacitance switch builder who said they
couldn't cost less than a grand and work. Well, he was right. This is
a great idea but it's not ready for prime time on most boats.

snip

Well at least you have sense enough to recognize that if feels sooo good
when you stop hitting yourself in the head with a hammerg.

BTW, you'll never make capacitance work in that application.

I'm not going to tell you what will work since some schlock will try to
then build some cheapo version and sell it to an unsuspecting public.

Two choices, both will work.

1) Install a Whale manual pump with 1-1/2" hose. Every day, stroke that
puppy a few times.

Several benefits including exercise and it allows you to monitor the
condition of the bilge on a daily basis.

2) Install an electric pump with discharge where you can observe it.
Wire in a Son-A-Lert in parallel with the pump motor.

The more obnoxious the sound generated by the Son-A-Lert, the better.

BTW, a Son-A-Lert is just a 12 VDC, panel mounted alarm about 1-1/2" in
dia and relatively low cost available at any decent electronics outlet.

You turn the pump on, bilge water gets pumped out and you have to listen
to this awful noise.

Trust me, you will learn to watch that discharge like a hawk so you can
shut the damn pump off.

Do it every day and it will also monitor the condition of the bilge, if
you can stand the noise.

Worked for me for over 10 years before selling boat.

YMMV.

Lew

I must be having an obtuse moment because I'm having trouble see what
you mean. Any chance you could sketch it?

Is this change necessary to use an ordinary 12 V. relay or just an
improvement?

--

Roger Long



"barry lawson" wrote in message
...
Change the circuit so that the relay coil is in parallel with the
pump, and
the relay coil is in parallel with the upper switch. Any old 12V
relay where
the contacts will carry the load of the pump will do.

Oh of course. Like this, right?

http://home.maine.rr.com/rlma/Switch.jpg

(I loaded the new sketch into the same URL)

I remember now the big fog lights I had on a car years ago. There was
a relay under the hood so all the juice for the big lights wouldn't be
running through the tiny switch in the panel. The relay was pretty
well sealed and intended to survive under the hood of a car so should
do pretty well if kept above the bilge water. I'll look for a couple
of those tomorrow.

--

Roger Long

In article ,
"Roger Long" wrote:

I've now done what I should have first thing, made some calculations
of my sump size and hose volume. I want generous pumping capacity
which means 1 1/8" hose to avoid head losses in the long runs. The
volume of hose divided by the area of my sump is greater than the ON /
OFF range of any switch I have been able to locate.

I don't want to use check valves because a little bit of fluff sucked
into one could set up the endless pumping cycle. Also, if the water
drained back from the check valve, the line would essentially be
airbound.

Our check valve worked just fine for about a decade. The primary reason
I put it in was because our stern wave sometimes comes halfway up our
transom and I don't like the idea that the bilge pump hose could lead
that water into the boat.

One trick that could change the mix: Add a vacuum break elbow close to
the pump, but above the moving waterline

--
Jere Lull
Xan-a-Deux ('73 Tanzer 28 #4 out of Tolchester, MD)
Xan's Pages: http://members.dca.net/jerelull/X-Main.html
Our BVI FAQs (290+ pics) http://homepage.mac.com/jerelull/BVI/

On Sun, 15 May 2005 23:57:08 GMT, "Roger Long"
wrote:

Oh of course. Like this, right?

http://home.maine.rr.com/rlma/Switch.jpg

(I loaded the new sketch into the same URL)

I remember now the big fog lights I had on a car years ago. There was
a relay under the hood so all the juice for the big lights wouldn't be
running through the tiny switch in the panel. The relay was pretty
well sealed and intended to survive under the hood of a car so should
do pretty well if kept above the bilge water. I'll look for a couple
of those tomorrow.


Now, you're talking.
1) Make that a 12 volt relay with two normally open
20A DC rated switches
2) Dedicate one switch to the pump supply.
3) Add a snubber of 10 ohms in series with 0.01 microfarad (200 volt +
working)
across each of the two inductive pieces, which are
3.1) the relay coil
3.2) The motor inputs

4) Remember that sparking contacts in the vicinity of a gas
tank/engine make loud noises, so a metal clad relay would be better,
in a decent blade socket.

Brian Whatcott Altus, OK

Brian Whatcott Altus OK

That's it. Headlight relay might do, just make sure it is meant to be on all
the time; not short term like a horn relay might be.
"Roger Long" wrote in message
...
Oh of course. Like this, right?

http://home.maine.rr.com/rlma/Switch.jpg

(I loaded the new sketch into the same URL)

I remember now the big fog lights I had on a car years ago. There was
a relay under the hood so all the juice for the big lights wouldn't be
running through the tiny switch in the panel. The relay was pretty
well sealed and intended to survive under the hood of a car so should
do pretty well if kept above the bilge water. I'll look for a couple
of those tomorrow.

--

Roger Long

It's a diesel boat.

Would you please explain the snubber business? I'm sure a lot of us
besides myself would like to know what it's for.

--

Roger Long



"Brian Whatcott" wrote in message
...
On Sun, 15 May 2005 23:57:08 GMT, "Roger Long"
wrote:

Oh of course. Like this, right?

http://home.maine.rr.com/rlma/Switch.jpg

(I loaded the new sketch into the same URL)

I remember now the big fog lights I had on a car years ago. There
was
a relay under the hood so all the juice for the big lights wouldn't
be
running through the tiny switch in the panel. The relay was pretty
well sealed and intended to survive under the hood of a car so
should
do pretty well if kept above the bilge water. I'll look for a
couple
of those tomorrow.


Now, you're talking.
1) Make that a 12 volt relay with two normally open
20A DC rated switches
2) Dedicate one switch to the pump supply.
3) Add a snubber of 10 ohms in series with 0.01 microfarad (200 volt
+
working)
across each of the two inductive pieces, which are
3.1) the relay coil
3.2) The motor inputs

4) Remember that sparking contacts in the vicinity of a gas
tank/engine make loud noises, so a metal clad relay would be better,
in a decent blade socket.

Brian Whatcott Altus, OK

Brian Whatcott Altus OK

On Mon, 16 May 2005 01:18:55 GMT, "Roger Long"
wrote:

It's a diesel boat.

Would you please explain the snubber business? I'm sure a lot of us
besides myself would like to know what it's for.


An inductive element like a relay coil or a motor stator or rotor
has a predictable reaction to suddenly cutting off the current through
it: a back voltage which can rise to a fast peak of hundreds of volts,
making a spark that jumps the opening contacts for a little while.

This wears the contacts out. And ignites gasoline vapor too.

If something is arranged to let the current through a coil fall more
slowly, the voltage rise is much lower. If some resistance is in
circuit, the energy stored in the coil is used by the resistance -
which heats up a little.
This combination of a capacitor and series resistor is called a
snubber, because it snubs (or damps out) the spark.
The cap and resistor is placed across the coil.

Make sense?

Brian Whatcott Altus, OK

Like this, right?

http://home.maine.rr.com/rlma/Switch.jpg

I can appreciate the effect. I made a box in high school with a coil
in it and a switch made from a nail dangling in a ring. It had
textured aluminum foil sides wired to the coil and said "Mystery Box"
on top. It was a hoot when I left it in the faculty room.

Do you think I can get away with a single contact relay? The sealed
fog light relays that are readily available seem like they should be
sized and just right for this application.

--

Roger Long

"Roger Long" wrote in
:

Like this, right?


Oh, goody-goody! Let's all keep making the damned bilge pump more and more
complex, with lots more failure points so it can flood the damned boat and
put it on the bottom.....

Parallel two Rule float switches in series with EACH of two bilge pumps
hooked straight up to the batteries through a 3A fuse....

The boat will never sink.....until the flooding exceeds the combined
capacity of the pumps, of course.

SIMPLE IS ALWAYS BETTER!

On Mon, 16 May 2005 09:15:37 -0400, Larry W4CSC
wrote:

Oh, goody-goody! Let's all keep making the damned bilge pump more and more
complex, with lots more failure points so it can flood the damned boat and
put it on the bottom.....

Parallel two Rule float switches in series with EACH of two bilge pumps
hooked straight up to the batteries through a 3A fuse....

The boat will never sink.....until the flooding exceeds the combined
capacity of the pumps, of course.

SIMPLE IS ALWAYS BETTER!

Yeah, what he said.

__________________________________________________ __________
Glen "Wiley" Wilson usenet1 SPAMNIX at world wide wiley dot com
To reply, lose the capitals and do the obvious.

Take a look at cpRepeater, my NMEA data integrator, repeater, and
logger at http://www.worldwidewiley.com/

Larry W4CSC wrote:

"Roger Long" wrote in
:


Like this, right?



Oh, goody-goody! Let's all keep making the damned bilge pump more and more
complex, with lots more failure points so it can flood the damned boat and
put it on the bottom.....

Parallel two Rule float switches in series with EACH of two bilge pumps
hooked straight up to the batteries through a 3A fuse....

The boat will never sink.....until the flooding exceeds the combined
capacity of the pumps, of course.

Or, of course, the capacity of the batteries.



--
Stephen

-------

For any proposition there is always some sufficiently narrow
interpretation of its terms, such that it turns out true, and
some sufficiently wide interpretation such that it turns out
false...concept stretching will refute *any* statement, and will
leave no true statement whatsoever.
-- Imre Lakatos

"Stephen Trapani wrote:

Or, of course, the capacity of the batteries.

And, in this case, it would have had to be pretty impressive capacity.
After the fiasco with the oil sensing switches, I'm all for the
simplicity promoted above. What's driving this now is the fact that
the pumping capacity I want (enought to have a fighting chance of
surviving a burst stuffing box hose), combined with the hose lengths
forced by the design of the boat, means that any float switch on the
market will go into an endless cycle of pumping out the hose.

--

Roger Long

Roger Long wrote:

"Stephen Trapani wrote:


Or, of course, the capacity of the batteries.


And, in this case, it would have had to be pretty impressive capacity.
After the fiasco with the oil sensing switches, I'm all for the
simplicity promoted above. What's driving this now is the fact that
the pumping capacity I want (enought to have a fighting chance of
surviving a burst stuffing box hose), combined with the hose lengths
forced by the design of the boat, means that any float switch on the
market will go into an endless cycle of pumping out the hose.

****ing big centrifugal pump (or even two) with big hose with its float
switch mounted above that for a little, positive displacement diaphram
pump with a small hose?

The little pump doesn't affect the reliability of the big one but should
be enough to cope with the runback from the big hose.

Alternatively, back to the relay idea:
Take big pump and upper float switch (NO), wire in series, pump -ve to
batt -ve, other side of switch to +ve supply. Wire the relay (NO)
contacts accross the upper float switch. Wire a lower float switch (NO)
in series with the relay coil and feed it from the pump motor +ve.
Return the other side of the relay coil to the pump -ve (which is also
the battery -ve) Wire RC snubbers accross both the relay coil and the
motor as near as practical to them and a reasonably tolerable buzzer
accross the motor. Feed from an appropriate fuse directly off the
battery with a high dB output pizeo beeper accross the fuse. Put the
sounders and the relay (in a socket) somewhere where you can get at them
if you have to. e.g. back at the panel. You need four wires down to
the bilge, (Upper switch +ve, common junction of upper switch -ve &
lower switch +ve & motor +ve, lower switch -ve [to relay coil], motor -ve)

Now lets consider the possible failure modes:

1. Upper switch fails open: No alarm, bilge can flood silently till boat
sinks.

2. Upper switch fails closed: Continuous buzzer, bilge is emptied until
eventual flat battery or pump burnout

3. Motor OC: Continuous buzzer if enough water in bilge until the boat
sinks

4. Motor SC (or jammed so fuse blows): Continuous extremely loud
unignorable high pitched tone untill fault cleared and fuse replaced,
beeper smashed or disconnected :-) or boat sinks

All the above are the same as for a simple pump setup with one switch
and no relay. The only difference is you have two audiable alarms.

5. Relay fails open or lower switch fails open: Circuit reduced to
simple switch and pump, you hear a double (or more) buzz due to runback
restarting the pump, boat does not sink.

6. Relay fails closed or lower switch fails closed: Continuous buzzer,
bilge is emptied until eventual flat battery or pump burnout or untill
you pull the relay out of its socket which puts it back to the simple
single switch case.
**** This is the only increased risk ****

The snubbers have a resistor + a capacitor in the same package.
Resistors almost always fail by going open circuit which would make the
snubber ineffective but not cause an immediate circuit failure or the
capacitor might short, in which case the resistor would limit the
current until it went open and the circuit would keep working. If you
are fairly (justifiably?) paranoid, you might use two snubbers in
parallel in place of a single one in each circuit position.

Finally for backup security fit the second pump which only needs a
simple switch a little higher in the bilge than the first pump's upper
switch with pizeo sounder accross its fuse and another accross the pump
(+ another RC snubber) off your other battery. This catches any fault
with the first pump that haven't sounded its alarm.

(NO stands for Normally Open contacts)

N.B. *DONT* PUT THE LOWER SWITCH FOR THE FIRST PUMP IN SERIES WITH ITS
MOTOR (as per your JPEG) OR YOU DOUBLE THE CHANCE OF A FAILED SWITCH
STOPPING THE PUMP WORKING WITH NO ALARM.

Hope that helps, Roger.
Have I missed anything Larry?
--
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:
'Stingo' Albacore #1554 - 15' Early 60's, Uffa Fox designed,
All varnished hot moulded wooden racing dinghy.

On Mon, 16 May 2005 10:30:55 GMT, "Roger Long"
wrote:

Like this, right?

http://home.maine.rr.com/rlma/Switch.jpg

I can appreciate the effect. I made a box in high school with a coil
in it and a switch made from a nail dangling in a ring. It had
textured aluminum foil sides wired to the coil and said "Mystery Box"
on top. It was a hoot when I left it in the faculty room.

Do you think I can get away with a single contact relay? The sealed
fog light relays that are readily available seem like they should be
sized and just right for this application.


I am sure you can get away with the one pole switch relay - but the
float switch then takes the motor current make and break and I suspect
the usual float switch won't feature 20 Amp contacts - but an auto
relay will. So there's a life trade-off.
If you can source a two pole relay, let the float switches handle the
modest relay current, and the second relay switch then handles any
reasonable - even unreasonable - bilge pump load.

Brian Whatcott Altus OK

I found LD1A-12F headlight/horn relays for six bucks at the auto
store and available here for less:

http://www.jameco.com/Jameco/catalogs/c252/P138.pdf

where I've ordered sockets with coil suppression diodes. The relays
are completely sealed and appear to be as watertight and ignition safe
as any marine unit. 30 Amp, 220 watts. It'll be a simple matter to
carry a spare and they can serve as the shut off switches if the pump
jambs.

I got the parts for the snubbers. Does the presence of the diode in
the socket change anything?

Many thanks for your help on this. It's what this group should be for
instead of worrying about who's pretending to be Peggie.

--

Roger Long

I'm not sure that there needs to be any snubbing in this arrangement.
For one thing, a 30 amp contact should easily handle the surge of 12 volt
bilge pump circuit being broken.
But mainly:
the relay connects across the hi level switch (after that switch has closed)
then when the hi level switch opens, the relay stays closed
and after the lo level switch opens (stopping the pump)
the relay opens.
So the relay never sees any starting or stopping load.

wot sort of switches are you using? I've had a terrible run with Rule. The
most reliable one I have sounds like it has a ball inside that runs along
and makes contact when the body tilts.

"Roger Long" wrote in message
...
I found LD1A-12F headlight/horn relays for six bucks at the auto
store and available here for less:

http://www.jameco.com/Jameco/catalogs/c252/P138.pdf

where I've ordered sockets with coil suppression diodes. The relays
are completely sealed and appear to be as watertight and ignition safe
as any marine unit. 30 Amp, 220 watts. It'll be a simple matter to
carry a spare and they can serve as the shut off switches if the pump
jambs.

I got the parts for the snubbers. Does the presence of the diode in
the socket change anything?

Many thanks for your help on this. It's what this group should be for
instead of worrying about who's pretending to be Peggie.

--

Roger Long

Sorry to hear about your experience with Rule since I have two of
them. I'm whipping myself soundly for buying mercury switches after
preaching against them but they didn't have any clean ones in the
store. I'm glad to hear that the rolling ball ones are reliable.
Johnson makes one which I'll try to get a pair of them for the bottom
set.

I understand that the Rule's go because the repeated flexing breaks
the wires going to the switch. Is that consistent with your
experience?

I really appreciate the advice on the snubbing because incorporating
it was going to required a whole enclosure for the switch set up.

--

Roger Long



"barry lawson" wrote in message
...
I'm not sure that there needs to be any snubbing in this
arrangement.
For one thing, a 30 amp contact should easily handle the surge of 12
volt
bilge pump circuit being broken.
But mainly:
the relay connects across the hi level switch (after that switch has
closed)
then when the hi level switch opens, the relay stays closed
and after the lo level switch opens (stopping the pump)
the relay opens.
So the relay never sees any starting or stopping load.

wot sort of switches are you using? I've had a terrible run with
Rule. The
most reliable one I have sounds like it has a ball inside that runs
along
and makes contact when the body tilts.

Roger Long

Roger Long wrote:

I really appreciate the advice on the snubbing because incorporating
it was going to required a whole enclosure for the switch set up.

Minimum Snubbing, put a snubber across the pump motor. If you solder
stranded wires onto the resistor and the capacitor and twist and solder
the two components in series then put in a n old 35mm film canister and
pour in epoxy resin (glass microbubbles would be fine as a filler), you
will have a sealed unit you can connect to the motor terminals.

Why not post a link to the new circuit diagram for some peer review of
the final design?


--
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:
'Stingo' Albacore #1554 - 15' Early 60's, Uffa Fox designed,
All varnished hot moulded wooden racing dinghy.

Why would the pump motor need snubbing in this design more than in the
usual set up? Or, is snubbing one of those things that is always a
good idea but seldom done?

Good idea on the potting.

I've been constantly updating the jpg behind the original link which
is:

http://home.maine.rr.com/rlma/Switch.jpg

The socket I'm getting for the relay has a "coil suppression diode".
I assume that is intended to do the same sort of thing by preventing
current from flowing in reverse when the field collapses through the
coil.

--

Roger Long



"Ian Malcolm" wrote in
message ...
Roger Long wrote:

I really appreciate the advice on the snubbing because
incorporating it was going to required a whole enclosure for the
switch set up.

Minimum Snubbing, put a snubber across the pump motor. If you
solder stranded wires onto the resistor and the capacitor and twist
and solder the two components in series then put in a n old 35mm
film canister and pour in epoxy resin (glass microbubbles would be
fine as a filler), you will have a sealed unit you can connect to
the motor terminals.

Why not post a link to the new circuit diagram for some peer review
of the final design?


--
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:
'Stingo' Albacore #1554 - 15' Early 60's, Uffa Fox designed,
All varnished hot moulded wooden racing dinghy.

Roger Long wrote:
Why would the pump motor need snubbing in this design more than in the
usual set up? Or, is snubbing one of those things that is always a
good idea but seldom done?
Snubbing provides a path for the current flowing in a coil to decay into
rather than sparking accross the opening switch contacts. The bigger
the coil the more it needs snubbing. Worst case, the arc can actuallly
weld the contacts so they dont switch no more. Lack of snubbing on
motor loads is probably a major factor in the notorious poor reliability
of float switches.



Good idea on the potting.

I've been constantly updating the jpg behind the original link which
is:

http://home.maine.rr.com/rlma/Switch.jpg

Hmm, if EITHER switch fails open, you loose the pump. If you move the
pump +ve to the JUNCTION of the two switches (dont change anything
else), then only the top switch is critical. Also you could then
manually override the switches to run the pump by pulling the relay and
stuffing a (pre prepared?) jumper wire down the appropriate contacts of
the socket. Otherwise it WILL work the way its ment to, the discussion
is now just "Can we 'gold plate' it at no/little extra cost?".

The socket I'm getting for the relay has a "coil suppression diode".
I assume that is intended to do the same sort of thing by preventing
current from flowing in reverse when the field collapses through the
coil.
Yes and No. it does the same thing by letting the existing current in
the relay coil flow round and round chasing its own tail until it
dwindles to nothing. If you ever want an electric 'palm tingler' try a
9v battery, and a fairly chunky relay connected so as to open its own
coil currrent circuit (no snubbers/diodes). Typically it will develop a
couple of hundred volts accross the contacts. Oddly enough, this is the
first thing about relays an average to bright 10 year old will discover
.. . . :-)

I'm off sailing for a couple of days, back Friday. Probably get to spend
this afternoon upsidown is someon else's bilge & lockers looking at
'lectrickery. . .
--
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:
'Stingo' Albacore #1554 - 15' Early 60's, Uffa Fox designed,
All varnished hot moulded wooden racing dinghy.

Gawd that's clever!

However, just as I'm rediscovering how much fun electricity can be,
I've come up with a non electrical solution.

The float switches should be protected from sloshing and debris so I
have to build an enclosure anyway. If I just put a PVC pipe siphon in
it like this:

http://home.maine.rr.com/rlma/Siphon.jpg

it should work just like the electrical circuit.

Anybody need a couple of headlight relays with sockets and snubber
components?

--

Roger Long



"Ian Malcolm" wrote in
message ...
Hmm, if EITHER switch fails open, you loose the pump. If you move
the pump +ve to the JUNCTION of the two switches (dont change
anything else), then only the top switch is critical.