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#11
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Bilge Pump Switch
We recently installed a "automatic" pump in the forward bilge on one of
the charter boats. The way I understand it, the pump spins its impeller and if it detects water, it keeps pumping. No external switch needed. Have a look at the link below. http://www.westmarine.com/webapp/wcs...productId=2576 Capt. Frank Keith wrote: Groco makes an air activated switch like this for boats. I have one in mine and love it. The only thing sticking down into the bilge is a little bell shaped upside down "cup" with the hose leading up to the switch, a couple of feet above. When the water rises, the pressure inside the switch triggers the bilge pump. "MIDEMETZ" wrote in message ... I used a water switch from a washing machine. I don't remember the size of the PVC cap but it was used by a lot of the local shrimpers in their old wooden boats ( read leak a lot ). The switch is usually in the control top part. They recommended using a smaller longer hose and mounted the switch high on the bulkhead. Mine worked for a little over 5 years with out problems. ( Sold the boat ). It would take a little experimenting but easy engulf to find the cap size. They heater a brass hose barb and just screwed it in to the hole, I drilled & taped it. It isn't boat pretty but very useful. For the delay the Radio Shack idea seems the best. Mike. ***************** However I am sick of replacing bilge pump switches. ( I have a shed full of floats!) I thought to seal a mercury switch and put it on the float when the float goes up the pump comes on (through a good relay) However the switch comes on the pump runs for a very short time and just clicks on and off driving the relay crazy. I need to have a delay that will keep the relay pulled in say 5 to 10 seconds before dropping out and resetting. Anyone have an idea or circuit that will do this for me. Thanks Oliver Fleming |
#12
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Bilge Pump Switch
"Meindert Sprang" wrote in message ... "Vito" wrote in message ... del cecchi wrote: "Larry Demers" wrote ... A series cap with the diode seems like a better idea to try. This is a DC system in the average boat. There is only one polarity of inductive kick. Diodes work fine. Capacitors in series with the diode wouldn't work at all. That's odd considering that literally millions of DC automobile ignition systems used a capacitor in parallel with the "points" to protect them from the coil's inductive kick. BTW, the "kick" is damped AC. That has a different reason. Damping a coil with a diode does the job, since the induction voltage is ALWAYS the opposite as the originating voltage. But, using a diode keeps the current flowing while the magnetic field collapses. This causes a slow collapse of the field. In a coil in the car (is it called bobbin?) has to produce a high voltage and therefore the field has to collapse as fast as possible. Therefore a capacitor is used with certain value to get the best trade-off between generated high voltage and RF interference surpression. Meindert The capacitor across the points has its voltage reset to zero when the points close. The capacitor acts to supress arcing by slowing the rise time of the current decrease when the points open. The resulting oscillation in the series tuned circuit is damped by the secondary driving the spark through the plug. In the case of the relay coil, there is no secondary. If there were no diode, the tuned circuit would oscillate for a long time. With the diode, the inductive kick will be stored on the capacitor and, being unable to discharge through the reverse biased diode, will stay there for a long time. During that time the diode will never turn on, due to the voltage on the capacitor. del cecchi |
#13
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Bilge Pump Switch
Sigvaldi Eggertsson wrote:
The climate of Iceland is not much different from the UK one, maritime temperate with mild winters and cool summers. You were probably thinking about Greenland? I figured it must not be terribly bad in Iceland. Otherwise they would not be able to grow all those gorgeous women. :-) -- 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 I'veheard the rule of thumb esxpressed, "Geenland is white, but Iceland is green." |
#14
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Bilge Pump Switch
"Vito" wrote in message ... Meindert Sprang wrote: The small oscillation you get has nothing to do with mass of electrons and their inertia. It is caused by the fact that every coil has a bit of parasitic capacitance, forming a resonant loop with the inductance of the coil, ... Yes but Meindert old bean, if electrons didn't have inertia resonant circuits wouldn't resonate. Is this a feeble attempt at humor, or are you an idiot? Sometimes hard to tell on the net. del cecchi |
#15
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Bilge Pump Switch
Del Cecchi wrote:
"Vito" wrote Yes but Meindert old bean, if electrons didn't have inertia resonant circuits wouldn't resonate. Is this a feeble attempt at humor, or are you an idiot? Neither one. Do you doubt that electrons have mass and therefore inertia? If they did not, then current would stop at once when the coil unsaturated. But it does not. The little buggers keep going til they've charged the capacitor (parasitic in this case but still real). Then (Bugle sounds retreat) they head the other way re energizing the coil ..... etc. .... creating a damped AC wave. Sometimes hard to tell on the net. Yes indeed. |
#16
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Bilge Pump Switch
"Vito" wrote in message
... Del Cecchi wrote: "Vito" wrote Yes but Meindert old bean, if electrons didn't have inertia resonant circuits wouldn't resonate. Is this a feeble attempt at humor, or are you an idiot? Neither one. Do you doubt that electrons have mass and therefore inertia? If they did not, then current would stop at once when the coil unsaturated. But it does not. Sorry to say Vito, but that is completely nonsense. The reason current keeps folwing for a while is magnetism. Current flowing through a wire creates a magnetic field around the wire. Also, a changing magnetic field induces current in a wire. What happens when you open the contact is this: the current stops flowing, the existing static field collapses and is therefore changing. And the field change induces a current in the wire in the opposite direction. In a straight wire this effect is hardly noticable but coiled up, the field around the wire concentrates and the effect gets bigger. And if you still believe in electron inertia, I advise you to go and read a book about basic electric laws. Meindert |
#17
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Bilge Pump Switch
Meindert Sprang wrote:
And if you still believe in electron inertia, I advise you to go and read a book about basic electric laws. But Meindert, I weld from time to time and as you probably know welding requires large current flows. This means huge numbers of electrons are racing along the wire to the welding rod. I have noticed that when I pull the rod away from the work it always has a big blob on the end. Are you saying this isn't because all those electrons kept rushing into the hot metal and caused it to bulge out when they had no place to go? Rick |
#18
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Bilge Pump Switch
"Vito" wrote in message ... Del Cecchi wrote: "Vito" wrote Yes but Meindert old bean, if electrons didn't have inertia resonant circuits wouldn't resonate. Is this a feeble attempt at humor, or are you an idiot? Neither one. Do you doubt that electrons have mass and therefore inertia? If they did not, then current would stop at once when the coil unsaturated. But it does not. The little buggers keep going til they've charged the capacitor (parasitic in this case but still real). Then (Bugle sounds retreat) they head the other way re energizing the coil .... etc. .... creating a damped AC wave. Sometimes hard to tell on the net. Yes indeed. Next you will be telling me that you think the electrons are shooting through the wire so fast that they just keep going and end up in a pile on the other end, until they shoot back the other way. Snort, giggle, choke. Yes the electrons have mass. It has nothing to do with how they behave in electric circuits. |
#19
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Bilge Pump Switch
"Rick" wrote in message
news Meindert Sprang wrote: And if you still believe in electron inertia, I advise you to go and read a book about basic electric laws. But Meindert, I weld from time to time and as you probably know welding requires large current flows. This means huge numbers of electrons are racing along the wire to the welding rod. I have noticed that when I pull the rod away from the work it always has a big blob on the end. Are you saying this isn't because all those electrons kept rushing into the hot metal and caused it to bulge out when they had no place to go? :-)) By the way, take a good look at your car's headlights: if you take a right turn, the right headlight gets a little dim because all electrons are forced to the left side of the wiring in the car. You know, inertia, centrifugal forces and all.... Meindert |
#20
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Bilge Pump Switch
On Thu, 30 Oct 2003 19:45:41 +0100, "Meindert Sprang"
tempted fate with: By the way, take a good look at your car's headlights: if you take a right turn, the right headlight gets a little dim because all electrons are forced to the left side of the wiring in the car. You know, inertia, centrifugal forces and all.... Meindert I've worried about my VHF antenna. It's way up at the top of my mast. Are the electrons slowing down on the way up? And when they come falling back down the coax like little bombs and plow into my radio, can they damage it? Is there a radiation hazard? __________________________________________________ __________ Glen "Wiley" Wilson usenet1 SPAMNIX at worldwidewiley 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/ |
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