is there any diagrams out there that show the construction of a reliable automatic bilge pump switch?
You would think that BC or someone could probably sell these things ready made, or possibly pumps with them built in. The result would probably be neater and more reliable, since they would be built sort of production style.
Yes. It's two-fold really. Manual pumps do take a radio channel, which are normally in short supply and require additional thought on the captain's part, which can better be used for hammering away on the enemy vessel to port or starboard. Then there is the "always on" pump, but those suck down the battery full time, as well as many times won't consistently prime. I've seen many always on pumps (different/nearly every mfg of pumps, different ships, different clubs) where the ship will nearly sink before the pump primes. Automatic pump circuits allow you to put the sensor at the good position for the pump to consistently prime. Now with that said, all APC's aren't created equal, and can equal a quick sink. The diagram on the Queen's Own site is for a APC Mk1 circuit which has a high rate of failure on the water due to the transistor quality, the contact quality, and the TIP120's inability to handle high amperage loads (on the medium and larger sized pumps) without burning out. The diagram/article on the APC MKIII is in the NTXBG Knowledge Base: https://ntxbg.org/KnowledgeBase/?category_id=45&menuaction=phpbrain.uikb.view_article&art_id=16 Properly constructed the MkIII is foolproof. I've had no failures with 4 circuits and a few years. The be fair, there was one failure with a relay that burned out, but that was a 15A relay paired to a 30A pump motor. The MKIII is the result of a lot of experimentation and tweakage for a circuit that is easy to build. My next one is the MkIV which is microprocessor controlled with a lot of functionality for reliably getting water out, and I'm code complete, but the design is probably no longer buildable by the average Joe. Guess if I was smart, I'd call these the Burns Circuits or something... Cheers Jeff
BC did sell an APC MKII variant at one point. It had some of the same troubles as my MkII with not always starting up. I don't think they made it to a MKIII variant prior to ceasing sales though.
I have a question about the high failure rate of the Queens Own type auto pump circuit. I have not seen a high failure rate in the past eight years with this circuit. Were failures seen on 6 or 12 volt systems? Were these failures seen on Queens Own pumps that are rated at GPH (gallons per hour and motors are choosen to meet that GPH)or on pumps that have an output diameter restriction but not a total output limit. The reason I ask is that late last year I started battling with PortPolarBear and I use the same circuit on the restricted output pumps and I am interested in what type of pump you saw fail and if I need to make a change. Thanks for your time, RiverRaider
The failures I've seen locally in NTXBG were either the TIP120 burning up, failing to trigger, or the pump speed would vary according to the conductivity of the water. The latter I consider a failure, but it's more of a shortcoming of using a TIP120 wired straight into the pump motor. If the TIP or other NPN transistor is tied to a relay, then the pump always gets full voltage. I don't know about other places, but the water around here in the winter isn't as conductive as it is in the summer (not as much "floating around" in it I suppose). The Mk1 and MkII circuits both had troubles with wintertime water around here. The combination of a better transistor and gold contacts used in the MKIII design made a huge difference in both performance and reliability. The pumps used were between 45GPH and 90GPH. Cheers Jeff
Yep, Gold contacts make a world of difference, and that's what makes even a relatively insensitive TIP120 workable. Combined with the 2N5307 and a appropriately rated relay, it's superb. Cheers Jeff
MAYDAY MAYDAY she’s going down all hands mand the pumps okay I haven’t even been in a battle yet just shakedown runs and low and behold my pump failed [V] first run the other day I put cups full of water in my ship to test the auto switch worked the balls but than it stuck on I chocked it up to my leads where to close together I would move it before NATS all is well than today I got a new battery and I wired it up so I plugged it in to test the connections (I’m not that great with solder iron) and the pump wouldn’t turn on while I had a piece of metal wedged between contacts. I walked away 10 min later it came on and than wouldn’t turn off again even when I removed the peice of metal I think the ghost of Admiral Isoroku Yamamoto has taken up residence in my bilge so I need either a good pump tech or a good preist []
Yo Monk. Not a lot of actual details there. Sounds like you miswired somewhere. What transistor did you use? Is the resistor inline from the Base to the sensor? What sensor material was used. Where are the sensors? Have you spread skotchkote on the completed package to keep it from getting wet? What relay is being used? Is it sealed? Jeff
Okay I got my schematics on Qo and followed them to a T even found a mistake on the radio shack part number after befuddling the clerk and my self before we figured it out and the pats are Radio shack #276-2068 Tip 120 Darlington transformer Radio shack #271-1325 2.2-ohm Resistor ¼ watt.5% and the motor has 3 capacitors Radio shack # 272-1069 + to can – to can + to -
Separate issue, those polyester Caps aren't the greatest for getting keeping the noise suppressed. Ceramic is better, but that's a separate matter. I will say the Radio Shack TIP120 is a very bad transistor for this as it's not very sensitive. It has a bad tendency to not start up in a timely manner. What's up on QO is the initial MKI design. See the updated schematic and parts list for the MKIII here: The diagram/article on the APC MKIII is in the NTXBG Knowledge Base: https://ntxbg.org/KnowledgeBase/?category_id=45&menuaction=phpbrain.uikb.view_article&art_id=16 Since Radio Shack got out of most of the electronics biz, there is either Altex, Fry's, or your local surplus electronics vendor for picking up parts if you don't want to get them from an internet vendor. For the picture above, the sensors are indeed too close together. Need to move them apart by an inch or so so that the moisture stay stuck between them keeping it locked on. I may update my article with some extra info.
Okay that’s all great but I looked at your schematics and I have to say I'm lost the Qo was just my speed slow to moron [] do you have it simplified for us none electronic guys []
The QO I could get in my car drive to radio shack read the # of what I need and drive home and knowing I had the right stuff put it together see monk proof []
