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Post by Deleted on Feb 23, 2020 18:58:34 GMT
240 won't suit foxy's boat as it would require a large inverter. naughtyfox this thing you mention about the flow varying. Jabsco did do an infinitely variable water pump which did not need an accumulator. I tried one once but it was faulty. I wonder if that's what you have. Not sure if they still do them or not.
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Post by Deleted on Feb 23, 2020 19:12:52 GMT
I didn't read it properly.
Going back to your suggestion of excess pressure it's an interesting point. Would excess pressure on a diaphragm pump of this kind put extra load on the electric supply line increasing the amp draw?
I would think not but I suppose it's possible.
Might be a good one for the technical experts.
Like getting the engineering students to wire up a 3 pin plug and see how they do it.
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Post by metanoia on Feb 23, 2020 19:38:14 GMT
There seem to be only us and 2-3 other live boats here... Ooh...………… Oh no …. ….pity those poor boats/boaters
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Post by JohnV on Feb 24, 2020 13:59:06 GMT
if you can't turn the armature (thing with the copper wire coil on it) in the casting it's still attached to then it is seized.
either the bearing or the drive for the pistons inside that housing (looking at the colour of the left hand brush holder in the picture it might have been tightening up for a while and getting warm)
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Post by IainS on Feb 24, 2020 14:22:27 GMT
(snip) I don't understand it at all. You turn the water pump switch on and it starts buzzing even though no taps are open. The flow rate is the same as we had before. When you turn the tap off the pump keeps running but slower and slower and at this stage the fuse pops out. We can pre-empt this by turning the switch off, at which the pump stops dead. But.... is there excess water pressure somewhere... because when we turn the taps on water comes out at a decent flow for a few seconds. I think we will ask about a new Jabsco pump and if we can find the right model Derek could put it on for us... Soon to run through our old BSS report and see how we need to present the boat tomorrow morning. Not expecting any problems at all with that. Sounds very like the pressure switch is stuck on. As the pressure increases, it becomes more difficult to turn the pump, as it's working against a much higher pressure. The motor slows, and current increases. End result can be either blown fuse or a really hot and burnt out motor. There isn't a lot that can go wrong with pump pressure switches. If there's no water on the "dry" side of the switch, then the switch diaphragm is OK, and fault is either the microswitch or a blockage in the pressure switch. On the "wet" side of the switch diaphragm there is usually a plastic disc with a very small hole in it. This hole can be opened out to 4mm or so without ill effect. It's a good idea to replace the microswitch anyway, as even if it tests out OK, as a fault there can be intermittent and disturbing the switch can provide a temporary cure. The microswitch isn't really man enough for the job, and it's a good idea to add an automotive type relay so that the switch only switches the coil current while the relay switches the motor current. If you've got a replacement pump, sort the pressure switch on the old one, and keep it as a spare. Sod's Law says that if you carry a spare, you won't need it, but if you don't, you will.
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Post by IainS on Feb 24, 2020 14:34:18 GMT
(snip) Going back to your suggestion of excess pressure it's an interesting point. Would excess pressure on a diaphragm pump of this kind put extra load on the electric supply line increasing the amp draw? I would think not but I suppose it's possible. (snip) It does. When an electric motor is spinning, it generates a voltage in opposition to the voltage driving it. Hence, startup current is a lot higher than running current. If the motor is loaded, it slows slightly, the voltage it's generating decreases, the voltage seen by the armature increases towards the supply voltage, and current drawn increases. A sort of negative feedback loop.
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Post by IainS on Feb 24, 2020 14:51:59 GMT
Finally got a moment to disembowel our old water pump. I can't turn any axle/spindle with mole grip pliers. What is it that is supposed to turn? I recognise the carbon brushes, and they bounce in and out nicely on their springs. Could these have become worn out and simply new brushes would have sufficed? Anyway, new Jabsco pump being ordered, and might as well have a new accumulator at the same time. (snip) (snip) That bit should spin freely on the front plate. (If the pump was working, it MUST be turning) There will be either a ball bearing or a plain bush in the motor's front plate. A drop of thin oil or a spray with easing oil should start it moving, and once it frees up, it should be OK. When re-assembling, a smear of grease or drop of oil on the back bearing is a good idea as well. The commutator looks serviceable, but might benefit from a gentle clean up. A strip of emery cloth or wet and dry is good for this, but be careful to clean it afterwards so that no abrasive is left behind.
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Post by Deleted on Feb 24, 2020 15:41:40 GMT
Did you pass the BSS ? Guess yes as you've bought coal Rog
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Post by Deleted on Feb 24, 2020 17:48:08 GMT
You said your wife wouldn't let you buy coal until the BSS examiner had been. You said you'd bought coal. You also said you'd pass no problem, so I assumed (wrongly) that as you'd got coal it was all done with successfully. That's what coal's got to do with it naughtyfox ... don't get 'eggy' just cos you failed. Rog
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Post by Mr Stabby on Feb 24, 2020 18:04:24 GMT
Did you pass the BSS ? Guess yes as you've bought coal What' s coal gotta do with it? Went to chandlery by foot after phoning and they delivered by car. Only a mile but can't get there by boat because of the river raging along, and towpath all muddy and puddles, bit far with wheelybarrow. 3 bags coal, 3 nets logs. BSS..... FAIL!!! Passed 4 years ago with the same, but one BSS man's pass is another BSS man's fail. I don't disagree with the issues and will get to it as soon as I can: 1. Starter battery terminals all 'wonky'. Weird-looking things. 5.5 years ago the mechanic at the boat's old local boatyard said he'd do them differently. I thought - so why haven't you in all the past 6 years of the boat coming in here... BSS man told me what to do. I hate dealing with batteries, sparks always make me jump. BSS man can do it, says marina owner, if I can't. I shall have to sit and look hard at the terminals and use my brain. 2. Electric cables slung over the engine close to fuel filter and "could rub against sharp edges" - need to be sheathed / stuck in a tube of sorts. Simple. 3. Low pressure diesel pipe looks old and frail. Replace. About 15cm long. Just jubilee clips at each end. BSS man says he'll bring a length for us. Otherwise all OK. PASS certificate to be issued when faults corrected and inspected by same BSS man. Replacing battery terminals should be well within the skillset of an averagely competent boat owner. If you turn the isolators off then they won't spark but even if they do, it's 12 volts, you can't even feel 12 volts unless you have wet hands and even then it's hardly in electric chair territory. I had an advisory because of a fuel pipe likely to rub on a fuel filter, I just sliced a piece of rubber hose lengthways and slipped it over the pipe. Diesel pipe will be a doddle too if you know how to bleed it afterwards. When I had my BSS the deal was that if it failed the re-test would be free of charge, just the petrol money to pay.
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Post by TonyDunkley on Feb 24, 2020 18:26:58 GMT
What' s coal gotta do with it? Went to chandlery by foot after phoning and they delivered by car. Only a mile but can't get there by boat because of the river raging along, and towpath all muddy and puddles, bit far with wheelybarrow. 3 bags coal, 3 nets logs. BSS..... FAIL!!! Passed 4 years ago with the same, but one BSS man's pass is another BSS man's fail. I don't disagree with the issues and will get to it as soon as I can: 1. Starter battery terminals all 'wonky'. Weird-looking things. 5.5 years ago the mechanic at the boat's old local boatyard said he'd do them differently. I thought - so why haven't you in all the past 6 years of the boat coming in here... BSS man told me what to do. I hate dealing with batteries, sparks always make me jump. BSS man can do it, says marina owner, if I can't. I shall have to sit and look hard at the terminals and use my brain. 2. Electric cables slung over the engine close to fuel filter and "could rub against sharp edges" - need to be sheathed / stuck in a tube of sorts. Simple. 3. Low pressure diesel pipe looks old and frail. Replace. About 15cm long. Just jubilee clips at each end. BSS man says he'll bring a length for us. Otherwise all OK. PASS certificate to be issued when faults corrected and inspected by same BSS man. . . . . . . . . . . If you turn the isolators off then they won't spark but even if they do, it's 12 volts, you can't even feel 12 volts unless you have wet hands and even then it's hardly in electric chair territory. . . . . . . . . . This is an extremely irresponsible and dangerous piece of advice ! Lead acid batteries, and especially recently charged lead acid batteries, can give off and contain large quantities of Hydrogen in the cells. A spark from a terminal being connected or disconnected can cause this Hydrogen to explode, blow the top of the battery casing off, and shower you with the Sulphuric acid electrolyte.
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Post by Mr Stabby on Feb 24, 2020 18:33:54 GMT
. . . . . . . . . . If you turn the isolators off then they won't spark but even if they do, it's 12 volts, you can't even feel 12 volts unless you have wet hands and even then it's hardly in electric chair territory. . . . . . . . . . This is an extremely irresponsible and dangerous piece of advice ! Lead acid batteries, and especially recently charged lead acid batteries, can give off and contain large quantities of Hydrogen in the cells. A spark from a terminal being connected or disconnected can cause this Hydrogen to explode, blow the top of the battery casing off, and shower you with the Sulphuric acid electrolyte. Ok, so you wouldn't change battery terminals. Not much of a marine engineer, are you?
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Post by Gone on Feb 24, 2020 18:37:46 GMT
. . . . . . . . . . If you turn the isolators off then they won't spark but even if they do, it's 12 volts, you can't even feel 12 volts unless you have wet hands and even then it's hardly in electric chair territory. . . . . . . . . . This is an extremely irresponsible and dangerous piece of advice ! Lead acid batteries, and especially recently charged lead acid batteries, can give off and contain large quantities of Hydrogen in the cells. A spark from a terminal being connected or disconnected can cause this Hydrogen to explode, blow the top of the battery casing off, and shower you with the Sulphuric acid electrolyte. Agree, and even with the isolator turned off, if you short the terminals together with a big spanner, or if taking the positive terminal off first and the other end of the spanner touches some metal part of the boat, there will be a massive current with in worst case molten metal flying off the spanner. So don’t do it if you don’t know what you are doing.
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Post by TonyDunkley on Feb 24, 2020 18:58:51 GMT
This is an extremely irresponsible and dangerous piece of advice ! Lead acid batteries, and especially recently charged lead acid batteries, can give off and contain large quantities of Hydrogen in the cells. A spark from a terminal being connected or disconnected can cause this Hydrogen to explode, blow the top of the battery casing off, and shower you with the Sulphuric acid electrolyte. Ok, so you wouldn't change battery terminals. Not much of a marine engineer, are you? I conclude that describing you as Mr Shit-for-brains grossly underrates shit . My contempt for you is beyond words !
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Post by Mr Stabby on Feb 24, 2020 19:04:57 GMT
Ok, so you wouldn't change battery terminals. Not much of a marine engineer, are you? I conclude that describing you as Mr Shit-for-brains grossly underrates shit . My contempt for you is beyond words ! Aw diddums, are you still that pissed off with me agreeing with Ricco that it was time to get a proper engineer to look at his engine?
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