Is this 12V solenoid continuously rated?

[Anonymous]

I am reading 18 Ohms which is a little higher than yours. But still 'only' 12W. Mind you, 12W is not inconsiderable, especially in a small package with high contact amps and a hot climate. This data sheet states that it is continuous - I think they must all be for this application. Many thanks.

 

[ean_p]

Google for 'Albright' who make very excellent contactors for use on DC systems and as 'Line' contactors and so are energised for very long periods. In addition they are supported by a full range of spares etc so are fully sevicable over time. Standard fit on most British and German electric industrial handling equipment.

 

[Guest]

I did not realize Lofran ran three wire split motors. Two wire motors are much easier. Yes, the solenoid box has to be at the bows in your case.

You could get around this with a large diode splitter but that would just add more voltage drop.

You can still do the other idea about the pneumatic overriding the remote by using a DPCO relay but it would involve cutting the pneumatic pipe.

Would your remote be running off the same leads as driving the windlass. In near stall conditions the voltage at the far end might be a little low and noisy. The remote base unit should be located away from the windlass. That is why I first suggested the other way around. You will have to find some stable power feed at the bow.

"The receiver feed must be separated from the windlass feed, as this is subject to high voltage drops"

 

[Guest]

"The penny has just dropped."

Yes, but mine came down with a bug thud. Sorry.

Lewmar use all three methods, 2 wire, 3 wire and some with the contactors built in. 3 wire makes the contactors cheaper.

 

[Anonymous]

We're singing from the same hymn sheet, now. Since the discussion has widened and is of general interest, I'll discuss here how I am dealing with the local supply for the wireless electronic module.

In the anchor locker, adjacent to the modules, I am fitting a small sealed lead-acid charged by a cheap laptop dc-dc convertor. I am arranging the output of the convertor to appear as a constant 14.2V across the battery when the battery is fully charged and when the windlass is not running. I haven't bought the laptop supply yet; if I can get inside it I will set it to 14.2V, if not I will use diodes (silicon and Schottky) to adjust the voltage from the 15V setting. It doesn't matter if the converter drops out while the windlass is running as the battery will be providing the supply. Actually, the convertor will almost certainly be rated for more than we need (we need less than 2A) and there is a very good chance that the convertor will run perfectly happily at around 9V which is what we will probably have at the end of those long leads at full load. However, that would be bad design and would be likely to fail when we need it most - i.e. we are struggling to get the anchor up in bad weather and a difficult bottom. At the small extra cost of the battery, we will avoid that risk.

Many thanks for your input /forums/images/graemlins/smile.gif

 

[pvb]

There\'s a much easier solution...

Gosh, you seem to be making heavy work of this! There's surely a much easier solution - simply replace your pneumatic footcontrol with a plain waterproof footswitch (Lofrans sell them cheaply). This would feed low current 12v+ to the "Up" control terminal of the control box. It would work independently of the radio control. You could even have 2 footswitches, one for Up, one for Down.

You could then get rid of the pneumatic switch itself. You wouldn't need a second switch in the anchor locker. You would still have on/off control of the windlass power from the instrument console.

Even simpler would be to dispense with the solenoid and leave the windlass power connected permanently. It presumably is protected by a breaker, so what's the problem with leaving it energised? Mine's wired this way and has worked fine for years.

 

[Anonymous]

Re: There\'s a much easier solution...

Maybe I am missing something but I don't see how that 'simplifies' it other than by removing the (existing) complication of the pneumatic arrangement. What you are suggesting is using a proper foot switch in place of my simple toggle switch hidden in the anchor locker, if effect, where 'your' foot switch controls the windlass whereas in the existing proposal the pneumatic switch controls it (using pre-existing circuitry). It is certainly worth considering, I hadn't thought of it. I would not entertain drilling any more deck holes so I would have to change over the pneumatic if I were to follow your suggestion.

I have often wondered why people use pneumatic switches; I presume that experience has shown that ordinary switches are unreliable? Otherwise why go pneumatic? Since the boat wiring diagram shows the present pneumatic arrangement my proposal just piggy-backs onto the existing scheme on the drawings so that has a small benefit. Also, the cost of a Lofrans foot switch isn't insignificant.

I wouldn't leave this radio system powered up 24/7/365 and available to drive the windlass - we liveaboard and are in marinas for 6 months of the year and I think the risk of unwanted operation is too great. It's a heavy bit of kit and I like to know that for the windlass to operate current has to flow through a set of manually-operated contacts. In my present set-up there are two such contacts; the anchor switch on the control console and the pneumatically-operated switch. I want to retain that degree of interlock.

While sketching out the circuit to muster and order the parts, I decided that the laptop converter scheme is far too overcomplicated. I am replacing this by a couple of relays and some simple diode logic to shunt the local lead-acid straight across the two power leads when the system in enabled but when the windlass is not actually running. I've got all the bits on board and it should work fine.

Many thanks for your help, it is appreciated /forums/images/graemlins/smile.gif

 

[pvb]

It simplifies it because...

It simplifies it because (a) you remove the potental for a leak in the pneumatic tube, (b) you remove the pneumatically-operated switch, (c) you remove your additional switch in the anchor locker. It just increases the intrinsic reliability of the system.

As for your view that "the cost of a Lofrans foot switch isn't insignificant", I don't think £12.95 is a lot for a waterproof footswitch.

 

[Anonymous]

Anchor Windlass controls

But it makes the project more complicated and expensive, without a doubt. Interesting as a digression, are waterproof switches more reliable than pneumatic? Why would anyone fit a pneumatic unless there was a (perceived) benefit?

As for the intrinsic reliability, if you leave the two existing power leads powered up 'constantly' as you have suggested then there is a greater probability that the windlass will operate. On the other hand, there is a greater risk of false operation. The probability of failure in either design is acceptably low, I think, and the reliability of both methods is an order of magnitude better than the windlass motor, gearbox, etc. In any case, it is possible (albeit it slow and tedious) to bring the chain up with the manual ratchet so the safety of the vessel does not depend on it.