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[toot toot]

hi all from down under, i'm presently converting my static anchor winch on my supply ship ,which is scratch built , to mechanized. i have made the above deck section as a rotating shaft with dummy drums and looping the anchor line over and under the deck to a servo that ive made continuous rotation with the pot still in tact, so i can pay out and winch in with a sort of speed control,but my delemer is sometimes it creeps a little when I'm not watching and i don't want it to stall out or worse, snap off my anchor so I'm wondering ,i know its a long way to get to the question ::), but can i isolate the power to the servo by putting a switch in line with the red servo wire ,power , so that when Ive finished winching in, when i break that switch, it will stay where i put it.  does that make sense.
great site , although Ive been reading for ages, have only just joined lately, so thanks for a great read also,

cheers Chris.

[catengineman]

Hi toot toot,   Yes in a word,

I tried it that way and it worked but be prepared for some clitching (I had some problems)

Another way is to remove the internal speed control and use a designated one with a definite zero at rest/stop/center.

I have mine control either the bow thrust or the anchor winch via a servo controlled selector switch.

R,

[toot toot]

i didn't want to remove the pot as I'm sure the anchor would slam home and bust something, so the speed control part was handy, but i like your idea on the bow thruster controller to do it , as it is , I'm putting a bow thruster in at the moment as well ,not that it needs it as she turns on herself already with a reversing switch on one motor.do you have a wiring plan for such a job,as i  think i have a spare micro switch available on a spare channel.sounds like a plan

cheers Chris

[Martin (Admin)]

I'm sure the electronic geniuses on this form can point you to a current limiting circuit or a self reseting circuit breaker type thing or a drop out relay........

[malcolmfrary]

Modifying the servo by having the works operate a pair of relays via diodes and having the relay contacts work the servo motor is simple enough, but sensing when the anchor is fully wound in before damage occurs is less easy.
Inspecting a dead walkman or other cassette player might reveal a usable slipping clutch in the area of the take-up spool. 
Sorry nothing practical, just thinking aloud.

[catengineman]

A quick drawing of my old anchor winch with its own slip clutch idea

[Weeds]

1 please post a how to of your servo hack
2

to a servo that ive made continuous rotation with the pot still in tact

to make servo rotate SLOWER, replace servo motor with a larger sized motor.

[toot toot]

hi , hey weeds, i got the hack plan from on here somewhere ,all i did was to
pull the top of the servo off
lift off the final drive gear ,and snip off the little lug that stops it against the the other pot,and grind it flush
run a same size drill bit up the inside of the gear just enough to remove the drive dog casting but not go too far to loose the horn attach thread.
now what I'm going to do is plug it all back in,
now when toy move the stick ,you have it .
next though you need to centre the pot so it will stop when the stick is in neutral, by just turning the knob until it stops, its very touchy.
I'm thinking a drop of super glue to stop any chance of it turning whilst in use,
then reassemble the final gear back on and your away.

thanks catengineman,does the slipping happen by the end nut tension.may give that mod to my drum a try.

with the anchor sensing when its home, i have a idea i might try, but originally i was just going to watch it till it was there , which is why i wanted it to go slow, and especially not creep any further.i might try putting the switch in line to isolate it when its home as its only a servo on 5 ish volts

[catengineman]

My slipping clutch is from the friction between the brass tube and the rubber pipe with the aid of some silicone grease, adjustment is via the first nuts on the shaft if that is any help.

I watch to see it go home and then turn the switch to either off or bow thrust, well you would not need to thrust as well as anchor would you.

R

[toot toot]

yep, clear as mud thanks, i had a fiddle with both using the in-line switch and by the bow thruster speed control, and they both have their merits,the servo version is a little slow,but simple, but i have to use a slow 12v motor with a 4/1 worm drive to get the other option to drive slow enough ::)just need to find one of those 6 pole thingies.either way i will use my spare micro switch to swap either options.thanks also for the clutch details.
cheers 

[andrewh]

TT

You can combine these bits of wisdom, as if it wasn't interesting enough!
The servo in you first post was slipping slightly since A) modified servos have wickedly small "off" bands* and B) the gear ratio is high, but not completely irreversible, so it does.
*the off band of the modified servos is very voltage-sensitive - and wanders as you turn on and off other things in the boat

The servo electronics can be connected to a small worm-drive motor - and this will be COMPLETELY" irreversible (but the servo can still creep backwards if the neutral wanders)

andrew