Monday, April 2, 2012

Project ST5000: All buttoned up

Almost ready for the first sea trials. That picture shows the Benmar drive unit installed back in its place under the cockpit sole. The spare unit I used to do the prototype work is back under Jane's berth.

And I just received notice that a UPS package has been delivered - could it be the wire to hook up the compass?

Other than stringing this wire (never simple or easy on a boat), we are about ready for the first sea trials - without the rudder reference transducer. The autopilot will work without the rudder reference (see the St4000, which does not use a rudder reference), but it will work better with one.

Installing the rudder reference transducer will be nearly a project in its own right. Later.

Update:  For the initial sea trial, I will *not* permanently install the compass.  Instead, I will duct tape it to a suitably vertical surface in the cockpit.  That way I don't need to pull wire to do the initial testing.



Joe Okros said...

Well Done, I have a Benmar hydraulic pump, its a small reversible DC motor coupled to a pump via a chain. The controlling bits have been inoperable since I bought the boat, but I checked the operation of the motor by applying 12v and reversing it. It drives my hydraulic ram very nicely and draws about 3 Amps.

I was wondering whether you know if a St4000 can handle that amperage without relays? I also have a few wires going into the unit, presumably for stop switches etc (I haven't opened It),-I just disconnected the plug from the dc motor itself and applied 12v; measuring the current. I would prefer not getting too complicated.

bob said...

Hi Joe -

I do not have information on the current capacity of the ST4000+. And I'd be a little Leary of that 3 amp reading - it seems light. You need to design for worst-case conditions; with an electric motor, that means "locked rotor". I suspect that will be a lot more than 3 amps.

In any case, relays are air less expensive than a new ST4000...


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