Re: Bow Thruster won't come up

Duane Siegfri

I received the new limit switch today and still no joy.  

This is confusing since, in diagnosing the problem (bow thruster would not retract), I borrowed a new limit switch from another Amel SM  (JOY), put it in the lowest position on the Actuator (marked "H") and the Actuator was then able to raise the bow thruster to retract it into the hull.  From this I assumed the problem was the limit switch.

Okay, so I get the new switch and install it in the "H" position (lowest on the actuator tube).  With the new switch in place I tried to lower the bow thruster motor.  The lights on the "SP" and "B" switches lit up, but the actuator motor did not engage.

I switched the toggle switch at the helm to the "UP" position and the lights on the "SP" and "H" switches lit up, and the up buzzer sounded.  This seems right since the thruster motor was "UP". 

I replaced the "B" switch (the upper position on the actuator tube) with a new one, and repeated the procedure above with the same results.

I'm starting to wonder if the actuator motor is burnt out, so tested the motor wires for continuity through the motor and got continuity.

-What else could I test?

-If the actuator motor was not working it would explain the current situation, how do I test the actuator motor?  And, if it's shot, why did it work to raise the thruster motor with the borrowed switch?

-What does it mean when the light on the limit switch comes on?  I find it odd that the "SP" limit switch light comes on when the thruster motor is all the way up.  I tried to activate the thruster prop in this position and it did not activate.  From that I assume when the limit switch light is on, the motor is locked out.  The old switches were marked with a "Normally Closed" icon.

-Which switch controls the limit of the bow thruster motor up and down?  Is the "B" (on the top of the actuator tube) the limit switch for the down position for the thruster motor?  And the "H" switch (on the bottom of the actuator) the switch for the "UP" position of the thruster motor?)

-I don't understand why with the bow thruster motor up (and you get no movement of the thruster motor):
When you toggle the actuator for "UP" the switches look like this:
SP (lit)     B (not lit)

H (lit)

When you toggle for "Down" with the thruster motor up you get this:
SP (lit) B (lit)

H(not lit)

Any ideas out there?

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