[CA] [CA11] Type 3 Hydraulic Drive Thermal Overload

[rkupsaw]

Does the M81122 Type 3 hydraulic pump have a self-resetting thermal overload shutoff. Last summer I was on a 15 hour trip from Key West to Fort Myers FL (home). Two hours out of Fort Myers the hydraulic pump stopped working (the autopilot head worked fine just no pump response). I hand steered the last stretch but tried turning the autopilot back on several times with no pump response. A few days after I got back I went down to troubleshoot (?computer voltage output vs pump failure) and the system worked fine. It has continued to work fine on trips up to 3 hours. The pump is located in the starboard engine room of my sailcat. In the middle of the FL summer temperatures in the engine room are probably in the 110-120 degree Fahrenheit range (maybe higher). I've made several similar trips in the last 12 years without any problems. Is there a self-resetting thermal overload shutoff in the pump which could have accounted for this? If not has anyone dealt with a similar problem.

[Chuck - Raymarine - Moderator]

Welcome to the Raymarine Forum rkupsaw,

Q. Does the M81122 Type 3 hydraulic pump have a self-resetting thermal overload shutoff.
A. Raymarine drive units are not designed with a thermal overload shutoff. Instead, as drive units heat up, they tend to draw more power, which in turn will cause an over-current alarm to be triggered by the autopilot's Actuator Control Unit (ACU) / course computer. When such an event occurs, the autopilot's control head will alarm and provide a corresponding message. At that time, the autopilot will revert to Standby mode. Should no over-current alarm have been sounded, then it would be recommended the motor wires and connections / splices from the ACU / course computer through to the pump itself be inspected for corrosion or damage and to ensure that all connections are tight and promote good electrical continuity.

[rkupsaw]

Thanks Raymarine.

[Chuck - Raymarine - Moderator]

You're welcome.