Mechanical Linear Actuator Specifications

[Phil Niles]

Hello,
I'm in the market for an electric linear actuator. Can anyone tell me how Ray's specifications for listed torque relates to the the listed peak thrust. Example the type 2 short and long linear actuators M81133&4 state a peak thrust of 480 kg (not kponds) but have different torque figures (1190 & 1660 N m) respectively. The only difference is actuator stroke. Are the Torque values given meant to be max values delivered to the rudder by the actuator or by rudder lift to the rudder stock?

Thanks for any help

Phil

[Chuck - Raymarine - Moderator]

For the benefit of others who may view this thread, torque refers to a rotational force, whereas linear drives exert force in linear fashion (i.e. thrust / extraction). The force exerted by a linear drive specifies the amount of force which will be exerted by the drive's ram when pushing or pulling. When attached to the boat's tiller arm or quadrant which is in turn attached to the rudder post, the linear drive will exert a rotation force on the rudder post. This rotation force will be equal to the specified force of the linear drive multiplied by the length of the tiller arm.

Example: Given that the Type 2 Short linear drive exerts a force of 480 kg and should the tiller arm be 10" (25.4 cm) long, then the torque exerted on the rudder post would be 480 kg x 25.4 cm = 12192 kg - cm. Should you need to convert kg - cm to N-m (or other units), there are web based utilities such as the one found here which may be used to do so. In this case, the maximum torque exerted to the rudder post would be 1195.6 N-m. The Type II Mechanical Linear Drive is designed for use with a longer tiller arm. Given that the Type 2 Long linear drive also exerts a force of 480 kg and should the tiller arm be 14" (35.56 cm) long, then the torque exerted on the rudder post would be 480 kg x 35.56 cm = 17068.8 kg - cm, or 1673.9 N-m. As you may see, the listed maximum rudder torque values for the Type II Short and Long Mechanical Drives are very close to these calculated values.

[Phil Niles]

Got it. I reviewed the install manuals for the actuators and discovered the two suggested lever arm distances. I'll pick from the two actuators based upon quadrant lever arm distance and resulting quadrant rotation (long vs. short throw).

Thanks for your help Chuck.
Phil

[Chuck - Raymarine - Moderator]

You're welcome.

[Phil Niles]

Hello again Chuck,
Another question about actuators, specifically parts. I have located a used Type 2 short actuator that appears to be an earlier vintage model. The wires appear to exit the case on the side as opposed to the end plate. Are parts still available to refurbish the units?.

Phil

[Chuck - Raymarine - Moderator]

Phil,

Unfortunately, Raymarine no longer has parts for the specified mechanical linear drive and can no longer offer service for these drives.

[Phil Niles]

Thanks Chuck

Phil

[Chuck - Raymarine - Moderator]

You're welcome.

[Phil Niles]

Hello Chuck,
Is there a way to decode what appears to be a S/N on the side of a type 1, 12" throw actuator. My concern is centered on replacement parts being offered for this unit. I believe it to be a P/N M81130 however there is no reported P/N on the unit other than what could be a S/N stated to be 0490068.

Thanks for any help

[Chuck - Raymarine - Moderator]

Welcome to the Raymarine Forum Niles,

Raymarine's current serial numbering format is MMYNNNN, where
- MM: month of manufacture
- Y: year of manufacture ... at the time of this response, 9 would indicate 1999 or 2009 as the month of manufacture
- NNNN: nth unit of the total number of units produced during the month