Electro magnet for autopilot drive (Cetrek) on Princess 37

[markdj]

On a Princess 37 there is an old Cetrek autopilot which is attached to the steering with a cable that goes into a steering column that is attached to a motor with a chain drive.

When the autopilot is not in use the shaft of the motor can turn so as to allow manual steering but when the drive is engaged an electro-magnet is engaged that pulls a clutch plate which holds against a bearing with a friction type/brake pad which should hold the clutch plate in place to prevent slippage so to allow the motor to turn the steering.

The electromagnet seems to have lost its strength and the drive is slipping. The magnet is made by Eaton.

A new cable drive is £900 so I was hoping to avoid replacement. I have tried replacing the brake pad with a new one as the old one was well worn but this has not helped increase the friction to allow the drive to work without slipping.

Does anyone know where I could get a magnet for this or have one lying around ?

The drive unit is a 402/12v

Thanks

 

[William_H]

Electromagnet

It is unlikely that the electromagnet will lose it's power. generally they either work at full power or not at all.
I would suggest that it may not be getting full 12v power because of bad contacts or bad wire. You could check for 12v at the coil or even provide additional wiring straight from the battery to the coil to confirm the coil (electromagnet) is good. You might also look for dirt or corrosion that might inhibit full motion of the armature. (the moving part) if all else fails you may be able to bodge fit an electric clutch from a car aircon compressor. good lcuk olewill

 

[cimo]

hello mark.
a known problem apparently (although I know nothing about them).

have you tried Stephenson Gobin?

http://build-a.com/ts/jamesbushell/Links.html

(thinking out loud, I'm wondering why an electromagnet clutch ).

 

[Graham_Wright]

I know nothing of the application but a "stop" solenoid might be suitable. Available on eBay for diesel engines but check it is push or pull to suit.

 

[markdj]

Thanks for the advice, I will try your suggestions.

 

[jackho]

I think I have what you describe although the motor drive is a Lewmar branded. Mine failed eventually after becoming unreliable - the wire into the electro magnet broke - replacement was over £300 so dug out a bit of the winding and re soldered. Having said all that there is an adjustment to set the clutch/magnet interaction which might be your problem as there is nothing else in the electromagnet to fail.
hope this helps. Jackho