Autohelm Autopilot Mods

[Walt G.]

Hi. I'm looking for some technical advice on Autohelm Autopilots. I've installed a wheel model 4000 on my 37c, and it works fine. But it's noisy when it operates, and the noise is a nuisance sometimes. I know that a linear drive is avilable for the 4000, so my guess is that the autopilot brain is programmed to accommodate both. The 37c is a bit on the heavy side for the model 4000 linear drive, so I'm wondering if a below-deck-mounted linear drive for the model 5000 (or another one of Autohelm's linear drives) could be adapted to my 4000 in lieu of the wheel drive. Raytheon/Autohelm really wasn't of much help -- the just said that the higher-end linear drives were not designed for the 4000, not that they would or wouldn't work. CYA legalese, I suspect. It would be nice to be able to use the 4000 components if possible, so if any of you out there are electronic techs, I'd appreciate a response. Thanks. Capt Walt. S/V Moonshine.

 

[Ed Schenck]

Would not expect an answer...

to this one Walt. Because of your issue I have purchased, but not installed, the Simrad WP300CX. The 4000 was right on the limit for my H37C displacement. I'm afraid no one will venture a guess on adapting linear to the 4000, but maybe. I know I would prefer a linear actuator attached to the steering quadrant but for the $$$$.

 

[Patrick Ewing]

Autohelm is pretty arrogant but

you might be able to make it work if you can find someone who is electronically adept. I have had past dealings with Autohelm and their so called customer service and it isn't a pretty picture. They told me a variety of things at various times including:Autohelm doesn't use schematic diagrams, their parts are unique and irreplaceable from any other electronics supplier, and that they do not repair their control units to the component level - they simply change boards. I ultimately was able to repair my own old ST4000W with parts from Radio Shack for $1.99 in spite of the fact that the Autohelm service department told me that I could not do it. You will probably void your warranty but if you can wire up the controller to the actuator motor, it will likely be possible to make it work. I can't say absolutely for certain how to do it but the output of the controller is a simple bridge circuit using mosfet power transistors which control the polarity and voltage of the output to the motor. It is only two wires which connect to the motor and you just need to make sure that the polarity is correct. I do not know if your actuator requires some feedback circuitry but you may be able to simply ignore that. The other main issue is that the mosfets may not be able to handle the current of a larger motor but I suspect not. If you need more specific info, send me an email.Patrickpatrick.ewing@juno.com

 

[Ken Shubert]

Programming?

Seems to me that the controller should be programmable and allow you to take some of the work off the actuator. If you decrease the gain and increase the damping it should slow it down enough to reduce the constant dithering. I would bet that the "brains" are similar to my ST1000+ just because companies like to re-use circuits that work well. Does the actuator get hot, noisy, or stall, or does it just make you nervous? I'd probably have more confidence in a larger actuator but it might not be necessary.KenS/V Wouff Hong