Problems with Lenco actuator

[Berrymad]

Anyone else having problems with their Lenco trim actuators? The dealership changed all 3 actuators in May 2018 and the left trim actuator
just stopped working on my 2016 RZX. It sure is frustrating!!! Any tricks to extend the life of the actuators?

[IDBoating]

I heard a rumor that Lenco changed the seals and are having problems with water intrusion. If that's the problem, there's not much YOU can do to improve things. Hopefully they've got that sorted out and the problematic units are being replaced with corrected ones.

[bsreid]

Get new ones and cross your fingers

[chpthril]

Theres a very recent thread that shows some external difference between an older Gen actuator and the new Gen (new at the time of their posting) so one can see which actuators they have. Id start there to see which ones you got back in May. Either way, have your dealer order the latest Tige has from Lanco. I know its a pain, but its all there is right now. Tige and Lanco are working through the issue.

[bsreid]

You won’t be able to set it at 4 as they don’t engage unless you’re at 2300rpm. You can do dealer settings but then you’re just asking for trouble. The actuators get water in them, check connections.

[IDBoating]

I’m guessing the water gets into the actuators because over 500lbs of pressure is present at the actuators.

Unless Tige is buying some custom-designed actuator that is completely different from Lenco's standard mechanical design, the mechanical pressure on the actuator should not affect the degree of water intrusion. That 500 pound figure refers to how much pressure the actuator can exert, while water intrusion is controlled by the strength of the seals around the shaft.

Here's a little background that may help. The design of a Lenco actuator is such that it has three operational ranges: 1) Fully retracted, 2) Midrange, and 3) Fully extended. 1 and 3 behave the same, in the sense that when the actuator is at its mechanical retraction or extension limit nothing unusual will happen as the load increases until you reach the breaking point of the package itself. In other words, if the shaft is fully in or out, you can apply power in the "overtravel" direction and the motor will simply freewheel forever with no ill effects regardless of load until the stress literally breaks something physical. You cannot burn out the motor by attempting overtravel, the mechanism is specifically designed to tolerate the motor spinning when at either extent of travel.

Midrange, though, is different. When the actuator is NOT at either extent, your "500 pound" limit does make a difference if you power the motor. When the motor is off, the actuator will endure any load up to its physical breaking point. But if the shaft is midrange and you apply power, the motor WILL attempt to move the shaft. If the load is light enough, the shaft will move (normal operation). If the load is too heavy, the motor will still attempt to move the shaft but since it cannot turn against the excessive load, the motor appears as a dead short and you'll pop a circuit breaker or fuse (and some of our tests suggest there is also a self-resetting overcurrent cutout in the actuator body itself). The important point here is that this is entirely controlled by the mechanical load on the actuator.

Now, relating this back to water intrusion... while all of the above is going on, there is a seal between the actuator housing and the chromed shaft, just like the seals on hydraulic cylinders found on construction equipment. That seal is rated for some PSI rating, and as long as the differential across the seal is below that number, no water will flow past the seal. But the PSI of the water has basically nothing to do with the mechanical load on the actuator... just as the typical atmospheric pressure around your body (14.7 PSI) doesn't change just because you're lifting something heavy. You might be working more, and breathing harder, but the differential pressure across your eardrums doesn't change.

Things that DO affect the seal include depth in the water (the deeper you go, the higher the water pressure) and the direction of hull travel (if the seal is facing into the oncoming water on a boat traveling 30-40 MPH, that's a LOT more pressure). Obviously for a wakeboat application, water depth really isn't an issue. And since most actuators are behind the transom, most of them don't experience the "head on" pressure of oncoming water either.

All of this adds up to what was mentioned earlier: It appears Lenco "changed something" and that new something isn't working as well as their old solution. I don't know the specifics... could be the parts are the same but they're being assembled wrong, or they changed the design and didn't test it enough, or a vendor changed something without them knowing (example: an unannounced change to the seal material). Lenco has been at this a long time, so I'm confident they will sort it out, but that means there will be a "bad batch" of actuators circulating around the market for a while. Hopefully they'll publish the range of affected serial numbers so they can be changed out.

EDIT: I thought of one case where the mechanical situation might affect the seal: Side loading. Actuators are supposed to have their loads perfectly axial, e.g. in line with the length of the shaft. But imagine fully extending the shaft, and then pushing against the side of the shaft end really hard. You'll shift the shaft "sideways" in the housing to at least some extent, which will put more pressure on one side of the annular seal... and REDUCE the pressure on its other side. The seal expects to have roughly equal pressure against the chromed shaft all the way around, but if the shaft is side loaded as described the side of the seal toward the side load will probably have less PSI resistance. If the layout of the mechanism is such that the actuator experiences high side load forces, this could permit seal failure and water intrusion. Moral of the story: Don't side load actuators, instead design a linkage of some kind that takes the actuator's linear force and translates it to whatever direction is needed.

[IDBoating]

My Lenco actuators are wired directly into the PDM, which I believe provides overload and short circuit protection an indefinite amount of time. A motor load looks very similar to a short circuit based on the low resistance of the actuator motor. Obviously not exactly, or the PDM would never allow the actuators to function.

Technically, a motor looks like a dead short until its armature starts to rotate, which generates back EMF that resists current flow. The PDM tolerates this for a short (no pun intended!) period of time, otherwise you're correct the actuator would never move. BTW, our own tests have shown that actuators can have peak inrush currents exceeding 70 amps (!!!).

This is why the Murphy controller is programmed to overdrive the actuators to the home position.

I suspect the reason is because - for some unfathomable reason - electric actuators do not have integrated position sensors. And just exactly like using timers for ballast, using timers for actuators is error prone... and the longer you do it without rezeroing, the more accumulated error you get. I suspect they take every opportunity to recalibrate their idea of where the actuator REALLY is because, seriously, it's never better than an educated guess.

I think size of surf plate, angle of surf plate and design of surf plate does affect how much force is applied to that actuator, as the center plate malfunctions alot less when ballasts are empty and surf plates are fully retracted, under any speed.

You're absolutely correct, all of those things present not just a load, but a VARYING load. Another reason why timers are such a terrible idea for measuring actuators. Just like ballast, there are all sorts of variables that timers do not take into account. What if the boat is moving, or not moving, or moving fast vs. slow? What if the engine is running (higher alternator voltage makes the motor turn faster) or not (lower battery voltage makes the motor turn slower)? What is the effect of more vs. less ballast today? What was the starting and ending angle of the plate? Now combine all of those factors together... what the heck REALLY happened when you ran the actuator for, say, five seconds? It will never be the same twice!

Is it possible Tige is fighting a bad surf plate design and Lenco a bad actuator design?

Dead reckoning actuator (or ballast) condition based on timers is a bad idea, but Tige and everyone else is stuck with it because like I said, no one makes sensored electrical actuators. As for the original question of this thread, I've heard the water intrusion problem is a temporary one based on some sort of change at the Lenco factory. I'm confident that one will be solved.

Or was the wrong actuator selected for this application. What would happen if Hydraulic vs electrical actuators were used, I’m guessing all actuator issues would be solved.

Bennett makes hydraulic actuators that DO have positional sensors built in. My 2009 Tige has a Bennett actuator for its (single) TAPS plate and it has a sensor. I have no idea why neither Lenco NOR Bennett put a sensor in their electrical actuators, but they don't. There's a third brand of electrical actuators out there too, I can't remember their name right now, but they too don't integrate a sensor. It's bizarre. The industry knows that sensors would solve lots of problems, and they have experience with sensors (at least in the hydraulic actuators), yet this problem has existed for years without solution.

Sure, any actuator with an integrated sensor - regardless of electric or hydraulic - would solve the positional accuracy problem. Malibu solved this by dropping Lenco and going to an actuator made by Parker that does have an integrated sensor for their SurfGate application. Parker's units are significantly more expensive (like 2-4X) so the fact that Malibu would spend that money tells you how important it was for them to solve this problem. But not all boat manufacturers see it that way... we prototyped an actuator control module over a year ago that provided accurate position for standard Lenco and Bennett actuators but the boat manufacturers we demoed it to told us they didn't think the errors were serious enough to spend extra money to solve. So we shelved that project, no sense in finishing technology that nobody wants to buy.

Bottom lines: 1) It doesn't appear the industry thinks the actuator positional errors are serious enough to care about, and 2) your water intrusion problem is a temporary manufacturing problem that will eventually get solved.

[IDBoating]

I would be interested in the Lenco designed amp draw of the actuators vs the max current allowed by the PDM.

See my response, above. Peak inrush (startup) current can exceed 70 amps, but only for a very short time, and the PDM's are tolerant of that.

I also think the actuators seals are failing. Is this due to poor design or overloading the actuator?

A bad design choice or a production problem. As I described in my earlier response, axial loading should not affect the shaft seal. SIDE loading could affect it, but if that were the reason then it would be Tige working on a solution - not Lenco. It would be due to Tige's application applying too much side load to the actuator. Since the rumors I've heard say Lenco is working on it, my best guess is "design choice or a production problem". They'll figure it out, this isn't their first actuator design {grin}. This sort of thing often happens when someone decides they can save a few cents by going with a cheaper material or process, only to find out that there was a reason the old approach had been working for so long.

[Berrymad]

I just changed out the lenco actuator myself and found something interesting. I took the actuator off and the trim tab itself was stuck in the retracted position. I put quite a bit
of force on it and got it to move and after applying WD40 to hinge got it to move freely again. I then tested the actuator and the motor inside ran but there was no movement
of the actuator itself. I have not to my knowledge hit anything with the tab and there is no visible damage to tab. Has anyone ever had the trim tab freeze up like this one? And
is there a lubrication or service that needs to be done on the tabs? Im assuming that my problem wasn't water getting into the lenco actuator

[IDBoating]

I then tested the actuator and the motor inside ran but there was no movement of the actuator itself.

Did you try running it both directions (by reversing the leads)? Could be that it's just at one extent of its travel, in which case the motor turning but the shaft not moving is entirely by design.