This forum uses cookies
This forum makes use of cookies to store your login information if you are registered, and your last visit if you are not. Cookies are small text documents stored on your computer; the cookies set by this forum can only be used on this website and pose no security risk. Cookies on this forum also track the specific topics you have read and when you last read them. Please confirm whether you accept or reject these cookies being set.

A cookie will be stored in your browser regardless of choice to prevent you being asked this question again. You will be able to change your cookie settings at any time using the link in the footer.

Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
hydraulic pump - convertible top- replacement for linear actuator
#1
Hello,

i have a Searay cabin cruiser with hydraulic steering (Mercruiser outdrive) and a sailboat with tiller steering to upgrade to Pypilot.
Poked around for hydraulic pumps and noticed how insanely expensive these are, like everything marine-related right...?

I used to work as a certified automotive master mechanic in a previous life and thus was thinking about what off-the-shelf auto components could replace such an autopilot pump, realized convertible top pumps could do the trick.  

In order to experiment with this I just bought this unit (1994-1998 OEM Ford Mustang Convertible Top Motor Hydraulic Pump Cylinders ) with hydraulic hoses and cylinders of eBay for 150 bucks, if it does not work I have other uses for it.

Thinking about putting this into the existing hydraulic circuit of the Searay and also building an hydraulic version of a linear actuator to work on that sailboat.

Has anyone experimented with this setup in the past?
In any case, I will keep my progress posted here.

[Image: s-l1600.jpg]
Reply
#2
Interesting, curious how you get along with this. I only see two wires coming out of the motor, so can I assume it is a reversing motor? Does it pump in both directions? Not sure how you will use both cylinders? Stern drive steering is a bit of a mystery to me, my friend asked me to install Pypilot on his stern drive, and I was quite surprised to see cable steering from the helm but yet it had power steering... basically from the engine power steering box, the cable just opened a valve one way or the other... quite intriguing, but I still am not sure how I will use this with pypilot...
I currently use a hydraulic pump for my 200Hp outboard on my 22' WA fishing boat https://www.seatechmarineproducts.com/se...r-min.html
It works fine, and you can find them on sale periodically. I have an axillary motor 15hp I use for slow trolling (fishing) which I also control with pypilot, but for this I use an electric linear actuator.
Reply
#3
yep, its a reversing motor pumping in both directions. I will remove one cylinder from the set thus doubling the speed of the remaining one. An you are right regarding the sterndrive as well, i figured just because it has powersteering that it is all hydraulic, but mine also has this cable coming from the helm.
I will look into connecting the convertible top hydraulic cylinder in parallel to the power steering cylinder of the outdrive, before the valve where the cable connects.

ill keep progress posted
Reply
#4
you could also put the cylinders in series for more range, or parallel for more power maybe?
Reply
#5
You are right, i was thinking about that as well. I tested the system yesterday, it draws about 20Amps during operation, pistons move quickly, about 1 inch/second. Did not measure stall Amperage yet, because meter maxed out at 30 Amps.
I am not sure what the limitations for the high amp controller from the store are. Do I risk to burn it if stall Amps are to high?
Why has it been removed from the store?

Edit, I just read through the documentation that Jean provided, seems that 20Amps is the max for the high power controller, so this pump will push the electronics to the limit, probably not the way to move forward. Especially since the stall Amps seem to be higher than 30Amps.
https://pypilot.org/schematics/highpower_datasheet.htm
Reply
#6
You won't burn it out. There is overcurrent, overtemperature and a fuse. What will happen, is, it will stop working until it cools, or for large overloads, it will throw the overcurrent protection. For the regular controller if you tried to use it, you would either trip the over current or blow the 10 amp fuse drawing 20 amps in general use most likely.

The high current controller supports up to 30 amps not 20. It is ok if stall amps is higher (up to 50 amps) It is removed from the store because I can't produce enough of these (not enough time) but also a lot of basic parts are not available anymore. This requires redesigning. After a redesign I have to build just 2, and ensure the new design is good, and hopefully by then I can get more. I made a new design a few days ago...

The way things are going, more items will be removed from the store in the future as many parts are simply out of stock with no indication they will be back anytime soon.
Reply
#7
(2022-02-03, 06:43 PM)seandepagnier Wrote: You won't burn it out.   There is overcurrent, overtemperature and a fuse.   What will happen, is, it will stop working until it cools, or for large overloads, it will throw the overcurrent protection.   For the regular controller if you tried to use it, you would either trip the over current or blow the 10 amp fuse drawing 20 amps in general use most likely.

The high current controller supports up to 30 amps not 20.    It is ok if stall amps is higher (up to 50 amps)    It is removed from the store because I can't produce enough of these (not enough time) but also a lot of basic parts are not available anymore.  This requires redesigning.   After a redesign I have to build just 2, and ensure the new design is good, and hopefully by then I can get more.   I made a new design a few days ago...

The way things are going, more items will be removed from the store in the future as many parts are simply out of stock with no indication they will be back anytime soon.

There must be a small reservoir in there somewhere?  I'd like to see the hydraulic schematic for this system if you have it?

Thanks
Jason
Mechanical Engineer (Hydraulics)
Reply
#8
(2022-02-06, 03:38 AM)Techstyle Wrote: There must be a small reservoir in there somewhere?  I'd like to see the hydraulic schematic for this system if you have it?

Thanks
Jason
Mechanical Engineer (Hydraulics)

Based on your signature.. you would know better than I. Yes there is normally a reservoir connected to a third hose from the pump but it all depends. I am not familiar with that specific pump in the image.

I simply provide electronics capable of driving a reversible motor which turns the rudder both ways. It can drive an electro-mechanical or hydraulic pump: it doesn't know the difference. The actual hydraulic schematic can vary depending on the specific boat. There are multiple ways to configure it, especially with multiple helms, pumps, and even strange home-made bypass valves giving helm feedback, or not.
Reply
#9
(2022-02-06, 09:20 AM)seandepagnier Wrote:
(2022-02-06, 03:38 AM)Techstyle Wrote: There must be a small reservoir in there somewhere?  I'd like to see the hydraulic schematic for this system if you have it?

Thanks
Jason
Mechanical Engineer (Hydraulics)

Based on your signature.. you would know better than I.   Yes there is normally a reservoir connected to a third hose from the pump but it all depends.   I am not familiar with that specific pump in the image.

 I simply provide electronics capable of driving a reversible motor which turns the rudder both ways.  It can drive an electro-mechanical or hydraulic pump: it doesn't know the difference.  The actual hydraulic schematic can vary depending on the specific boat.   There are multiple ways to configure it, especially with multiple helms, pumps, and even strange home-made bypass valves giving helm feedback, or not.

Looking at it, it looks like the two cylinders both extend when run one way - which is typical for the convertible top but probably opposite to what you want for rudder/outboard control, depending on how you configure it.  If they are opposite (one extends, the other retracts) then the volume of oil displaced is equal and therefore the reservoir is just to make up any losses, but if the cylinders are both extended then the oil required in the reservoir will be at least the volume of both the rods.  

It is probably best to use both with the head of one and the rod side of the other connected together so you don't have to size and install a significant reservoir.
Reply
#10
Hi,

I have sort of the same problem question. I want to add pypilot to my existing hydraulic steering. 12V hydraulic pumps are very pricy.

My situation
I have an catamaran with hydraulic steering.  The steering wheel is the hydraulic pump with built in reservoir. The rudders are connected via a tiller. A hydraulic ram is mounted to that tiller.

I want to make it like the Schema below (withouth part 3). 
[Image: groupe_electrovanne_simple_com.png]

I want to buy a trailer hydraulic pump like this which is reversible and made for trailers like the picture below. Those units are 300 euro's. My questions are:
Is that feasible and do i forget something?
Can pilot just control the buttons via a relay or directly? It will be on 100% always then. 
Do i need check valve's so that the fluid wont spin the when when the auto pilot is working?


The motorpower is 1.6kw Rated and 3.0 kW max. @12V that is 133/250  Amps. Wonder what the true power draw is for my small cylinder.
I don't like the large fluid container, I want to try to get rid of it since there is already a fluid tank in my wheel. 

[Image: VEVOR-Car-Jack-Hydraulic-Pump-12V-DC-Dou....jpg_.webp]


Now, another option is to use a more regular hydraulic pump like this one: https://www.cactusnav.com/universal-auto...22520.html
That does require a motor driver, but I have to find out the amperage of te system.


Thanks in Advance.
Reply


Forum Jump:


Users browsing this thread: 1 Guest(s)