Designing a new controller for Dolphin Advantage

by jason
(seattle washington)

Like a lot of others have posted here, my mom's dolphin advantage has quit working. The unit will run for about one minute and then stop. It will not restart until the power supply is shut off for about 5-10 seconds and then turned back on. It then runs for about a minute and shuts off again. A good friend of mine repairs cnc equipment and we are designing a new controller for this to eliminate all of the circuitry and complications inside the motor box.

I never paid much attention to this thing when it worked properly and had a couple of questions as to it's operation. The drive motor I noticed runs at two speeds. What is the reason for the slower speed? Does it do this when it is climbing the pool walls? I also noticed that the propeller that moves the water was delayed in starting when the unit is initially powered up. Is it supposed to always run after it comes on?

Somewhere I remember seeing it advertised that these pool cleaners average about fifteen cents per cleaning. My mom does not feel that she got her money out of this thing in that regard. Judging by some of the other comments here, I think that she did much better than others. I cannot say as I have only used her pool about 3 times since she bought her house. Spent many a time helping with the cleaning and maintenance though. :)

ADMIN REPLY: The motor runs forward and backward. When you have the controller up and running I will advertise it here!

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Oct 11, 2021
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starstarstarstarstar 		switching direction at the power supply
by: Mike

I'm very late to this conversation, but I want to add a note for anybody else interested.
At first I liked the idea of adding a current switcher inside the power supply, since that would simplify maintenance and let the track motor change directions. But, that means the pump motor with the little fan will also be reversing direction. So it will be blowing the water in the wrong direction half the time.
Maybe there are more tricks to make it work, but nothing was mentioned about it.
Sep 26, 2014
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starstarstarstarstar 		Two speed question
by: Steve Hobrecht

The original design (I have rev 03 on the PC board) uses an Atmel 16 bit microcontroller. The microcontroller can be used to provide a PWM (pulse width modulated)signal to the tracking as well as the fan/pump motor. This can, as your designer can attest, provide any speed from 0 to maximum to the track motor driving unit.

My unit is also broken but I an electrical engineer with 35 years design experience in the area of Analog and power management, exactly the experience that Maytronics should have availed itself to many years ago.

The Atmel microprocessor (uP) initially does a motor check, monitoring the current supplied to each motor using sense resistors in the ground return of each motor circuit. If these checks fail, the uP can then, if it finds a fault, turn on M3, a Siliconix dual DMOS (Si4946) through R31, a low valued power resistor, to overload the external power supply that, in turn shuts itself off seeing the high current drawn by M3. The external power supply keeps the Dolphin shut down when line powered and even after due to the storage capacitors inside the main power supply. This is why it takes a while before you can restart the unit after the AC line is removed.

I, also am looking into redesigning the electronics using what Maytronics did correctly and changing what they did incorrectly.
Sep 12, 2012
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starstarstarstarstar 		operation and repair comments
by: Zebulon

the high speed of the motor is to improve the steering capacity of the robot. It is used to move faster from one area of the pool to another, the drag of the cable being higher with high speed.
about maintenance in the motor compartment box, there is no special gas inside. I have used silicon or ptfe gease to be sure not to damage the seal when closing the box.
I want to add also that I had the same problem as your mum, and I solved it by replacing the seals. With used seals, torque is increasing on the pump motor and the robot stops thinking that the beg is full....
Jul 17, 2012
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starstarstarstarstar 		reply to jim k
by: jason

I am still waiting on the electronics guy to finish up the controller. I think he has been pretty busy with work lately. Also, we have yet to see summer start here in the seattle area. My mom only started heating her pool a couple of weeks ago! I haven't forgotten and will post more info when I have it...
Jul 17, 2012
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starstarstarstarstar 		Upate on custom controller
by: Jim K

Wondering if you have completed your custom controller work and what the results are. Late post was from May, it is now mid July. I think we would ALL love to know.
Thanks for sharing
May 31, 2012
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starstarstarstarstar 		gasket or sealer
by: Anonymous

I have not heard the box is pressurized. If s, then I would expect to hear gas release when opened. I have Dolphin motors that I take apart to try and repair the ECB with little success. I have not damaged a gasket yet and I would only use a gasket sealer as a last resort to supplement a damaged gasket.
Liquid silicone is an excellent O-ring lubricant/sealer/conditioner
May 30, 2012
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starstarstarstarstar 		reply to dave
by: jason

I can't comment on what gas the box contained when I first opened it (oxygen or otherwise, though I suspect oxygen). I do know that there wasn't any silicone on the seal from the factory. The box is sealed with what appears to be a large "O" type ring. My friend that is designing the new controls says that there is a special type of coating (oil or ?) that is used on o-ring applications in the machining industry and it will not leak. We haven't reassembled the motor box yet. That should happen in the next few days as the power supply just came in the mail. I will report back when we have this thing up and running.
May 30, 2012
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starstarstarstarstar 		Motor box
by: Dave

From my understanding is that the motor box has a tight gas pressure that they seal with. So I took apart the motor box to check motors and they say that is a bad idea cause I have to send it back to get the gas pressure seal back and that I can't put silicone around it like you said. Is this true? Have you tested it and made sure that the silicone works and doesn't let water back into the motor box?
May 25, 2012
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starstarstarstarstar 		To anonymous/still need info
by: jason

Thanks for your reply. The one that I am trying to fix is the two speed model. I am pretty sure that the one I am fixing does not have the capability to steer. The motor directly drives one of the tracks and it is connected directly to the other track. I think what steers the dolphin is the power cord placing a slight drag on one side of the robot. This would cause it to arc slightly in it's path due to the slight pull of the cord.

The power supply has been ordered so hopefully someone will chime in that can help shed some light in regards to how this machine is supposed to operate. If not, then we will configure the electronics so that it will operate at only the fast drive speed. It will be set up so the suction pump will always be on. The drive track will run back and forth at infinitely adjustable increments. What most impresses me is that we can do all of this using only the +/- power leads that are already in place.

I will take pics and share the wiring schematics here. I think that in the end this repair will be comparatively similar costwise to having the unit repaired from the factory. We shall soon find out.

May 25, 2012
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starstarstarstarstar 		2 speeds
by: Anonymous

I have learned that older motors were single speed and newer models are two speed. Only Maytronics knows why.
I can speculate that the slower speed may be for turning or to ramp up to full speed.
May 23, 2012
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starstarstarstarstar 		Thank you Curt
by: jason

If it would be advantageous then I would like to include the slower speed option. If the slower speed is in fact used for the walls of the pool then I would need to include a sensor that can differentiate between a true vertical plane versus the almost vertical plane that exists in a pool with a 12 foot deep end. My mom's pool is an olympic size pool with a 12 foot deep end and has very steep walls coming out of the deep end of it. Thanks again for any information that you can provide.
May 22, 2012
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starstarstarstarstar 		I will work on the answer...
by: Curt

...to the question presented reference the two speeds.
If this works there are many owners that will be thankful for a fix to this common problem.
May 21, 2012
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starstarstarstarstar 		Request more info
by: jason

Thank you for replying to my post. I am aware that the motor runs forward and backward for the tracks that drive the unit. What I need to know is why the drive unit runs in two speeds. I have the motor box torn open and it will work for about one minute, then it shuts down. Though the little green light in the motor box keeps flashing as normal. After it shuts down, the only way to restart it is to shut off the power supply at the switch and wait five or ten seconds, then it will run again for about a minute. The controller that my friend has designed will run off of a new transformer installed in the power supply unit that senses overloads/faults and shuts down for a specified period of time, then restarts. The circuitboard in the motor box will be removed and he has an adjustable timer of sorts to put in it's place. I don't know the specifics as I don't do small electronics work. It is some kind of cnc (machine shop) type controller that will reverse the direction of the drive motor every X amount of seconds/minutes. It is adjustable from .1 seconds to 10 hours. He told me that he is pretty certain that he can make it adjustable at the power supply so we won't have to open the motor box again, save for motor failure. I will be more than happy to share what we learn here for the benefit of others, and that includes schematics as well.

The most important question I need an answer to is: Why does the drive motor have two speeds? Does the Dolphin Advantage have a sensor that tells it that it is climbing a wall, thus the slower speed? We are ordering the power supply in the next day or so and need to know how to set up the guts of the box.

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