Rotary Magentic Motor

[dahai]

Hello All!

This is my first post on any ROV forum:

Currently designing a 'small' ROV with a maximum target operating depth of 100'.

To simplify wiring & overall waterproofing construction, I have been looking into designing a rotary magnetic motor for all thrusters.

Basic Breakdown:

- Series of 'wired' (electrified) magnets encased / sealed in plastic

- Drive-shaft set in place via plastic molding frame & low-friction rubber grommet

- Prop & Drive-Shaft surrounded by 'encased-magnet' housing

- Either Prop or Drive-Shaft contains magnets - ex. Prop blade-tips

- So long as 'wired' magnets are triggered in correct 'phase', Prop will rotate at appropriate speed(s)

How does this simplify construction?
- fewer electrical & mechanical parts exposed to water

I am in the process of learning to program Arduino microcontroller boards, and I see this to be a worthwhile 'workaround' to the maintenance and waterproofing measures required for thrusters.

Figure if I am already establishing input and output codes for motors, may as well input electrical current codes to sealed magnets vs. motor control codes PLUS waterproofing wiring paths.

Any Thoughts Are Welcome

Thanks

DaHai

[Mareike]

Is a bit of work coming up to you. I tried it as well but gave up before these motors were swallowing my budget. Beside that I have not the facilities to do it. My dad is working offshore and at present I am raping his office to do him proud :mrgreen: and expect him not coming by surprise home...
I changed to regular brushless motors into a hermetically sealed housing with using magnetic drive coupling discs, but sounds interesting to me and if you are going to build them some pics will be welcome here, I am looking forward to see them, as I hadn't the guts to make them because of the fear to end up with 6 useless motors, all with different power and empty wallet.

[howard1954]

DaHai,

We manufacture magnetic co-axial and disc couplings that have been used in many ROVs. Please visit our website:
http://www.magnetictech.com/prod_magcoup.htm

We have agents and distributors worldwide, including HUCO, SDP/SI, McMaster-Carr, TEA transmissions, to name but a few.
If we do not have an agent in your country, please contact us directly: sales@magentictech.com

:ugeek:
Howard Schwerdlin
Sales Manager

[Joe]

I actually was thinking along the very same lines for a micro-ROV design I've been working on. The design I landed on was three electromagnets consisting of small steel (painted) machine screws wound in magnet wire, and then four sections of steel rod pressed into the hub of the rotor. It's entirely dependent on attraction of the steel, so these motors would be very inefficient, but the design was for simplicity.

[Mareike]

Hi Howard,
I ordered 16ea of 50mm Disc Couplings and was more than surprised about the Power they have. The first Motor (Brushless 1800Kv) I tried had no slip at all even the air gap is 5mm. The Propeller driven by your couplings from magnetic technologies almost broke my dad's fingers as he tried to make the coupling slipping. NO chance at all he had..
Absolute fantastic solution to make the motor housing watertight.
Because of the power of the magnets allow a at least 20-25 cm shaft (anti magnetic) between coupling and brushless motors to avoid interference of the Motors and hold the shaft in position with 2 bearings otherwise the strong magnet will rip the motor shaft out of the housing like a rotten tooth. (Lesson learned
I just can say WOW, never expected that much magnetic power in such small diameter, fantastic product.
Thanks Howard for your backup before order you served me well. In case the 65mm propellers are too small I can easy take a 120mm size without making the couplings slipping.
Looking forward to shred some squids
Mareike

[parco]

Mareike, can you go into further detail on how you prevented the shaft from being ripped out of the dc motor?