Brushless winch

[awallin]

Alberto Spada (ITA) just wrote to tell me about his new website:
http://www.aa-parts.com/

The brushless technology certainly looks interesting!

I remember Rob Guyatt saying something about brushless already at the 2003 Worlds. The idea being to use the hall-sensor signals (which are required for commutation) as an encoder also. Since the hall-sensor sits on the motor shaft, and the motor rotates many many turns for each rotation of the drum, this would potentially be a very accurate way of measuring & controlling the winch drum position.

It would be interesting to measure the actual performance of RMG and Alberto's winches against e.g. the latest arm-winches from HiTec... (or has someone already done this? links?)

Anders

[Peter Allen]

Anders,what is your opinion of the circuit board being exposed,in one way it will be easy to change wires or spray it for self maintanence,but in most cases 90% of IOM's leak small or great amounts of water very few are totally dry.Peter

[Gyula]

On mainboom they say it is protected

Toni and I respond to all blog readers on the insulation board electronics.
The pictures you see on the web have been made to highlight the electronic, without the protection of epoxy insulation that incorporates all of the shares in a semitransparent film and anti-water. The same resin is used in applications "mission critical" in the military and civil when you need to have a high degree of insulation from moisture (eg on the electronic parts of construction equipment, trucks, armored vehicles, etc.).

Greetings to all,
Alberto Sword

[Peter Allen]

Thank you for clearing that up.Now as Anders has said we need one to be tested against the other winches on the market.I only have experience with RMG and have never even sailed a boat with an arm winch,as i tend to travel to regattas i always think in my mind the Hi Tec arm to be too easy to burn out get snags etc meaning your travel money is wasted so i always play it safe experiments i prefer to do in my own backyard.But nice to see new products,it takes alot of guts to go into this type of buisness as R/C sailboat racing is not the biggest sport in the world so you have to give them credit for taking the challange.

[Peter Allen]

Another question gentlemen 6,1 n-min. I cannot relate to this speed spec,what is the drum size and what is the comparable real time speed to lets say a RMG 280EF on a 32mm drum???

[Dave Alston]

I am very happy to see a viable alternative to the RMG winch on the market and I wish them all success. I am fortunate to work where I do and do have considderable electronic expertise in the other room and so I have adapted an old dead RMG to use a brushless motor and a PIC controller. Mine is no were near as nice as the unit on offer.

My circuit board is not in a case either and has run for nearly a year now in salt water and fresh water sailing. BUT it is marineised - the board heavily coated with resin. This I believe to be far better than putting it in a box since the box will sweat on the inside and this is why the old RMG unit died in the first place.

The brushless motor is from an old model aeroplane and has run faultlessly.

It is to be regretted that the price is so high but that is life. I would guess that sales volumes would be low until the AUS dollar strengthens of the EURO weakens. ( Ye Ye I have heard it before – development cost – tooling cost ….) But there are more than enough armchair sailors that will replace their existing winches just to have the newest gadget to show off at the pond.


ARM WINCHES…
I know some have no problem with them but as for me least said the better. I destroyed 3 over a 4-month period…( a very expensive experiment indeed) They are simply not powerful enough for the job and do not provide enough torque and they eat your battery.

Do not be fooled by the figures publish by HITECH or any servo specification for that matter. These are not the continuously rated torque, it is the stalled touque and the servo will die after when stalled for any time.

After you have fitted an 80mm long arm and doubling pulley you have an effective moment arm of 160 mm – So at best with 30 kg.cm you have at best 1.8 kg pull power

That is less than 50% of the pulling power of Graupner ECHO.

I put a discussion on MYA Forum in January about this very thing. Regrettably I did not get any sensible responses ( excluding 1 ) there so I returned to RMG.

ACCURACY –
Well I guess if you are an armchair sailor it is important to you but in reality it is not. You position the sail by eye at a distance of between 20 to 100 metres so who cares.

SPEED –
AA Parts specify 6.1 revolutions per minute

RMG specify 6.1 revolutions per second – ( I think that is a typo and should read 6.1 revolution per minute )

So they are both the same speed. The speed is not all that critical as far as I am concerned just as long as it keeps up with you unlike the old HITECH drum winch that you had to sheet 15 seconds before you needed it.

[Peter Allen]

An RMG is repedtively accurate in it's trim position i like that if i want to crack i prefer to do it on the joystick and not guess where i am,when i'm in i know where i am lol.
Speed you are not clear by any means on this equasion,feel free to call me RABBIT.

[Peter Allen]

I think the RMG spec is correct at 6.1 revolutions per sec at least the EF model.Per minute would be slower than the Hi tec drum.

[Alberto Spada]

Good morning to all.
They are Alberto Spada, owner of AA-Parts and builder of the new winch.
I would like to address some inaccuracies appeared on the forum, so as to give correct information.

SPEED
Both AA-Parts winch than that of RMG have the speed expressed in revolutions per second (if somewhere in the documentation you found revolutions per minute, let me know: it is a mistake, many thanks)

ELECTRONIC PROTECTION
As quoted by Gyula, and posted on the Italian blog Mainboom, the pictures you see on the web have been made to highlight the electronic, without the protection of epoxy insulation that incorporates all of the shares in a semitransparent film and anti-water. The same resin is used in applications "mission critical" in the military and civil when you need to have a high degree of insulation from moisture (eg on the electronic parts of construction equipment, trucks, armored vehicles, etc.).

POWER
To help those who need lots of power, we are developing a new winch brushless (will be ready in July). With the new brushless motor power not think it will be a problem.

In any case, for any information or technical data, are at the disposal of all the skippers.

Fair winds with AA-Parts!
Alberto Spada

[Rob Guyatt]

Hi Alberto,
Welcome to the winch game. Best of luck to you. Can I ask a question about the epoxy you are using on your electronics? Is it easy to replace leads? Over 90% of all winches returned to me for repair require replacement of the receiver lead and / or power supply leads. So as long as it is not a chore to replace the leads it sounds like a great idea to use that type of protection. If so I might try it myself

Cheers

[Nathaniel Deverell]

thinking of taking the circut board of an rmg and making a carbon and aluminium winch for myself. Dont have the time to sell mod kits.

[Rob Guyatt]

Thought I might reply to a few comments I have seen in this thread and elsewhere. First off, my circuits are dipped in circuit board lacquer so it's not as if they are just protected by the enclosure only. As mentioned previously the vast majority of repairs I do are for replacement of external wiring. That is power leads and receiver lead. The lacquer does a good job protecting the sensitive components on the board like the microcontroller etc. and it's easy to replace leads. Only very old winches (> 10 yrs) or winches that have been drowned have corrosion to any circuit components.

I recently had a call from a friend who overheard a discussion by a few disgruntled RMG users. Their complaints were of the unreliability of the RMG product. Their names are very familiar to me. Once or twice a year I receive these guys winches for replacement of the leads. The leads fail due to water getting to the connector ends of these leads. If these people were using any other winch product they would have the same problems. These guys must also go through a few receivers as well since for water to get to the receiver lead it is obviously in the receiver.

Because of the fact that most repairs (>90%) involve replacement of leads, I will not be using any circuit board protection that makes it difficult or impossible to replace wiring. I'll be sticking with lacquered circuit enclosed in small plastic box. I'm always open to suggestions of better ways to do things but after about 25 years of employing this method, experience suggests it's still the way to go for now.

I have had a few people ask when I am going to reduce the price of my products to compete with Alberto. The answer is never. We have not increased our prices since about 2004. Wages have gone up such that I am now for my 60 to 80 hr week earning about the same as my son in law who works 40 hrs a week driving a fork lift in a warehouse. I am continuing with this because of the lifestyle and fun of doing what I love. If competition means I quit this and get a real job then so be it. If I went back to my previous full time job that I left in 1999 I would be earning 50% more than I am now for half the hours per week.

Brushless motors. I evaluated these along with magnetic feedback encoders several years ago. There are a handful of brushless servos on the market now and also a few servos with magnetic feedback encoders. But still the majority are using brushed motors and potentiometers for feedback. The magnetic encoders are a good option for single turn servos but are problematic for multi turn servos such as drum winches. The problem with brushless motors is still cost. I suspect that brushless motors may well become viable eventually. But not until their cost of use becomes very close to cost of brushed motors will I bother with them. The benefits of improved performance ultimately means only a saving of weight. Now in most IOM yachts this only means less winch weight (perhaps 10 to 20 grams) that must go into corrector weights. The argument that there aren't brushes to wear out is irrelevant because I have never replaced a 380 motor due to worn out brushes although commutator can be a problem if no maintenance is done and 280 motors take about ten years or more on average to go through a set of brushes but the commutator handles lack of mainenance better than the 380.

[Jeff Kay]

Hi Rob
Hope you stick with the winch making ! I've currently got 6 RMG winches of various ages (New up to 10 years old) and have never had any problems whatsoever.
In Euro terms the prices have increased but that has been due to the AUD/Euro fx rate which is beyond your control.
My boats over the years (Ts2/SC4/Disco/Obsession) didn't leak and I think that's the key.
Jeff