Saturday, August 8, 2009

RE: [Electric Boats] 4kw "Arby" motor?

 

To those that want to use there installation in salt water. The use of lock-tight on the threads of your stainless bolts when installed in aluminum material will reduce galvanic corrosion. It is best to use plastic bushings in holes the bolts pass through and a fiber washer under the head.

A simple look at the mast of several ocean going sailboats will explain the reason this is so important.
 Fully enclosed motors lower corrosion problems with terminals and the magnetic core, but if it is not an option to keep terminals from being exposed there are coatings available at marine supply stores.  I suggest water tight enclosures for any terminals you must deal with.  Cooling the inside of any enclosure can be accomplished using pelter junctions        ( increasing cooling increases reliability of controllers).

Using marine wire is by far the best way to avoid faults caused by corrosion in your wiring. The difference in wire is the plating of the wire, keeping salt off of the copper is a real biggie.  There are many places on the web that help you understand proper wiring procedure for marine usage.

If your installation is inboard, then protecting your motor and drive train is more important than if you are converting an outboard for your drive. Inboard use may require stainless shafts and bearings in the motor.  Alternatively you might consider ceramic bearings. Believe it or not, if you can keep things dry in the boat then it is likely you won't have problems with your electric system for quite some time. My 83 catalina 30 was proof of that in I sold it with all the original switches and junction blocks that were installed at the factory. If your shaft box, or seal, leaks at all it will sling salt water over everything and bearings and shafts will suffer the most. There are shaft seals that will run without leaking but a standard stuffing box is adjusted to drip a little while being used  (All the electrical that went through the engine compartment, did however have to be minded to on a regular scedule to fix corrosion problems). For electric
installation it is probably better to use a "drip less" setup and avoid a multitude of problems including the slipping of your drive belt with water in the belt drive.

In conclusion; money spent on better seals will reduce the amount of money spent water proofing everything else.

Kevin
http://simplyrv.imnugget.com

For RV information

--- On Sat, 8/8/09, Myles Twete <matwete@comcast.net> wrote:

From: Myles Twete <matwete@comcast.net>
Subject: RE: [Electric Boats] 4kw "Arby" motor?
To: electricboats@yahoogroups.com
Date: Saturday, August 8, 2009, 8:11 AM

 

Arby-

Thanks for the tip/idea regarding using conformal coat.if I were to consider

that, I'd consult my motor expert first.

But with 6yrs or so now on my Etek brush motor, with nominally 20 excursions

per year, corrosion has not been an issue, period.

Refresh: my motor is bolted with stainless bolts to aluminum motor mount,

with aluminum fan shroud and fan directly connected to the motor with fan

just above the brush housing.

All of this is under the stock outboard motor cowl. The fan pulls air up

thru the motor, vacating brush dust and any other 'stuff' might get sucked

thru the motor. It's probably one of the cleanest motors out there and the

cooling provided allows my motor to efficiently deliver 6HP continuous at

36v.

As regards controller-related failures, I stand by my earlier assertion that

corrosion had nothing to do with 95% or more of the ones I've known about

that have failed.

In fact, I'm being conservative with this number as I frankly have never

heard of someone's controller failing due to corrosion.

I'm being specific here as regards to controllers because you were

specifically raising conern about the 'open header' of the Sevcon

controller, essentially asserting it is an inferior design because of this.

I totally agree that mitigating against the effects of corrosion is

important in any installation and all system elements and may be cause of

most system problems (I wouldn't call these failures necessarily- --however,

corrosion leading to high contact resistance that causes a battery post to

fail would be a failure).

So sure, corrosion is a major challenge.

But please don't imply that any significant number of controller or motor

failures are due to corrosion--- there's just no evidence of this.

Have you posted your Mark I/II/III/etc. controller/motor specs online yet

for us to review? Product that is available to the public for sale should

have reviewable specs if discussed on this forum.

-Myles Twete, moderator, Electric Boats

From: electricboats@ yahoogroups. com [mailto:electricboats@ yahoogroups. com]

On Behalf Of Arby Bernt

Sent: Friday, August 07, 2009 5:07 PM

To: electricboats@ yahoogroups. com

Subject: Re: [Electric Boats] 4kw "Arby" motor?

So Miles, you're saying if you run hard aground, it means your boat broke?

Allow me to re-phrase my observation:

Most of the problems encountered in carefully installed and tested systems

are related to electro-mechanical interfaces. Magnet corrosion and the

epoxy/plating interface certianly do not fall into this catagory. I'm glad

to hear your motor is still going strong. I would much rather hear success

stories than the problems I'm usually called upon to solve.

You might consider spraying some conformal coating in your motor if it

spends it's life over the water. Very flammable stuff until it dries, so

please be careful. I use plenty in every motor. Consider it preventative

maintenance. Battery terminal spray will help keep corrosion in check on the

battery interconnects and the controller. Messy, but effective.

Be Well,

Arby

On Aug 7, 2009, at 5:12 PM, "Myles Twete" <matwete@comcast. net

<mailto:matwete% 40comcast. net> > wrote:

Arbi offered: "95% of system failures are due to electro-mechanical

interfaces".

Maybe so, but that's not my experience.

And even IF so, 99% of those failures were likely due to operator error or

poor installation- --i.e. poor maintenance or design.

Yes, bad solder joints, bad crimps, unclean or corroded connections are

responsible for high resistance that can lead to poor performance or

failure.

But does that mean we stop using any of these techniques or only ever

connect electrical devices if within enclosures that meet arbitrary Federal

Regulations? No.

But let's get specific.

Speaking strictly of controller failures, as I've followed EV usage of them

since 1993, I'd estimate at least 95% of the failures that I have personally

experienced or read about were NOT due to electro-mechanical interface

issues at all.

Rather, the primary killers are:

. Non-existent pre-charge resistor circuit (sudden inrush into

controller kills bulk capacitor)

. Marginal or non-robust controller design (don't handle brief

overloads gracefully and outputs get fried)

. Insufficient thermal mounting of controller (controller overtemp)

. Incompatibility between controller and load or motor load profile

(eg. running continuously at controller peak rating)

. Blowing up controller by incorrect wiring on installation

I have been running now with a brush motor (ETEK), Curtis or Alltrax

controller, T-105 batteries and have had little or no corrosion issues (a

couple battery connections is all).

While I'm not operating in a salt-water environment, my boat has been

continuously moored on the Columbia since 1996 and operating as an electric

since about 2003. I haven't a clue about meeting any Federal Regulations as

regards enclosures-- -is this an insurance concern or what?

I'd gladly use a Sevcon.and sure, it'd need to be protected from water (as

with my Alltrax), but seriously Arby, unless you are giving up on your

brushless motor and simple 24v brushless controller and instead packaging

Sevcons with brush motors, why are you concerning yourself with a housing

that meets Federal regulations for a controller in your personal private

boat when you can mount your Sevcon in part of the cabin? I'd be very

concerned about trading off good thermal design for putting a controller in

a housing to ostensibly meet some regulation that you already meet by

locating the electronics behind a control panel. Again, contact resistance

issues are only responsible for failures in cases where poor maintenance or

installation are concerned. And that's a tiny minority of brush motor

controller failures. The Sevcon and Alltrax (and other) brush controllers

are excellent controllers and are somewhat resistant to the primary killers

I mentioned above unlike others that are easily killed by mistakes.

-Myles Twete, Portland, Or.

From: electricboats@ yahoogroups. com <mailto:electricboa ts%40yahoogroups .com>

[mailto:electricboats@ yahoogroups. com

<mailto:electricboa ts%40yahoogroups .com> ]

On Behalf Of Arby bernt

Sent: Thursday, August 06, 2009 5:23 PM

To: electricboats@ yahoogroups. com <mailto:electricboa ts%40yahoogroups .com>

Subject: Re: [Electric Boats] 4kw "Arby" motor?

Hi Cris,

I would like to test a motor using a 48v Sevcon controller. Brian has

suggested the same. I'll need to prepare a motor for an external controller,

and a housing for the Sevcon that meets Federal Regulations. Of particular

note is the 3/4" conductive sphere test...as well as the obvious corrosion

issues posed with the open header with its plated connectors. My experience

has been that at least 95% of all system failures are the result of

electro-mechanical interfaces. The plated spring bronze receptacles on the

Sevcon signal header and the contactor are fine for dry environments, and

will function fine for testing, but I would never consider them capable of

providing 10+ years of service-free reliability, even with an industrial

strength housing. There are a pair of Electric Wheel motors and controllers

on E-Bay. Have a look at them to see what happens when industrial enclosures

are used in a marine enviroment.

Arby

____________ _________ _________ __

From: Chris Witzgall <chris@witzgall. org <mailto:chris% 40witzgall. org>

<mailto:chris% 40witzgall. org> >

To: electricboats@ yahoogroups. com <mailto:electricboa ts%40yahoogroups .com>

<mailto:electricboa ts%40yahoogroups .com>

Sent: Thursday, August 6, 2009 10:33:44 PM

Subject: [Electric Boats] 4kw "Arby" motor?

I would think a 48v version, perhaps that can run on 24v as well, would be a

hit. Our boat, 10k lbs on paper, and more in real life, would not be

suitable for a 2kw motor, but might get along with a 4kw version.

Arby - if you are reading this - have you looked into the possibility of a

4kw version of your motor?

Chris

On 8/6/09 10:17 AM, "aweekdaysailor" <aweekdaysailor@ yahoo.com> wrote:

>

>

>

>

> We had a sail-in to Treasure Island last weekend which included 4

e-boaters on

> 3 sailboats - mine, Hans K and Kevin brought his Erickson 27 powered by

Arby's

> [http://www.advanced marineelectricpr opulsion. com/] motor. Tomasz and

his wife

> came along on my boat (he's got an e-boat down in Monterey) so I got to

make a

> couple of new friends to boot.

>

> It was a great day for sailing and we hit the tides well (all coming from

a

> different spot on the bay). We'll hopefully get some pictures up soon.

>

> We did have a "watt race" - my boat and the Erickson running parallel and

each

> calling off watt (amp actually) readings. This was all very un-scientific

but

> we did calibrate the ammeters and had independent observers at least.

>

> Downwind, the 100% watt draw advantage (for example I was at 2KW, Kevin at

> 1KW) was pretty close to true. Upwind (about 15kts) it narrowed a bit to

about

> 50-60% fewer watts advantage (i.e. I was at 2KW vs 1.5KW for Kevin)-

making

> sense with that boat being about 30% lighter and a freshly scrubbed hull.

> (Kevin I'm going from memory, so please correct me if I mis-state). We

were

> nowhere near hullspeed - maybe 4kts down and 2-3 back.

>

> I'm still nursing a set of bad batteries, comparing very different boats,

mine

> needs a scrub, props, etc -- so unfortunately I don't place much faith in

the

> numbers - this was intended for fun more than anything else, though I'm

sure

> this will trigger some debates (what's the expected difference in those

hulls,

> etc...)

>

> That said...Arby' s motor is a very sweet package - very clean, compact,

and

> very robustly assembled (so much so I'm afraid pictures taken of my setup

are

> going to end up as "before" pictures like those diet ads in the

tabloids...) .

> In particular, I think the lack of exposed wiring will be a huge advantage

in

> long-term reliability in saltwater installations.

>

> I think more testing is in order before declaring it SF Bay ready for a

boat

> as large as mine (30' 9800lb), but it seemed to me a good fit for the

Erickson

> and for the very large number of boats up to that size/vintage ready for

new

> motors. The 24volt package has obvious advantages as well, though I would

love

> to see 36V and 48V options.

>

> YMMV, Caveat Emptor and all that - but all in all I think it deserves

> consideration as a legitimate option in appropriate sized vessels and

sailing

> conditions. What "appropriate" means will involve further testing,

experience,

> testimonials, etc.

>

> -Keith

>

>

>

>

>>

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