Re: [PSUBS-MAILIST] re-wiring trolling motors?

["Herve Jaubert" <caribsub@coqui.net>]

Pat,
If you decided not to put a sacrificial anode somewhere on the end part of
the motor, the one where is the little fin, and if there is no electrical
continuity bewtween the axle and the steel shaft, then you would have to put
a connecting wire between the parts of the case , this technic is commonly
used by boat manufacturers they run a copper wire throughout the hull to
make sure everything is connected. The motor case comes  in 3 parts( MK or
MG) and is covered with a coating that probably does nt make good continuity
when they are assembled ( 1 on 3 are correctly connected), to ensure
continuity you have to attach a copper wire between the end part of the
motor and the shaft or directly on the anode. This wire could be outside the
body (uggly) or inside. you have then to open the body and attach the wire
inside the end of the motor case on a non moving metallic part. There is
another possibility : there is a small thread outside the case on the end
part of the motor, if you could find a sacrificial anode that could be
screwed in there you have your galvanic corrosion protection, unfortunately
the available space between the motor and the prop is very small, so the
anode should have the size of 1/4" screw and be replaced more often.
I was not successfull in finding such small anode, but it is the best way
since there is nothing more to do than screwing that little piece.
Even if you don t use the shaft or if the shaft is not in contact with salt
water, there is still galvanic corrosion of the engine with the motor axle
and some screws being in the water.
So if you keep your sub for long period of time in the ocean you should make
sure that the anode is electrically connected to the axle.
Before you make any work check your engine when you purchase it , may you
get lucky and there is good connection.
I don t know if the people of MK or MG are aware of this problem but they
are selling motors for saltwater that fail corrosion control.
It is true that part of the controller in the MG is in the lower unit. But
in my subs I don t mind, because I don t use it!
I don t beleive electronic variable speed is usefull for a sub, important
momentum , too heavy and too slow , I choosed to power my subs with 2
speeds, slow / fast, and in between I use bursts of thrust to achieve
variable speeds taking advantage of the momentum.
The advantages is you don t need the upper unit, slow speed is in 24 Volts,
fast speed is in 36 Volts.
you use only 2 of the wires and forget the controller and its wires inside
the lower unit.
Other adavantage is the cost, less expensive since you don t need the upper
unit, if you were interested I sale lower units MG 107 alone , forward and
reverse, 36 / 24 Volts, plus the stainless steel shaft, plus the sacrificial
anode to be mounted on the shaft and the prop kit for only $280, not
including shipping via UPS or check with your motor dealer, but this
solution is the most cost efficient.
I ll have to check tomorrow at the factory the exact dimensions of the lower
unit.
regards
Herve Jaubert

----- Original Message -----
From: Captain Nemo <vulcania@interpac.net>
To: <personal_submersibles@psubs.org>
Sent: Saturday, November 25, 2000 6:59 PM
Subject: Re: [PSUBS-MAILIST] re-wiring trolling motors?


>
> ----- Original Message -----
> From: "Herve Jaubert" <caribsub@coqui.net>
> To: <personal_submersibles@psubs.org>
> Sent: Saturday, November 25, 2000 7:54 PM
> Subject: Re: [PSUBS-MAILIST] re-wiring trolling motors?
>
>
> > It is actually simpler than to rewire the motor. (disassembling
required)
> > This procedure is important, otherwise under frequent use your motor
will
> be
> > galvanic corroded.
>
> Herve,
>
> What kind of rewiring are we talking about here.  Please describe.
>
> VBR,
>
> Pat
>
>
>