Re: [PSUBS-MAILIST] electric motor bearings

Thanks Vance,

I've gone with fixed vertical thrusters; so half the time they will be in reverse.

Maybe I'll buy another spare motor as you suggest.

The bearing issue seems to give weight to using rotating vertical thrusters & keeping them

running forward.

Regards Alan

----- Original Message -----

From: vbra676539@aol.com

To: personal_submersibles@psubs.org

Sent: Wednesday, May 04, 2011 1:47 PM

Subject: Re: [PSUBS-MAILIST] electric motor bearings

Alan,
For the price, I consider the Minn-Kotas to be disposable units. That said, many of the units are sold with reversing circuits,so the company must consider them viable for light duty, at least. Mine are replaceable in the water or out and carrying spares is a couple of hundred bucks--not much for peace of mind.
Vance

-----Original Message-----
From: alanjames@xtra.co.nz
To: personal_submersibles
Sent: Tue, May 3, 2011 4:43 pm
Subject: [PSUBS-MAILIST] electric motor bearings

Hi,

I asked the question a while back as to whether the minnkota motors had any

thrust bearings in reverse.

The answer seems to be "NO".

Here is a spare parts link that shows motors with only a circlip wich spins against washers

when the motor is in reverse.

http://www.northlandmarine.com/MinnkotaRiptide.html

I guess this would be an argument for oil compensating rather than air compensation or good shaft seals,

if you were intending to run the engine in reverse.

So if you had a motor that has an 80 lb thrust, it would be like spinning an 80 lb weight at X amount of revs

on a couple of dry washers.

I would appreciate any comment if I've got it wrong or it's not an issue.

Thanks, Alan.