[PSUBS-MAILIST] Oil Compensator

[Jon Wallace via Personal_Submersibles]

Hi Sean,

I haven't had mine apart yet but I have to assume both seals (cup type) 
are oriented toward water.  Is there really a need for two seals for our 
purposes?  I wonder if just removing the outer one would take care of 
the inter-seal cavity.  Exploded parts diagram at 
https://cdn.shopify.com/s/files/1/0191/7628/files/2013-N-Minn-Kota-riptide-motors-rttransom-Riptide-101t.pdf?6255360441529777455



On 4/5/2017 3:08 PM, Sean T. Stevenson via Personal_Submersibles wrote:
>
> The best practice may not be easily achievable with a Minn-Kota 
> without extensive modification. That said, I would orient an inner 
> seal with lip inwards, and an outer seal with lip outwards. Pressure 
> compensate the motor cavity with oil at a bias pressure above ambient, 
> and separately pressure compensate the inter-seal cavity with oil at 
> exactly ambient pressure. This way, you are either changing pressure 
> or changing fluid across any single seal, but not both simultaneously. 
> Minor leakage across either seal in this implementation is 
> inconsequential. Both compensation mechanisms should have some reserve 
> volume to account for thermal expansion of the oil.
>
> Sean
>
>