<html xmlns="http://www.w3.org/1999/xhtml" xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office"><head><!--[if gte mso 9]><xml><o:OfficeDocumentSettings><o:AllowPNG/><o:PixelsPerInch>96</o:PixelsPerInch></o:OfficeDocumentSettings></xml><![endif]--></head><body><div style="color:#000; background-color:#fff; font-family:Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:16px"><div><span></span></div><div class="qtdSeparateBR" id="yui_3_16_0_ym19_1_1491419564878_2626">Jon,</div><div class="qtdSeparateBR" id="yui_3_16_0_ym19_1_1491419564878_3309">Cliff has been doing a lot of work on Minn kota modifications & has the hands</div><div class="qtdSeparateBR" id="yui_3_16_0_ym19_1_1491419564878_3310" dir="ltr">on experience. If he's not tuning in it would be worth contacting him privately.</div><div class="qtdSeparateBR" id="yui_3_16_0_ym19_1_1491419564878_2892" dir="ltr">The Minn-kota seal set up is not ideal, with the gap between the two seals</div><div class="qtdSeparateBR" id="yui_3_16_0_ym19_1_1491419564878_2719" dir="ltr">meaning one or the other seals will fail when their pressure rating is exceeded.</div><div class="qtdSeparateBR" id="yui_3_16_0_ym19_1_1491419564878_2720" dir="ltr">The outer seal seems to serve a double purpose, being the first line of defense</div><div class="qtdSeparateBR" id="yui_3_16_0_ym19_1_1491419564878_2815" dir="ltr">against water ingress & also a sacrificial seal that will see all the abrasive muck stirred up by the prop.</div><div class="qtdSeparateBR" id="yui_3_16_0_ym19_1_1491419564878_2774" dir="ltr">Noticed in this kit that the outer seal has a shield to protect it.</div><div class="qtdSeparateBR" id="yui_3_16_0_ym19_1_1491419564878_2775" dir="ltr"><img id="yui_3_16_0_ym19_1_1491419564878_2777" src="http://cdn3.bigcommerce.com/s-9zqwsza/products/284334/images/633/880-006__65028.1446824316.1280.1280.png?c=2" data-id="27fba912-f492-82f7-b4e7-4937b3395b2d"></div><div class="qtdSeparateBR" id="yui_3_16_0_ym19_1_1491419564878_2850" dir="ltr">Historically in deep diving set ups they have had dual seals, but with either ambient pressure between them,</div><div class="qtdSeparateBR" id="yui_3_16_0_ym19_1_1491419564878_2867" dir="ltr">or a cascaded pressure system, and normally mechanical seals. The outer seal was regarded as sacrificial.</div><div class="qtdSeparateBR" id="yui_3_16_0_ym19_1_1491419564878_2911" dir="ltr"> Maybe you could pack between the seals with grease to reduce the air gap. </div><div class="qtdSeparateBR" id="yui_3_16_0_ym19_1_1491419564878_2950" dir="ltr">I am not sure whether you could simply reverse the inner seal or not as they need a shoulder that the pressure</div><div class="qtdSeparateBR" id="yui_3_16_0_ym19_1_1491419564878_2949" dir="ltr">will push them up against.</div><div class="qtdSeparateBR" id="yui_3_16_0_ym19_1_1491419564878_3128" dir="ltr">Cliff is using a small relieving air regulator to compensate his motors. The regulator is fed air from your tanks</div><div class="qtdSeparateBR" id="yui_3_16_0_ym19_1_1491419564878_3107" dir="ltr">& is set at an overpressure of about 4psi. The regulator is orientated upside down as the relieving air feeds</div><div class="qtdSeparateBR" id="yui_3_16_0_ym19_1_1491419564878_3129" dir="ltr">out through the handle portion & the orientation will stop water entering when this valve opens.</div><div class="qtdSeparateBR" id="yui_3_16_0_ym19_1_1491419564878_3142" dir="ltr">This system was suggested by Hugh, & Cliff is trialing it. It has the advantage that you could either air or oil</div><div class="qtdSeparateBR" id="yui_3_16_0_ym19_1_1491419564878_3130" dir="ltr">compensate. If your motor ran out of oil it would just be replaced with air above ambient pressure.</div><div class="qtdSeparateBR" id="yui_3_16_0_ym19_1_1491419564878_3131" dir="ltr">I am not sure at what pressure the relieving valve opens.</div><div class="qtdSeparateBR" id="yui_3_16_0_ym19_1_1491419564878_3233" dir="ltr"> There is this very good Psub resource from an expert in modifying Minn kotas for underwater use.</div><div class="qtdSeparateBR" id="yui_3_16_0_ym19_1_1491419564878_3259" dir="ltr"><a class="enhancr2_63884c4a-388d-f203-2e50-4db0f7849991" id="yui_3_16_0_ym19_1_1491419564878_3263" href="http://www.psubs.org/designguide/wmkmotor.html">Personal Submersible: White Paper: Minn Kota Motor Notes</a></div><div class="qtdSeparateBR" id="yui_3_16_0_ym19_1_1491419564878_3286" dir="ltr">Cheers Alan</div><div id="yui_3_16_0_ym19_1_1491419564878_3268"><br></div><div class="yahoo-link-enhancr-card yahoo-link-enhancr-not-allow-cover ymail-preserve-class ymail-preserve-style" id="enhancr2_63884c4a-388d-f203-2e50-4db0f7849991" style='font-family: "Helvetica Neue", Helvetica, Arial, sans-serif; max-width: 400px;' dir="ltr" contenteditable="false" data-size="medium" data-type="yenhancr" data-embed-url="" data-category="article" data-url="http://www.psubs.org/designguide/wmkmotor.html"> <a class="yahoo-enhancr-cardlink" id="yui_3_16_0_ym19_1_1491419564878_3283" style="color: rgb(0, 0, 0) !important; text-decoration: none !important;" href="http://www.psubs.org/designguide/wmkmotor.html" target="_blank" rel="noreferrer"> <table class="card-wrapper" id="yui_3_16_0_ym19_1_1491419564878_3282" style="max-width: 400px;" border="0" cellspacing="0" cellpadding="0"> <tbody id="yui_3_16_0_ym19_1_1491419564878_3281"><tr id="yui_3_16_0_ym19_1_1491419564878_3280"> <td width="400" id="yui_3_16_0_ym19_1_1491419564878_3279"> <table width="100%" class="card-info" id="yui_3_16_0_ym19_1_1491419564878_3278" style="background: rgb(255, 255, 255); border-width: 1px 1px 3px; border-style: solid; border-color: rgb(224, 228, 233) rgb(224, 228, 233) rgb(0, 0, 0); border-image: none; max-width: 400px;" border="0" cellspacing="0" cellpadding="0"> <tbody id="yui_3_16_0_ym19_1_1491419564878_3277"><tr id="yui_3_16_0_ym19_1_1491419564878_3276"> <td style="padding: 16px 0px 16px 12px; vertical-align: top;"> </td> <td id="yui_3_16_0_ym19_1_1491419564878_3275" style="padding: 16px 12px; width: 99%; vertical-align: middle;"> <h2 class="card-title" style='margin: 0px 0px 4px; font-family: "Helvetica Neue", Helvetica, Arial, sans-serif; font-size: 16px;'>Personal Submersible: White Paper: Minn Kota Motor Notes</h2> <div class="card-description" style="color: rgb(153, 153, 153); line-height: 15px; font-size: 11px;"></div> </td> <td class="card-share-container"></td> </tr> </tbody></table> </td> </tr> </tbody></table> </a></div><div id="yui_3_16_0_ym19_1_1491419564878_3346"><br></div><div class="qtdSeparateBR" id="yui_3_16_0_ym19_1_1491419564878_3132" dir="ltr"><br></div><div class="qtdSeparateBR" id="yui_3_16_0_ym19_1_1491419564878_2987" dir="ltr"> </div><div class="qtdSeparateBR" id="yui_3_16_0_ym19_1_1491419564878_2912" dir="ltr"><br></div><div class="qtdSeparateBR" id="yui_3_16_0_ym19_1_1491419564878_2868" dir="ltr"><br><br></div><div class="yahoo_quoted" id="yui_3_16_0_ym19_1_1491419564878_2547" style="display: block;"> <div id="yui_3_16_0_ym19_1_1491419564878_2546" style="font-family: Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 16px;"> <div id="yui_3_16_0_ym19_1_1491419564878_2545" style="font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 16px;"> <div id="yui_3_16_0_ym19_1_1491419564878_2544" dir="ltr"> <font id="yui_3_16_0_ym19_1_1491419564878_2543" face="Arial" size="2"> <hr size="1" id="yui_3_16_0_ym19_1_1491419564878_2624"> <b><span style="font-weight: bold;">From:</span></b> Sean T. Stevenson via Personal_Submersibles <personal_submersibles@psubs.org><br> <b><span style="font-weight: bold;">To:</span></b> Personal Submersibles General Discussion <personal_submersibles@psubs.org> <br> <b><span style="font-weight: bold;">Sent:</span></b> Thursday, April 6, 2017 7:10 AM<br> <b><span style="font-weight: bold;">Subject:</span></b> Re: [PSUBS-MAILIST] Oil Compensator<br> </font> </div> <div class="y_msg_container" id="yui_3_16_0_ym19_1_1491419564878_2622"><br><div id="yiv8500628609"><div id="yui_3_16_0_ym19_1_1491419564878_2621"><div id="yui_3_16_0_ym19_1_1491419564878_2623" dir="ltr">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.</div>
<div dir="ltr">Sean<br>
</div>
<br><br><div class="yiv8500628609gmail_quote" id="yui_3_16_0_ym19_1_1491419564878_2620">On April 5, 2017 11:49:51 AM MDT, Jon Wallace via Personal_Submersibles <personal_submersibles@psubs.org> wrote:<blockquote class="yiv8500628609gmail_quote" id="yui_3_16_0_ym19_1_1491419564878_2619" style="margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex; border-left-color: rgb(204, 204, 204); border-left-width: 1px; border-left-style: solid;">
<pre class="yiv8500628609k9mail" id="yui_3_16_0_ym19_1_1491419564878_2618"><br>I haven't designed mine yet Rick which is why I'm asking the question. <br>I guess the first question is whether one of the seals can be reversed <br>to prevent oil from escaping around the motor shaft. I think I recall <br>Hank mentioning something about this but I don't know if it was on a <br>minn-kota. I'm also not sure if oil egress is due to heat/pressure <br>build up or because the motor is designed to keep water out, not oil in.<br><br>We've got different people saying different things so I'm hoping we can <br>come up with a "best practice" solution and document it in a white paper.<br><br>Jon<br><br><br>On 4/5/2017 1:23 PM, Rick Patton via Personal_Submersibles wrote:<br><blockquote class="yiv8500628609gmail_quote" style="margin: 0pt 0pt 1ex 0.8ex; padding-left: 1ex; border-left-color: rgb(114, 159, 207); border-left-width: 1px; border-left-style: solid;"> Jon<br><br> What type of system did you use for the oil to go to when it gets hot?<br><br> Rick<br></blockquote>
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