<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body dir="auto"><div></div><div>Brian,</div><div>I wouldn't read a lot in to that experiment as far as heating goes, as when</div><div>the motor is under load it will be drawing a lot more amps & develop a</div><div>lot more heat.</div><div>But people run the Minnkotas with air compensation & get away with it.</div><div>Alan</div><div><br></div><div><br>On 25/03/2020, at 2:09 PM, Brian Cox via Personal_Submersibles <<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>> wrote:<br><br></div><blockquote type="cite"><div><div style="font-family:Arial, sans-serif; font-size:10pt;"><font size="2" style=""><font face="Arial, sans-serif"> Alan, </font></font><div><font size="2" style=""><font face="Arial, sans-serif"> In my case my motor pod contains about 8 gallons of WD40 . I ran the motors the other day , all day long for about 10 hours straight . The temp outside was around 60 F so it sort of simulated our water temperature here. I was surprised to discover that the expansion of the oil was not as much as I thought it would be , it was about 1/2 gallon. It reached a point where it stopped expanding, so I guess it reached a point of equilibrium with respect to the temperature. One problem I have is in the summer the oil actually expands more than when the motor is running just sitting there heating up from the ambient temperature. I think in the summer I'm going to disconnect the hose and put it into a bucket when sitting. </font></font></div><div><font size="2" style=""><font face="Arial, sans-serif"><br></font></font></div><div><font size="2" style=""><font face="Arial, sans-serif">Brian</font></font></div><div><font size="2" style=""><font face="Arial, sans-serif"><br></font></font></div><div><font size="2" style=""><font face="Arial, sans-serif"> </font></font><br><br><span style="font-family: Arial, sans-serif; font-size: 10pt;">--- <a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a> wrote:</span><br><br><span style="font-family: Arial, sans-serif; font-size: 10pt;">From: Alan via Personal_Submersibles <<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>></span><br><span style="font-family: Arial, sans-serif; font-size: 10pt;">To: Personal Submersibles General Discussion <<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>></span><br><span style="font-family: Arial, sans-serif; font-size: 10pt;">Subject: Re: [PSUBS-MAILIST] motor oil compensator</span><br><span style="font-family: Arial, sans-serif; font-size: 10pt;">Date: Wed, 25 Mar 2020 13:25:53 +1300</span><br><br><div style="font-family: Arial, sans-serif; font-size: 10pt;"></div><div style="font-family: Arial, sans-serif; font-size: 10pt;">Brian,</div><div style="font-family: Arial, sans-serif; font-size: 10pt;">there is this military de-classified 1972 document on pressure compensating.</div><div style="font-family: Arial, sans-serif; font-size: 10pt;"><a href="https://apps.dtic.mil/dtic/tr/fulltext/u2/894795.pdf">https://apps.dtic.mil/dtic/tr/fulltext/u2/894795.pdf</a></div><div style="font-family: Arial, sans-serif; font-size: 10pt;">I printed it out & had it bound.</div><div style="font-family: Arial, sans-serif; font-size: 10pt;">I found that the rotation of the motor was throwing the oil out of the motor</div><div style="font-family: Arial, sans-serif; font-size: 10pt;">housing & up in to the compensating tube. If you dived there would be added</div><div style="font-family: Arial, sans-serif; font-size: 10pt;">pressure to keep the oil in the motor housing, but this wouldn't happen transiting</div><div style="font-family: Arial, sans-serif; font-size: 10pt;">on the surface. As the oil also keeps the Motor cool, there may be a danger of</div><div style="font-family: Arial, sans-serif; font-size: 10pt;">the motor overheating in this instance.</div><div style="font-family: Arial, sans-serif; font-size: 10pt;">As you will find in the linked manual, a minimum of 5psi over pressure is the norm.</div><div style="font-family: Arial, sans-serif; font-size: 10pt;">I am going to use the same system as Cliff, with the relieving regulator dialled</div><div style="font-family: Arial, sans-serif; font-size: 10pt;">up to 5psi to give an overpressure. However my system has oil in it so I get it's </div><div style="font-family: Arial, sans-serif; font-size: 10pt;">cooling advantages & eliminate large air volume changes.</div><div style="font-family: Arial, sans-serif; font-size: 10pt;">Alan</div><div style="font-family: Arial, sans-serif; font-size: 10pt;"><br>On 25/03/2020, at 11:19 AM, Brian Cox via Personal_Submersibles <<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>> wrote:<br><br></div><blockquote style="font-family: Arial, sans-serif; font-size: 10pt;"><div><div style="font-family:Arial, sans-serif; font-size:10pt;"><font size="2">Seawater gets compressed up the hose, so never goes above the highest point of the hose. When oil heats up it spills into trap and cannot escape to the sea. </font><div><font size="2"><br></font></div><div><font size="2">Brian</font></div><div><font size="2"><br></font><br><span style="font-size: 10pt;">--- <a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a> wrote:</span><br><br><span style="font-size: 10pt;">From: Øystein Skarholm via Personal_Submersibles <<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>></span><br><span style="font-size: 10pt;">To: Personal Submersibles General Discussion <<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>></span><br><span style="font-size: 10pt;">Subject: Re: [PSUBS-MAILIST] motor oil compensator</span><br><span style="font-size: 10pt;">Date: Tue, 24 Mar 2020 22:21:15 +0100</span><br><br><div dir="ltr" style="font-size: 10pt;">You should avoid contact between the seawater and the oil. The oil will contaminate quickly and it will no longer be dielectric. <div>Just the hose from the motor to the tee is enough to compensate. You do not have to have a large volume of oil. Fill the hose with oil and cap it off, done. or make a neat yet more sophisticated solution. </div><div>Make the end lid of the motor as a flange assembly and instead of a lid, use a rubber diaphragm. This will then act as a compensator. You can even install a light spring pushing down on the diaphragm if you want a slight internal overpressure. </div><div><div><image.png><br></div></div></div><br><div style="font-size: 10pt;"><div dir="ltr">tir. 24. mar. 2020 kl. 21:28 skrev Brian Cox via Personal_Submersibles <<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>>:<br></div><blockquote style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div style="font-family:Arial,sans-serif;font-size:10pt"><font size="2">Here is a drawing for my oil compensator</font><div><font size="2"><br></font></div><div><font size="2"><br></font></div></div>_______________________________________________<br>
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</blockquote></div><br><div style="font-size: 10pt;"><br></div><span style="font-size: 10pt;">-- </span><br><div dir="ltr" style="font-size: 10pt;"><div dir="ltr"><div>Vennlig hilsen<br>Øystein Skarholm</div><div>91369599</div></div></div><span style="font-size: 10pt;">
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