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Oil Pressure - psid??

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Old 9th Jul 2018, 06:19
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Oil Pressure - psid??

I always thought (be nice now...) engine oil pressure (always been turbine) was presented / given in straight psi - but doing some related research, I find 'limits' shown in psid.

Am I just confused (or stupid - or both....) - what gives?

Thanks much.
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Old 9th Jul 2018, 12:24
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....differential
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Old 9th Jul 2018, 14:23
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Yes, but differentialfrom what? I get the psid (differential) when referring to say, cabin pressure, but oil pressure?

I don't ever remember (or maybe just forgot...) the 'd' part when referring to oil pressure.

Gracias.

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Old 9th Jul 2018, 14:50
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Google is your friend.
look for
coulton.com/beginners_guide_to_differential_pressure_transmitters.html

seer
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Old 9th Jul 2018, 16:56
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Originally Posted by slowto280 View Post
...but doing some related research, I find 'limits' shown in psid.
In what context did you see this "limit" mentioned ? Were you supposed to read a number somewhere on a gauge or was it just a psid at which something takes place, e.g., a bypass valve opens or a cockpit warning is sent for a clogged engine oil filter ? This would be a number one doesn't need to know and you'd have to get a MTC manual to find it.
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Old 10th Jul 2018, 18:56
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the diff pressure is normally the difference between the supplied pump pressure and the vent pressure of the bearing chambers
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Old 15th Jul 2018, 04:26
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Looking at Type Certificate Data Sheet on GE90 engine (long story....) - Oil Pressure Limit(s) shows - Low Pressure (differential): 69 kPa (10.0 psid).

As I said, seems I have never seen oil pressure limits shown in psid - only psi.

Have never seen oil pressure indicators labeled psid always just psi.

Maybe 'new' EICAS indication is different.......

Thanks.
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