|
|
|
|
|||||
|
||||||
From: Phil Keys (no email)
Date: Sat Mar 03 2007 - 13:29:54 EST
Hello all you autopilot experts.
Kathy K has a problem with air getting into the hydraulic steering
when the autopilot has to work hard. It then takes many turns of the
wheel to work out the air. The steering is OK when the autopilot
isn't used. The Wagner T-2 steering ram has been rebuilt so now I
suspect the old autopilot belt driven pump (40 years old?). I am
trying to determine the correct size replacement pump. The pump
motor is controlled by a Cetrek autopilot computer.
I have read that the time for hard over in one direction to hard over
in the other direction should be 10-15 seconds. The ram's
displacement is 9.9 cu. in. which translates to a pump rate of 40 to
60 cu. in./minute. There are a number of Raymarine Type 1 pumpsets
on eBay which have a flow rate of 67 cu. in./min. This gives a hard
over to hard over time of 9 seconds which seems a bit quick.
So the question is, can I use a valve on the pump output to either
throttle the flow rate or bypass some of it? Or should I try to
adjust the Cetrek controller to compensate for a faster flow
rate? Or should I look for a slower pump?
I think the autopilot computer drives the pump motor at a constant
rate rather than at a variable rate. When the autopilot is working
the pump is constantly turning back and forth in short bursts.
I could keep the old 12 vdc motor, hydraulic manifold with the
pressure relief valves and external lock valve and just replace the
built driven hydraulic pump but I think a modern pumpset combines all
of those into one unit. I know the displacement of the old pump but
I don't know the motor's rpm. It looks pretty slow.
Phil Keys
Kathy K Willard 36, hull #34
Port Hadlock, WA 98339
_______________________________________________
http://lists.samurai.com/mailman/listinfo/trawlers-and-trawlering
To unsubscribe send email to
with the word
UNSUBSCRIBE and nothing else in the subject or body of the message.
Trawlers & Trawlering and T&T are trademarks of Water World
Productions. Unauthorized use is prohibited.
|