Subject: TAKENAKA
Date: Tue, 1 Feb 2000 08:04:30 -0600
From: "Imafuku, Nobuhiro" <Nobuhiro.Imafuku@mts.com>
To: "Rood, Omar" <Omar.Rood@mts.com>, "Larson, Rod" <Rod.Larson@mts.com>
CC: "Reinhardt, Earl" <Earl.Reinhardt@mts.com>, "Shigemasa, Yukio"
     <Yukio.Shigemasa@mts.com>, "Katabami, Yoshihiro"
     <Yoshihiro.Katabami@mts.com>, "Otsuka, Yutaka" <Yutaka.Otsuka@mts.com>

Hello, OMAR & ROD san.

We did follows for both actuators but we still have oscillation
(unstable) problem when we apply $B!H(JLOW$B!I(J or $B!H(JHIGH$B!I(J pressure. Once we
apply $B!H(JHIGH$B!I(J pressure ignoring oscillation, we think system works
fine.
1.      We change main pressure check valve position from inlet line to
outlet line in all HSM.
2.      We check all accumulator charge pressure once more.
3.      We check pilot pressure when we apply $B!H(JLOW$B!I(J or $B!H(JHIGH$B!I(J
pressure, pressure gage always shows about 2900 psi.
4.      We change to set HSM low pressure step by step.
        1)      When we set $B!H(JLOW$B!I(J pressure at 500 psi, servo valve
spool moves so slow and if we change command signal by setpoint,
actuator suddenly moves.
        2)      When we set $B!H(JLOW$B!I(J pressure at 1000 psi, servo valve
spool moves smoothly and we thought this was good pressure for system
yesterday. But, when we apply pressure, actuator suddenly moves today
not only just after running HPS.
5.      We tune servo valve inner loop.
        1)      50 ton actuator : We think servo valve works OK.
        2)      100 to actuator : We have two pilot servo valves. We try
to tune only using one pilot servo valve. We think one servo valve works
OK but the other servo valve does not work OK because when we apply
$B!H(JDITHER$B!I(J, no sound hears. Off course, we put dummy connector. Then, we
tune inner loop using two pilot servo valve, and we think servo valve
works OK (we are little confused).
6.      We assume this problem is caused by parallel usage of HSM. We
need to adjust all HSM work correctly. Do you have any idea to adjust ?
TAKENAKA will have to start structure test from February 14th. So, we
will have to check We assume there is no checkout for TestStar IIs
software in Minneapolis, so that we need to check TestStar IIs software
works OK or not urgently. We will start to check tomorrow. TAKENAKA
people are so good to us and no one is upset in front of us. But, we
think TAKENAKA is extremely upset now. And, if same phenomena happen in
TestStar IIs software, TAKENAKA will have to wait to do test again.
Then, we have a big trouble. Also, if we can NOT succeed to convert load
cell file, we have another big trouble.

REGARDS     FUKU
