Subject: TAKENAKA
Date: Sun, 6 Feb 2000 04:57:11 -0600
From: "Imafuku, Nobuhiro" <Nobuhiro.Imafuku@mts.com>
To: "Larson, Rod" <Rod.Larson@mts.com>
CC: "Rood, Omar" <Omar.Rood@mts.com>

Hello, ROD san.

System works fine under TestStar IIs software now. At first, we check 50
ton actuator.
1.      When we apply $B!H(JLOW $B!H(J and $B!H(JHIGH$B!I(J pressure at first time
(after tuning servo valve phase), actuator suddenly goes unstable
(oscillation). This phenomena is same as under 469DU software.
2.      We do NOT have any calibration file for TestStar IIs software,
so we calibrate LVDT first. After calibrating LVDT, actuator oscillation
problem is gone.
3.      We try to assume that :
        1)      TestStar IIs is used 10 kHz excitation with correct AC
phase (we did on-site). 469DU is used 2 kHz excitation with $B!H(JZERO$B!I(J AC
phase.
        2)      We change excitation from 2 kHz to 10 kHz and adjust AC
phase under 469DU software. When we apply $B!H(JLOW$B!I(J and $B!H(JHIGH$B!I(J pressure,
actuator does NOT go unstable (oscillation).
We are NOT sure excitation frequency effects this phenomena. But, it
seems actuator oscillation problem is temporally gone under 10 kHz
excitation with correct AC phase. This is hard to understand for us.
Please reply your comment. We will try 100 ton actuator tomorrow.

REGARDS     FUKU
