# Study on Seismic Performance of a Mold Transformer through Shaking Table Tests
## 2 Experimental Program
### Test Setup and Measuring Instruments  
Figures 2 and 3 show the experimental setup and measuring instruments. The tri-axial tests were carried out using a shaking table, as shown in Figure 4. The main characteristics of the shaking table include: 4.0 m \(\times\) 4.0 m plan dimensions, six degrees of freedom (SDOF), maximum acceleration of 1.5, 1.5, and 1.0x \(g\) in the X, Y, and Z-directions, respectively, maximum pay load of 300 kN, and maximum overturning moment of 1200 kNm. The table is capable of reproducing earthquake input ground motions through a system of eight hydraulic actuators. Table 2 summarizes the specifications of the shake table. The mold transformer test specimen was anchored to a reinforced concrete slab via bed beam systems with eight M16 anchor bolts with diameters of 15.88 mm, according to the manufacturer's installation manual. The concrete slab was connected to the shaking table via M40 anchor bolts with diameters of 40 mm.  
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline
**Power Rating** & **Impedance** & **Voltage** & **No-Load** & **Standard** & **Dimensions** & & **Operating** \\
**(kVA)** & **(\(\pm\)10\%)** & **Regulation** (\%) & **Current** (\%) & **Efficiency** (\%) & **Length** & **Width** & **Height** & **Weight (kg)** \\ \hline
1000 & 4.99 & 1.3 & 2.5 & 99.4 & 1900 & 1030 & 2110 & 3800 \\ \hline \hline \end{tabular}
\end{table}
Table 1: Detailed specifications of the tested mold transformer.  
Figure 1: Configurations and details of test specimen. HV, high-voltage; LV, low-voltage: (**a**) Three-dimentional view; (**b**) Side view; (**c**) Plan view; (**d**) Photo of hybrid mold transformer.  
\begin{table}
\begin{tabular}{c c} \hline \hline
**Table Size (m x m)** & **4.0 x 4.0** \\ \hline Type & Fixed \\ Degrees of freedom & 6 \\ Full payload (kN) & 300 \\ Overturning moment (kNm) & 1200 \\ Acceleration at full payload (\(\times g\)) & 1.5 \\ \hline \(Y\)-axis & 1.5 \\ \(Z\)-axis & 1.0 \\ Maximum stroke (mm) & \\ \(X\)-axis & \(\pm\)300 \\ \(Y\)-axis & \(\pm\)200 \\ \(Z\)-axis & \(\pm\)150 \\ Operational frequency range (Hz) & 0.1–60 \\ \hline \hline \end{tabular}
\end{table}
Table 2: Detailed specifications of the shaking table used in this test.  
Figure 3: Photograph of test set-up and measurement instrumentation. TMDTs, tape measure type displacement transducers.  
Figure 2: Schematic of test set-up and measurement instrumentation. LVDTs, linear variable displacement transducers: RC = reinforced concrete.  
For measuring instruments, a total of five tri-axial accelerometers were used to record the acceleration response of the test specimen in three orthogonal directions during the tests. Four were mounted on the transformer at the top frame, left side, center zone, and the bed frame, while the fifth was mounted on top of the reinforced concrete (RC) slab (Figures 2 and 3). The accelerometer used in this test has a maximum capacity of \(\pm 200\times g\). To measure the mold transformer displacement, tape measure type displacement transducers (TMDTs) and static linear variable displacement transducers (LVDTs) were employed. As shown in Figures 2 and 3, a total of ten TMDTs were fixed on the steel frame out of the shaking table and positioned along the X, Y, and Z-directions at the top left and top right sides of the transformer; and two static LVDTs were positioned along the Z-direction at the bed beam. Furthermore, a total of six steel strain gauges were attached to the bottom beam and bed beam around the locations of linked bolts to monitor the variation of strain during shaking table tests, as shown in Figure 2.