Reason:

(1) The sensitivity of the sensor is wrong.

(2) The height of the vibration table is off-centre.

(3) Resonance between the vibration table and the shaker itself.

Solution:

(1) Check the sensitivity of the sensor.

(2) Check if the vibration table is in the middle when the power is turned on.

(3) <When it occurs during SINE test>
If it occurs at 10 Hz or lower, lock the body suspension.
However, use of the shaker with the body suspension locked will place a heavy load on the shaker and accelerate deterioration.

If the test continues beyond 10 Hz in a sweep test, press Pause when the frequency exceeds 10 Hz, unlock the body suspension with the shaker stopped, and resume the test.
Locking the body suspension during testing at frequencies above 10 Hz may cause the vibration to be transmitted significantly to the ground and in some cases may cause the shaker itself to move, resulting in a serious accident.

<If this occurs during RANDOM testing＞
Lock the body suspension.
However, there is a possibility that the shaker itself may start to move, so increase the vibration level while observing the situation.
Locking the body suspension will place a heavy load on the shaker and accelerate deterioration.