The Model 550-X Vibration Switch provides low cost, reliable vibration protection for rotating machinery operating within the range of 120-60,000 rpm. The switch's vibration sensor, mounted perpendicular to the unit's base, responds to the velocity (in/sec) signal and effects automatic shut-down or alarm when pre-set limits are exceeded. The unit may be mounted with the sensitive axis in any plane (horizontal, vertical or axial), even in an inverted position. Two limit set points are provided. One is set for the maximum allowable vibration (in/sec), while the other is set for a percentage of that setting, tripping the alarm relay when that percentage is reached. A built-in, adjustable time delay prevents triggering due to transient vibrations. The switch can be wired for latch and remote reset or for automatic reset when vibration falls below set point. The unit has a 4-20 mA output that may be used with a panel meter or data logger, permitting analysis of vibration trends. Once the switch has been installed and the limits set, it requires no attention. The Model 550-X Vibration Switch is enclosed in an explosion proof housing suitable for Class I, Division 1, Groups C, D and Class II, Division 1, Groups E, F, G.