Crouzet 84874320 hsv phase monitoring relay ip20 30 speed control crouzet 84874320 this hsv phase monitoring relay from crouzet has been designed for the control of overspeed underspeed operating rate and stopping equipped with a host of excellent features including measurement via discrete sensors 3 wire pnp or npn namur voltage 0 30v or volt free contact type works with either no or nc sensors crouzet 84874320 hsv phase monitoring relay