Relay monitors phase sequence and failure (e.g. control of correct motor winding etc.).
HRN-56/120: 3 x 120 V HRN-56/208: 3 x 208 V HRN-56/240: 3 x 240 V HRN-56/400: 3 x 400 V HRN-56/480: 3 x 480 V HRN-56/575: 3 x 575 V