The LX4D4FD is a replacement contactor coil from the TeSys D range, designed to fit the corresponding contactor frame. It operates on a 110 V DC control circuit, with a voltage tolerance of 0.85 to 1.1 times the rated control voltage at temperatures up to 131 °F (55 °C).
The 110 V DC control voltage is the nominal coil rating — the contactor pulls in reliably at this level. The 0.85 to 1.1 Uc tolerance window means the coil holds in at as low as 93.5 V DC and must not see sustained voltage above 121 V DC at 55 °C. If your panel's DC supply droops under load, verify it stays above the dropout threshold for this coil.