Secondary circuit control system special for data center chilled water pump

The invention provides a secondary circuit control system special for a data center chilled water pump. The secondary circuit control system comprises a power source, a fuse protector, a conversion switch, a manual stop button, a manual starting button and a contactor coil which are connected in sequence. The conversion switch comprises a manual position switch and an automatic position switch which are used for controlling a manual mode loop and an automatic mode loop respectively, the manual mode loop is controlled through the manual stop button, and the automatic mode loop is controlled through a DDC automatic mode circuit connected with the manual stop button in parallel. The contactor coil is connected with a first contactor normally-open contact and a second contactor normally-open contact in series, the first contactor normally-open contact is connected with the manual starting button in parallel, and the second contactor normally-open contact is arranged in the DDC automatic mode circuit. According to