Siemens 3RT29261MR00 Motor Starter Control. Siemens SIRIUS Surge Suppressor 24 VDC 24 VDC Coil For Use With: SZ S0 Motor Contactor 11.5 mm L x 18.6 mm W x 30.2 mm H Dimensions. Additional Description: SIEM-3RT29261MR00 SURGE SUPPRESR DIODE LED S0 24VDC. Catalog Description: Surge suppressor diode combination with led DC 24 V for motor contactors sz s0.