2 Engineering2.11 Motor connectionDS7 Soft starter 09/16 MN03901001Z-EN www.eaton.com 512.11.13 Repair and maintenance switchRepair and maintenance switches disconnect all the poles (all the phases) inthe connection cable to a motor. This prevents voltage from being appliedand the motor from being started by accident during repair and maintenancework.The DS7 soft starter has a two-phase circuit with semiconductor elements inthe power section, one phase is always connected through directly.Because of this, all the poles (all three phases) in two-phase controlled softstarters should always be disconnected from mains voltage in the stop state– with a contactor connected in series on the mains side, for example.If a control system does not provide this potential isolation, it is advisableto connect the motor through a repair or maintenance switch. DANGERIn both the disabled and stop states of the soft starter when themains voltage is present (terminals 1L1, 3L2, 5L3), there is alsoa dangerous voltage present at the output terminals (2T1, 4T2,6T3) and therefore also on the motor cables and connectionterminals of the motor (U, V, W)!Size 1 and 2 (4 - 32 A) Size 3 and 4 (41 – 200 A)Figure 33: Dangerous voltageM3 ~1L1 3L2 5L32T1 4T2 6T3M3 ~1L1 3L2 5L3 PEPE2T1 4T2 6T3
