STAR-DELTA RELAYS M STAR-DELTA BOX FAN 3 K3 K1 K2 N L1 L2 L3 35 36 37 38 39 40 STAR-DELTA BOX 45 K3 5 K1 K2 1 2 3 N L1 L2 L3

STAR-DELTA MODE OPERATION 5 42 From #6 of control box; conditions to be energised: 1) auxiliary circuit ‘ON’ 2) No lock out of control box 3) min air P.switch at stand-by position at beginning 4) max air P.switch closed 5) limit controls closed 6) fuel selected gas side: 7) leakage control OK 8) min gas P.switch closed K1 K1 K2 K1 = = 45 K4 K3 K2 K4 K1 K2 K3 N

STAR-DELTA MODE OPERATION 5 42 K1 K1 K2 K1 = = 45 K4 K3 K2 K4 K1 K2 K3 N

STAR-DELTA MODE OPERATION 5 42 K1 K1 K2 K1 = = 45 K4 K3 K2 K4 K1 K2 K3 N

STAR-DELTA MODE OPERATION 5 42 The fan motor turns by slow speed, as supplied at star voltage K1 K1 K2 K1 = = 45 K4 K3 K2 K4 K1 K2 K3 N

STAR-DELTA MODE OPERATION 5 42 K1 Few seconds later two contacts of the relay K4 (it’s a slow operating relay) change their position K1 K2 K1 = = 45 K4 K3 K2 K4 K1 K2 K3 N

STAR-DELTA MODE OPERATION 5 42 K1 Few seconds later two contacts of the relay K4 (it’s a slow operating relay) change their position K1 K2 K1 = = 45 K4 K3 K2 K4 K1 K2 K3 N

STAR-DELTA MODE OPERATION 5 42 K1 Few seconds later two contacts of the relay K4 (it’s a slow operating relay) change their position K1 K2 K1 = = 45 K4 K3 K2 K4 K1 K2 K3 N

STAR-DELTA MODE OPERATION 5 42 The fan motor turns by high speed, as supplied at delta voltage K1 K1 K2 K1 = = 45 K4 K3 K2 K4 K1 K2 K3 N