Improvement 2 of DW10M-200, 400, 600 type demagnetization switch control circuit

(3) Improvement 2 of DW10M-200, 400, 600 type excitation switch control circuit.
    When the original circuit is in normal operation, the following abnormal phenomena often occur: ① After the excitation switch is closed, the red light H2 indicates
normal, The green light Hi is still flashing; ② When the closing of the excitation switch fails, the re-closing operation cannot be carried out
. The re-closing operation can only be carried out after removing the operating fuse and de-energizing the time relay KT.
    This is caused by the low return voltage of the time relay KT. For this reason, the original circuit can be improved, as
shown in Figure 7-58. Utilize the preparatory closing contacts 21 and 22 of the operating switch SA to change the delayed opening normally closed contact of the original KT to a delayed
opening normally open contact . The time limit is 2s, which not only ensures sufficient closing time but also prevents the switch from jumping.