263

SF

The table below shows the state of the other contacts when the current through the welded form “a” contact is 0 V and the rated volt-

age is applied through the form “b” contact.

Contact Operation Table

No.4

No.3

No.1

No.2

Contact No.

No.1

No.2

No.3

No.4

Terminal No.

11–12

7–8

5–6

9–10

State of other contacts

1234

Welded

terminal

No.

1

>0.5

2

>0.5

3

>0.5

>0.5

>0.5

4

>0.5

Note: Contact gaps are shown at the initial state.

If the contacts change state owing to loading/breaking

it is necessary to check the actual loading.

Empty cells: either closed or open

Contact No.

Contact No.

If the No. 3 contact welds.

Each of the two form “a” contacts (Nos. 1, 2, and

No.4

No.3

No.1

No.2

Non-energized

No.4

No.3

No.1

No.2

Energized (when no. 3 contact is welded)

When the form “a” contacts (nos. 1, 2, and 4) weld, the armature remains in a non-returned state and the contact gap at the single

Form “a” Contact Weld

If the No. 2 contact welds.

The single form “b” contact (No. 3) maintains a

No.4

No.3

No.1

No.2

Energized

No.4

No.3

No.1

No.2

Non-energized (when no. 2 contact is welded)

2) 3a1b Type

If the form “b” contact (No. 3) welds, the armature becomes non-operational, the contact gaps at the three form “a” contacts are

Form “b” Contact Weld