Instruction manual

KRB-5377

4-2. Draw-out and Insertion Operation

4-2-1. General

The draw-out type ACB consists of the breaker body and the draw-out cradle. The main and control circuit terminals are installed on

the draw-out cradle, which permits you to draw out and inspect or service the breaker body without the need for removing wiring

from the terminals.

The draw-out mechanism allows you to move the breaker body to any of the four positions as shown in Fig. 28. The switchboard

panel door can be shut with the breaker body drawn out to the CONN., TEST or ISOLATED position.

1. CONN. position 4. Removed position

In this position, the main circuit and the control

circuits of the ACB are connected to the external The breaker body is removed from the draw-out

circuits for normal service. cradle.

Draw-out Insert Insert Draw-out

2. TEST position 3. ISOLATED position

Insert

Draw-

out

In this position, the main circuit is isolated, and the In this position, both the main and control circuits

control circuits are connected. The ACB can be are isolated, and the ACB is completely de-energized.

tested with the switchboard panel door closed. The switchboard panel door can be closed.

Fig. 28 Positions of breaker body in draw-out cradle

z Operation Durability

The AR series ACBs are designed to ensure the operation durability of 100 draw-out and insertion cycles in conformance to IEC

60947-1 and JIS C8201-2 (one cycle means that the breaker body is drawn out from the CONN. position to the Removed position

and inserted back to the CONN. position). Draw-out and insertion operation of more than 100 cycles could abrade the main circuit

contacts, resulting in an overheat of the contacts during energization.

Draw-out cradle

Main circuit

contact

Control circuit

contact

Breaker body

Rollers Draw-out rail

Position indicato