Eaton Power Circuit Breaker MDS-C12

Ensure the following conditions for Fixed Device

Ensure the following conditions for Drawout Device

Remove the drawout circuit breakers from the cassette

Remove all primary and secondary power for fixed mounted circuit breakers

Verify breaker operation by charging, closing, recharging, and opening the breaker

Mechanical Interlock Verification

Charge the breaker mechanism springs

Close the breaker by applying rated voltage to the spring release accessory

Verify closing by noting the state of the indicating flag

Charge the breaker mechanism springs again

Disconnect power to the motor operator to prevent automatic recharging

Is the pop-out trip indicator 'out'?

Remove arc chute screws and all arc chutes from the arc chamber.

Turn each arc chute upside down and visually inspect the inside.

Inspect for erosion and sooty discoloration on the splitter plates and insulating jacket.

Do arc chutes show severe signs of erosion or discoloration?

Replace with a new arc chute if severe signs of erosion or discoloration are present.

Pre-inspection conditions for Fixed Device

Pre-inspection conditions for Drawout Device

Check for nicked wires, cracks in plastic parts, and loose screws

Tighten screws or bolts to levels outlined in Table 22

Apply thread-locking compound to loose screws in plastic parts

Replace or repair all nicked wiring according to industry practices

Ensure torque values are within recommended values

Check torque values of the operating mechanism

Charge the breaker mechanism springs

Press the ON pushbutton to close the breaker manually

Verify closing by noting the state of the indicating flag (Figure 93)

Charge the breaker mechanism springs again

Disconnect power to the motor operator to prevent automatic recharging

Press the OFF pushbutton to manually open the breaker

Press the ON pushbutton to manually close the breaker