ABB E1B-A Circuit Breaker

Long delay protection mainly deals with continuous overload of cables and busbars, and the setting value should be combined with the rated load current, cable current carrying capacity, and cabinet temperature. Short delay protection is used to achieve selectivity between upper and lower levels, avoiding main incoming line tripping caused by lower level faults. Instantaneous protection is used to cut off severe short-circuit faults, and the setting value should avoid normal transients such as motor start-up and transformer excitation inrush current. For renovation projects, if the parameters of the old release cannot be read, they should be reset through load calculation and short-circuit current verification, and the old scale cannot be copied directly.

In addition, the auxiliary power supply, trip indication, and reset mode of PR121/P-LSI should also be confirmed before powering on. If the trip cannot be closed after being tripped, it is necessary to first check whether the release is in a fault locked state, whether the reset button is reset, and whether the control circuit is powered on, rather than forcibly operating the mechanism.

Installation and replacement: refer to the checklist for "discontinued module replacement"

In the maintenance of existing equipment, E1B-A 800 is often used as a replacement for spare parts. Before replacement, it is recommended to establish a four-dimensional checklist of "Mechanical Electrical Certification Document".

Mechanical aspect: Check the external dimensions of 296mm × 418mm × 302mm, weight of 40kg, three pole width, fixed hole position, rear horizontal terminal position, distance between busbar holes in the cabinet, insulation partition and operating handle space. Fixed circuit breakers require firm support inside the cabinet, and suitable lifting equipment should be used during transportation to avoid stress on the casing and terminals.

Electrical aspect: Verify the rated current of 800A, three poles, 600V, 42kA breaking capacity, control voltage, number and form of auxiliary contacts, type and setting range of release. If the old cabinet is drawer type, it cannot be directly replaced with a fixed type; If the old cabinet has front wiring, the rear horizontal terminals cannot be directly matched.

Certification aspect: Check if the project requires UL 1066, CE, RoHS, REACH. Lack of corresponding declaration during export equipment or owner acceptance may lead to work stoppage and rectification. The replacement of spare parts should also retain the original product ID, EAN, and new product serial number for asset ledger updates.

In terms of documentation: the product is associated with data sheets, CE conformity declarations, instructions, and other materials. After the replacement is completed, the cabinet's single line diagram, spare parts list, release device setting record, and auxiliary contact wiring diagram should be updated to avoid subsequent maintenance personnel working according to the old diagram.

On site troubleshooting: from 'unable to close' to 'abnormal temperature rise'

1. The circuit breaker cannot be closed. Perform safety isolation and electrical inspection first, confirm that there are no abnormalities, and then check: whether the release is not reset, whether the fault release indicator pops up, whether the closing coil/motor operating power supply is normal, whether the control circuit fuse is blown, whether the auxiliary contacts are interlocked and logically locked, and whether the mechanical energy storage is completed. If it is manual operation, check the status of the energy storage spring and whether the mechanism is stuck. It is strictly prohibited to repeatedly force the switch on without identifying the cause.

2. Frequent tripping. Distinguish between overload, short circuit, and misoperation. Check the trip indication and event records, and verify whether the PR121/P-LSI setting value matches the load; Check whether the starting current of the motor, transformer inrush current, capacitor compensation switching, etc. cause instantaneous or short delay misoperation; Review the selectivity of superior and subordinate protection. If there is no abnormality in the load and the release frequently operates, the power supply, transformer signal, and release body of the release should be checked.

3. The auxiliary contact signal is abnormal. Check the wiring definition, normally open/normally closed status, terminal fastening, and contact capacity of the 4 auxiliary contacts. If the PLC receives the opposite signal, it may be due to the wrong combination of contacts or the circuit breaker position indicator mechanism not being in place. For interlocking circuits, the consistency between the opening and closing positions of the circuit breaker and the action of the auxiliary contacts should be checked simultaneously.

4. Excessive temperature rise or terminal overheating. Focus on inspecting the horizontal terminal busbar connection surface, bolt tightening torque, contact surface oxidation, busbar hole position deviation, and cabinet ventilation. The power loss of each pole of the circuit breaker is about 65W. If there is insufficient heat dissipation or poor connection inside the cabinet, it is easy to form local hotspots. After a power outage, the terminals should be checked for discoloration, insulation aging, busbar burrs, and loose fasteners. After restoring power supply, infrared temperature measurement can be used to compare the three-phase temperature rise.