Distribution Cabinet Installation And Acceptance: Key Points For Checking The Consistency Of The Center Lines Of The Moving And Fixed Contacts
During the installation and handover acceptance of complete sets of power distribution cabinets, the contact alignment problem of Powbinet is often a key factor affecting the long-term operational reliability of the equipment. According to the "Code for Acceptance of Construction Quality of Building Electrical Engineering," handcart-type or drawer-type switchgear should operate smoothly and without obstruction during push-pull operations. A key indicator is that the center lines of the moving and stationary contacts should be aligned, and the contacts should have tight contact. This requirement directly affects the conductivity and temperature rise control of the equipment in the closed state.
Installation Accuracy and Torque Control
For the installation of fixed contacts inside the switchgear, construction personnel need to pay close attention to the horizontal and vertical deviations between the three phases. In actual operation, the terminals of the fixed contacts must be checked with a torque wrench during tightening to prevent contact position displacement due to loose bolts. In on-site acceptance practice, the company re-checks the torque of all fastening bolts in the switchgear's conductive circuit. If any bolts are found to have unqualified torque, the construction unit is required to retighten them all to ensure accurate alignment of the contact center lines. When the circuit is closed, the contact finger must precisely rest on the fixed contact of the disconnector switch. Inspectors can use tools such as a welding mirror and a flashlight to observe the contact overlap.
Drawer Cabinet Secondary Circuit Inspection
For the secondary circuit section of the drawer-type distribution cabinet, the inspection of the fixed contacts requires even greater detail. During troubleshooting, the maintenance team typically checks the wiring specifications of each cabinet and circuit, focusing on identifying potential issues such as contact oxidation, poor contact, and abnormal signal transmission. For control modules and auxiliary contacts in the secondary circuit, workers need to verify the uniformity of the spring pressure of each set of fixed contacts and observe the contact surface for any burn marks. If a centerline deviation of the fixed contact is found, it can be corrected by adjusting the level of the drawer base or correcting the installation position of the guide rail until the contacts are in tight contact with no obvious indentation differences. According to specifications, a full inspection can effectively prevent partial discharge or excessive contact resistance caused by inconsistent contact centering.
