Motorcycle Carbon Brush accident measures have several measures
(1) motorcycle brush balance three-phase load, so that the neutral current to minimize: According to operational experience, the majority of neutral wire break is the joint blown, the main reason is the neutral current is too large. To reduce this current, the three-phase load must be balanced as much as possible.
"Motorcycle Carbon Brush operating procedures" and Motorcycle Carbon Brush manufacturing standards are provided Y. ynO wiring Motorcycle Carbon Brush neutral line current shall not be greater than the motorcycle brush brush rated current of 25%. To meet this requirement, the motorcycle motorcycle brush secondary output current imbalance should generally be less than 20% .The actual operation of the Motorcycle Carbon Brush, three-phase imbalance are mostly high, and some are a few times , The harm is obvious. Motorcycle Carbon Brush
In addition, some people think that with the "imbalance" is difficult to accurately reflect the neutral point of displacement, and therefore put forward to the actual calculation method to judge, more appropriate. The calculation method is: first use the neutral point displacement voltage formula, calculate the neutral point displacement voltage U00 '; and then find the neutral point after the displacement of the three-phase load voltage, and finally compared with the rated voltage to determine whether the program (Ie + 5% and 10% of the rated voltage of the receiver).
(2) to increase the neutral wire cross-section: "overhead distribution line design technical regulations" provides that the three-phase four-wire neutral line section can choose a smaller phase cross-section of the wire, but not less than the phase line of 50 %. However, taking into account the neutral current may sometimes be equal to the actual phase current phase, it is recommended to use the same line with the same line, should not use small cross-section wire. This can prevent the disconnection and reduce the line loss, reduce the pressure drop, but also facilitate the construction of materials and maintenance management, investment increased limited. In addition, the neutral line should be multi-stranded wire.
(3) to eliminate copper and aluminum joints: motorcycles carbon brush casing and secondary knife, insurance and other joints are mostly copper, and the current use of wire mostly naked aluminum wire. Formed a lot of copper and aluminum joints, water Or moisture easily lead to electrochemical corrosion, resulting in poor contact joints, or even overheating and blown. Therefore, from the motorcycle brush tube to the knife and the fuse of the short section of the wire, should use the copper wire, and the trunk line connection using copper and aluminum transition clamp.
(4) do a good job of repeated grounding: This is an important technical measures, but also the first three supplementary measures. The specific approach is: in addition to the motorcycle brush table at the neutral point of the ground point, in the main branch of the main line and the end of the main line should be assisted by grounding, the best in each residential building line population Also do repeat the ground point. Once the connector is disconnected, minimize neutral displacement, reduce the voltage rise, reduce the degree of harm.
When the neutral line is broken at point d, the neutral current flows to the Ro by repeating the grounding element R1, thus limiting the displacement of the neutral voltage, thus ensuring the safe operation of the electrical equipment.
(5) to prevent the phase line and the neutral line after the wrong: usually stipulates that the neutral line in the crossbar occupies a certain position and make each staff master. Generally can be set to face the direction of the increase in the direction of the left side of the second line for the neutral line, the neutral line of the best use of porcelain vase with a different phase of the color, so that it is not easy to connect the wrong line. line.
(6) Neutral lines do not install switches and fuses: "rural low-voltage power technical regulations) provides that the zero line at the same time as a ground circuit, should not be installed in the zero line circuit switches and fuses. To prevent the zero line disconnected, resulting in the phase load voltage drop is not balanced.
(7) to strengthen the maintenance management: the operation of the Motorcycle Carbon Brush to strengthen the operation and management, the establishment of a practical operation and management system, timely measurement and adjustment of three-phase unbalanced load; quarterly check a connector, Refurbished once, eliminate the oxide layer, find the problem in time to eliminate.