Line contact force calculation

1. I feel that you can find the videos and basic ability calculation of teaching on the Internet. The most important thing is to practice more.

2. When the rod is in direct contact with the ground, both of them belong to smooth surface constraint, and the direction of constraint reaction force is along the normal line of the contact surface to the rod.

3. It's not calculated as you think. There's a special formula. Check the gear manual.

4. It's about how to store the cable in peacetime. Don't fold the data cable casually, it's better to roll it into a ring and fasten it with a tie rope, which can extend the service time to a great extent.

5. Contact point contact is generally, the line contact is directly, cross
line contact is generally a plane contact.

6. Point contact means point to point contact and point to face contact, line to line contact means line to line contact and line to face contact, and face to face contact means face to face contact

7. Poor contact of circuit: such as poor contact of lamp holder, switch and hanging box; Poor contact of fuse; Poor contact at the line joint, etc. In this way, the lights will turn on and off, and the electrical appliances will not work normally. Fault caused by wrong connection of the circuit itself: for example, the two terminals of the socket are all connected to the live line or the zero line; The switch is wrongly connected to the live wire in the main line; The bulbs are connected in series in the circuit
what should we do in the above situations? First of all, learn to use the test pen. When the measuring pen is placed on the main switch, if there is electricity, then the lamp cap is connected in parallel with the two terminals under the knife switch. At this time, the lamp is on, indicating that the household wire is normal. If the light doesn't work, it means that the door line is open. Just repair the door line
after that, check the live wire in each branch with a measuring pen. If the neon tube does not emit light, it indicates that the live wire in this branch is open, and the live wire should be repaired; If the neon tube lights up when the measuring pen is used in each branch, then the lamp cap is connected to each branch respectively for inspection. If the lamp of which branch is not on, it means that the zero line of this branch is open and needs to be repaired
then, remove the fuse box cover on the trunk road, and connect the calibration lamp cap to the upper and lower ends of a fuse. If the lamp is on at this time, it means there is a short circuit. Similarly, connect the calibration lamp cap in series with the above method on the contact of each branch switch. When the lamp is connected to the branch, it will be on, indicating that the branch is short circuited
at this time, as long as the branch is overhauled, the line fault can be easily solved.

8. The phenomenon of abnormal color appears

9. Gear meshing, two gear tooth profile contact is the contact line; The contact area refers to the area where a tooth profile is on the actual meshing line, from the tooth into meshing to the tooth out of meshing.

10. Check the following steps:
1. Whether the grounding resistance of grounding wire meets the requirements; It is mainly used to prevent electric shock caused by exposure of electric shell; Generally less than 4 ohm
2; Check if there is any short circuit in the zero line and live line, and carry out the withstand voltage test if possible
3. Whether the diameter of the live wire of the zero line is enough or not, the wall laying should be larger, and the insulation should have better aging resistance, because the heat dissipation is not good, and it is not easy to replace and find problems
4. If the circuit breaker is selected properly, if it is too large, it can't protect the electrical appliances, and if it is too small, it will trip frequently. Generally, it can choose about 1.1-1.2 times of the rated line; Leakage protection should also be tested

if you want to check the contact resistance, the multimeter test is not very accurate, and the general lap may also show that the resistance is very small, so it is better to pay attention to the installation process. Before wiring, check the whole coil of wire to see if there are any quality problems such as insulation skin damage and wire breakage in the middle; When wiring, connect it firmly, and handle the end of the line better. If you have the conditions, you can measure the whole milliohm level resistance meter, then you can really test whether the contact is good

some humble opinions are for reference only.