When the power plate is not powered, the highest rate of damage is associated with the insurance resistance (restricted current resistance) at the main power/support power input end, but it is almost never individually damaged and the direct replacement immediately burns again and must first be screened and repaired for the second stage of short circuit failure。
I, recognize this "failable resistance."
1. Appearance: most cycling resistance, usually 1 ~ 47, with power of 1/2 w ~ 2 w, mostly in grey, blue or brown。
2. Location: close to the safety tube (fuse), chained at the output end of the whole stream bridge, at the switch/mos pipe, or at the power input end of the auxiliary power supply ic。
3. Designation: the plate is regularly marked with fr, f, rxx (e. G. Fr 101, r001) and is partially marked with the word "insurance resistance"。
Ii. Why can't they be replaced directly:
The effect of safety resistance is to limit flow + overflow protection, and it burns because of short circuits or severe overflows of late-grade circuits, which are "recipients" rather than "causes"。
1. Direct replacement: new electrical resistance will melt immediately and even blow up the switch, burn the power source ic, burn the safety tube and extend the failure range。
2. More dangerous operations: there can be absolutely no short/replacement of copper wires, guide wires or general electrical resistance, loss of transient protection, high risk of burning and even fire of components。
Iii. Correct maintenance steps:
1. Safety first step: power outage。
When power plugs are removed, high-pressure short-pressure filtered large electrolytic caps (around 400v/100 mf) will be used to discharge the power for three to five seconds to avoid high voltage。
2. Dismantling of damaged insurance electrical resistance。
Make sure they're open (inexhaustible) without rushing to reload。
3. Focus on rear-class short circuit elements (in order of probability of failure)
Test machine validation (key fire-proofing steps)
After confirming that there are no short circuits at the back stage, do not directly load the tube, but rather join a 100 w incandescent light bulb at the safety tube position:
(1) the light bulb will be extinguished as soon as it is lighted, indicating that the circuit is normal and that the light bulb may be used to re-load the fuse tube and the new generic safety barrier。
(2) light bulbs are frequently lit, indicating that short circuits are still in place, electricity is cut off immediately and troubleshooting continues。
5. Replacement of the same-specified insurance barrier
Insurance resistance must be used at a level that is completely uniform in value and power and cannot be replaced by general electrical resistance。
Additional maintenance techniques
1. In the event of damage to the switch tube, it is recommended to replace the corresponding driver resistance and power source ic, which are often damaged in combination。
2. Insurance resistance damage to the auxiliary power supply, with emphasis on the screening of the auxiliary power switch and the optical circuit。
3. Upon completion of the repairs, the electron-borne vehicle operated for 10 minutes without an abnormal heat reloading machine for the tectonic elements。
These are just personal points, just for information
