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Manufacturer of Diode Rectifier, Bridge Rectifier, Transistor
WEET KBPC 25.0 AMPS KBPC25005W KBPC2501W KBPC2502W KBPC2504W KBPC2506W KBPC2508W KBPC2510W Glass Passivated Bridge Rectifiers
Manufacturer:WEET
Product Category:Bridge Rectifiers
Cerficates: Reach,RoHS,ISO
Type:Single Phase Bridge
Mounting Style:Stud Mount
Termination Style:Quick Connect
Package / Case:KBPC
If - Forward Current:25 A
Peak Reverse Voltage:KBPC25005W-50V, KBPC2501W-100V, KBPC2502W-200V, KBPC2504W-400V, KBPC2506W-600V, KBPC2508W-800V, KBPC2510W-1000V
Series:GBPC1510
Packaging:Bulk
Unit Weight:17g
The rectifier bridge encloses the rectifier tube in a shell. Divided into full bridge and half bridge. The full bridge is to seal the four diodes of the connected bridge rectifier circuit together. The half bridge is to seal two halves of two diode bridge rectifiers together. Two bridges can be used to form a bridge rectifier circuit. One half bridge can also form a full-wave rectifier circuit with a center tap on the transformer. Rectifier circuit and operating voltage.
When the power components such as rectifier bridges have high losses (> 4.0W), the natural cooling method cannot meet their heat dissipation requirements. At this time, forced air cooling must be used to ensure the normal operation of the components. When using forced air cooling, two cases can be considered: a) the rectifier bridge does not have a radiator; b) the rectifier bridge has a radiator. 1. The rectifier bridge does not have a radiator. For the case where the rectifier bridge does not have a radiator and forced air cooling is used, the analysis process is the same as natural cooling, except that the thermal resistance of the rectifier bridge shell to the environment and the PCB board are calculated. In the case of heat transfer resistance with the environment, the selection of its heat transfer coefficient should be based on forced air cooling, and its value is usually 20 ~ 30W / m2C. That is:
Therefore, the heat transfer thermal resistance on the surface of the rectifier bridge housing and the heat transfer thermal resistance through the pins are:
The total thermal resistance of the junction-environment of the rectifier bridge is then:
From the above analysis of forced convection cooling without a rectifier bridge, it can be seen that the heat dissipation path through the surface of the rectifier bridge housing is equivalent to the thermal resistance of the heat dissipation through the pins. On the one hand, we can increase the Size to change the heat transfer status of the rectifier bridge. On the other hand, we can also increase the copper coverage on the PCB board to improve the heat transfer between the PCB board and the environment to achieve the heat dissipation capacity of the rectifier bridge.
2. Rectifier bridge with built-in radiator When the rectifier bridge has built-in radiator for forced air cooling to achieve its cooling purpose, the cooling method in this case
Comparing the two cooling methods of natural cooling of the rectifier bridge and forced air cooling with a radiator, the fundamental difference can be found: the role of the radiator greatly improves the thermal resistance between the rectifier bridge housing and the environment. If the contact thermal resistance between the radiator and the rectifier bridge is omitted, combined with the heat transfer analysis of the rectifier bridge without a radiator, we can obtain the thermal resistance of each heat dissipation path of the rectifier bridge with a radiator for cooling as follows: (1), Thermal resistance on the surface of the rectifier bridge case a) Thermal resistance on the front case of the rectifier bridge: same as forced air cooling without radiator:
b) The thermal resistance of the shell on the back of the rectifier bridge:
Assuming the contact thermal resistance of the rectifier bridge and the case is absent, then:; The typical value of selecting the thermal resistance between the radiator and the environment is:
then:
The total thermal resistance of the rectifier bridge through the surface of the housing is:
2) The thermal resistance of the flow bridge through the pins: The thermal resistance at this time is the same as when the rectifier bridge is not forced to cool with a radiator, so:
Therefore, we can get that the total thermal resistance of the rectifier bridge with a radiator for forced air cooling is the parallel thermal resistance of the above two heat transfer paths:
After careful analysis of the above calculation process and the thermal resistance values of each heat transfer path, we can draw the following conclusions when the rectifier bridge is equipped with a radiator for forced air cooling:
① Among the above three heat transfer paths (the heat transfer from the front of the rectifier bridge, the heat transfer from the back of the rectifier bridge through the radiator, and the heat transfer from the rectifier bridge through the pins), the heat resistance of the heat transfer from the back of the rectifier bridge through the radiator is the smallest The thermal resistance through the front of the housing is the largest, and the thermal resistance through the pins is centered; ② Comparing the total thermal resistance of the rectifier bridge and the thermal resistance through the rear heat sink, it can be found that: The thermal resistance is quite comparable to the total thermal resistance of the rectifier bridge. In fact, the conclusion also shows that in this case, the main heat transfer path of the rectifier bridge is performed through the radiator on the back of the housing, that is, most of the losses on the rectifier bridge are discharged through the radiator. The heat dissipation through other means (pins and the front of the case) is very small. ③ Since the heat dissipation condition of the rectifier bridge at this time is closely related to the thermal resistance of the radiator, the size of the thermal resistance of the radiator will directly affect the temperature on the rectifier bridge. It can be seen that when the rectifier bridge parameter table provided by the manufacturer is about the thermal resistance of the rectifier bridge with a radiator, it can only be the junction-case (Rjc) on the back of the rectifier bridge or the total The junction-case thermal resistance (parallel front and back thermal resistance); the junction-environment thermal resistance at this time has no reference value, because it changes significantly with the thermal resistance of the heat sink.
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Written by WEE Technology Company Limited