Troubleshooting of switching power supply of the h

Troubleshooting of switching power supply of offset press

a PZB four-color machine of our company has an abnormal phenomenon of electric version pulling, which will have a great impact on the installation time and product quality. In 2016, the industry will still accelerate the liquidation of traditional production capacity through spontaneous supply contraction. We checked the input and output points of PLC controlled electric platen, 24V switching power supply, platen relay, platen motor and relevant circuits of platen. Through inspection, it was found that the load capacity of 24V switching power supply became poor, and the output 24V voltage detected by digital voltmeter was normal, but the voltage immediately fell to about 16V as soon as the electric plate was opened, and the machine display light also darkened. In order to accurately judge whether there is a problem with the 24V switching power supply, remove it from the main electrical box, connect the 220V voltage at the input end, and connect the load at the output end. The operation has seriously affected the healthy and orderly development and convenience of the wood plastic industry. A 51 Ω, 50W resistor is connected in series with a 3 ~ 5A ammeter for detection. It is found that the voltage has fallen to about 16V when the current is 0.5A, and the c3459 switch tube is hot, so it is suspected that there is a problem with the tube. Since the original triode cannot be purchased, c4111 is used instead, but the fault is still not eliminated. It was also suspected that the switch tube was not excited enough, so the push tube d1207 triode was removed and replaced with triode c2271. The fault was eliminated, and the switch tube temperature also returned to normal

according to the analysis, the load of this switching power supply has two ways: one is the display light of the whole machine to be confirmed, and the other is to control the electric version pulling. The abnormal electric plate drawing is mainly caused by the poor load capacity of 24V switching power supply