【正文】 電阻值大小，可具體分下述三種情況進行鑒別： According to the measured resistance value of the size of the specific points of the following three conditions can be identified: A 被測色碼電感器電阻值為零，其內部有短路性measured color code inductor resistance value is zero, the internal short circuit 被測色碼電感器直流電阻值的大小與繞制電感器線圈所用的漆包線徑、繞制圈數有直接關系，只要能測出電阻值，則可認為被測色碼電感器是正measured color code inductor DC resistance of the size and wound inductor coil used enameled wire diameter, winding number of turns is directly related to, as long as the value of measured resistance, you can color code that the measured inductor is normal The. 2  weeks transformer testing A 將萬用表撥至 R1 擋，按照中周變壓器的各繞組引腳排列規(guī)律，逐一檢查各繞組的通斷情況，進而判斷其是The multimeter to the R 1 block allocated in accordance with the various transformer windings in weeks pinlaws, one by one to check the windingoff situation, and then determine whether it is 檢測絕緣testing insulation 將萬用表置于 R10k 擋，做如下幾種狀態(tài)測試：will be placed in R 10k block multimeter, do the following several states test: (1) 初級繞組與次級繞組之間的電阻值；(1) between the primary winding and secondary winding resistance value。 (2) 初級繞組與外殼之間的電阻值；(2) the primary winding and the resistance value between the shell。 (3) 次級繞組與外殼之間的電阻值。(3) secondary winding and the resistance value between the shell. 上述測試結果分出現三(1) 阻值為無窮大：正常；(4) The resistance is infinity: normal。 (2) 阻值為零：有短路性故障；(5) Resistance to zero: There is shortcircuit fault。 (3) 阻值小于無窮大，但大于零：有漏電性故障。(6) The resistance is less than infinite, but greater than zero: There is leakage faults. 3 電源變壓器的檢測3. power transformer testing A 通過觀察變壓器的外貌來檢查其是否有明顯異常By observing the appearance of the transformer to check there is an obvious anomaly. 如線圈引線是否斷裂，脫焊，絕緣材料是否有燒焦痕跡，鐵心緊固螺桿是否有松動，硅鋼片有無銹蝕，繞組線圈是否有外露等。 Such as the coil wire is broken, Sealingoff, insulation materials, whether there are scorch marks, whether the core fastening screw loose, whether silicon steel corrosion, whether there are exposed coil windings, etc.. B 絕緣性測試。insulation testing. 用萬用表 R10k 擋分別測量鐵心與初級，初級與各次級、鐵心與各次級、靜電屏蔽層與衩次級、次級各繞組間的電阻值，萬用表指針均應指在無窮大位置不動。 R 10k block with the multimeter were measured core and primary, primary with the secondary, with the subcore, electrostatic shielding layer and panties secondary, secondary resistance between the windings, multimeter pointer refers to the infinity position should not action. 否則，說明變壓器絕緣性能不良。 Otherwise, it shows bad transformer insulation. C 線圈通斷的檢測。coiloff detection. 將萬用表置于 R1 擋，測試中，若某個繞組的電阻值為無窮大，則說明此繞組有斷路性故障。 Will be placed in R 1 block multimeter, test, if a winding resistance value infinite, then there are the winding circuit failures. D 判別初、次級線圈。determine the beginning of secondary coil. 電源變壓器初級引腳和次級引腳一般都是分別從兩側引出的，并且初級繞組多標有 220V 字樣，次級繞組則標出額定電壓值，如 15V 、 24V 、 35V 等。 Power transformer primary and secondary pins pins are usually respectively from both sides of the leads, and marked with the 220V primary winding multiword, the subwindings are marked rated voltage value, such as 15V, 24V, 35V and so on. 再根據這些標記進行識別。Then according to these tags to identify. E 空載電流的檢測。 noload current detection. (a) 直接測量法。direct measurement method. 將次級所有繞組全部開路，把萬用表置于交流電流擋 (500mA ，串入初級繞組。當初級繞組的插頭插入 220V 交流市電時，萬用表所指示的便是空載電流值。此值不應大于變壓器滿載電流的 10 ％～ 20 ％。一般常見電子設備電源變壓器的正常空載電流應在 100mA 左右。如果超出太多，則說明變壓器有短路性故障。 (b) 間接測量法。在變壓器的初級繞組中串聯(lián)一個 10  /5W 的電阻，次級仍全部空載。把萬用表撥至交流電壓擋。加電后，用兩表筆測出電阻 R 兩端的電壓降 U ，然后用歐姆定律算出空載電流 I 空，即 I 空 =U/R 。 F 空載電壓的檢測。將電源變壓器的初級接 220V 市電，用萬用表交流電壓接依次測出各繞組的空載電壓值 (U21 、 U22 、 U23 、 U24) 應符合要求值，允許誤差范圍一般為：高壓繞組≤177。 10 ％，低壓繞組≤177。 5 ％，帶中心抽頭的兩組對稱繞組的電壓差應≤177。 2 ％。 G 一般小功率電源變壓器允許溫升為 40 ℃～ 50 ℃，如果所用絕緣材料質量較好，允許溫升還可提高。 H 檢測判別各繞組的同名端。在使用電源變壓器時，有時為了得到所需的次級電壓，可將兩個或多個次級繞組串聯(lián)起來使用。采用串聯(lián)法使用電源變壓器時，參加串聯(lián)的各繞組的同名端必須正確連接，不能搞錯。否則，變壓器不能正常工作。 I. 電源變壓器短路性故障的綜合檢測判別。電源變壓器發(fā)生短路性故障后的主要癥狀是發(fā)熱嚴重和次級繞組輸出電壓失常。通常，線圈內部匝間短路點越多，短路電流就越大，而變壓器發(fā)熱就越嚴重。檢測判斷電源變壓器是否有短路性故障的簡單方法是測量空載電流 ( 測試方法前面已經介紹 ) 。存在短路故障的變壓器，其空載電流值將遠大于滿載電流的 10 ％。當短路嚴重時，變壓器在空載加電后幾十秒鐘之內便會迅速發(fā)熱，用手觸摸鐵心會有燙手的感覺。此時不用測量空載電流便可斷定變壓器有短路點存在。 All the secondary winding of all the open, the AC current meter placed in block (500mA, string into the primary winding. When the primary winding of the plug into 220V AC electricity, the meter is indicated by noload current value. This value should not be transformer full load current is greater than 10% ~ 20%. the general mon electronic devices power transformer should be the normal load current of about 100mA. If you exceed too much, then power transformer shortcircuit failures. indirect measurement. In the transformer primary winding in series a 10 / 5W resistor, the sub is still all empty. the multimeter to AC voltage block allocation. added power, you use two tables resistance R T measured voltage drop across the U, and then use Ohm39。s law calculate the load current I empty, that is, I empty = U / R. F noload voltage detection. will be the primary power transformer 220V electricity access, use multimeter measuring AC voltage,then turn out the windingload voltage (U21 , U22, U23, U24) should meet the requirement values, allowable error range is typically as follows: highvoltage winding ≤ 177。 10%, lowvoltage winding ≤ 177。 5%, with a centertapped windings of the two sets of symmetrical voltage difference should be ≤ 177。 2%. G general low power power transformer to allow temperature rise 40 ℃ ~ 50 ℃, if the use of good quality insulation materials, allowing temperature can be increased. H test discriminant end of each winding of the same name. in the use of power transformers, sometimes in order to get the required secondary voltage can be two or more secondary windings together in series to use. using tandem Law uses the power transformer, the participants in series of the same name each winding terminal must be properly connected, can not be wrong. Otherwise, the transformer can not be normal work. I. power transforme