绝缘距离的计算 (1)

1、Insulation Requirement According to IEC60950 直線距離：直線距離：Clearance distance = CL定義：任何可能之最短路徑，且定義：任何可能之最短路徑，且CLCR。 沿面距離：沿面距離：Creepage distance = CR定義：攀爬物體表面之最短路徑。定義：攀爬物體表面之最短路徑。 如果導體之間利用絕緣作為阻隔，但是在無法確保兩個不如果導體之間利用絕緣作為阻隔，但是在無法確保兩個不同物質間之連結性，故其同物質間之連結性，故其CL/CR的計算方式如下：的計算方式如下： 利用開槽來延伸利用開槽來延伸CR，則，則X必須大於必須大於1

2、mm，例：，例： CL：輸入電壓輸入電壓150Vac的產的產品，例如輸入為品，例如輸入為100-127Vac，其基準值為：，其基準值為：B/I = 1.0mm R/I = 2.0mm；若若Peak電壓高於電壓高於210Vpk，則必須加上其額外值！則必須加上其額外值！如右圖：如右圖：例：例：Vpk=302，則，則B/I = 1.0 + 0.2 = 1.2 mmR/I = 2.0 + 0.4 = 2.4 mmCL：輸入電壓輸入電壓150Vac 300Vac的產品，的產品，例如輸入為例如輸入為100-127Vac/200-240Vac or 100-240Vac，其基，其基準值為：準值為：B/I =

3、 2.0mm R/I = 4.0mm；若若Peak電壓高於電壓高於420Vpk，則，則必須加上其額外值！必須加上其額外值！ 如右圖：如右圖：例：例：Vpk=604，則，則B/I = 2.0 + 0.3 = 2.3 mmR/I = 4.0 + 0.6 = 4.6 mm CL：輸入輸入210Vdc的的DC to DC Converter，例如輸入為例如輸入為36 to 75Vdc，則基準值為：則基準值為：B/I = 1.0mm R/I = 2.0mm；如右圖：如右圖：例：例：Vdc=96，則，則B/I = 1.0 mmR/I = 2.0 mm 依據研究及依據研究及IEC60664-1的規範，越高海

4、拔的大氣壓力的規範，越高海拔的大氣壓力越小，所以必須加長直線距離，用以符合原始所需之越小，所以必須加長直線距離，用以符合原始所需之安規要求，如下圖，以海拔安規要求，如下圖，以海拔10,000英呎英呎(3,048公尺公尺)為例，為例，最終直線距離最終直線距離CL必須乘上海拔係數必須乘上海拔係數1.15倍。倍。 沿面距離可沿面距離可使用線性內使用線性內插法。插法。Vrmsor VdcLow limitVrmsHigh limitVrmsRequestCR (B/I)3763004003.8Low limitCRHigh limitCRRequestCR (R/I)3.247.6！點入試算！點入試算

5、線性內插法。線性內插法。內插法通常定義爲根據內插法通常定義爲根據”二個已知值估計出中間值二個已知值估計出中間值”。線性內插法在二個已知資料點間畫一條直線，新的資料線性內插法在二個已知資料點間畫一條直線，新的資料點就位於這條直線上，具體位置要根據其值與二個端點點就位於這條直線上，具體位置要根據其值與二個端點之一的接近程度確定。之一的接近程度確定。 ScVcVaVcVbScSaxf)()()()(例如: Vrms = 280時,沿面距離為3.0mm.5 . 2)250300()250280()5 . 22 . 3()(xf查表2H,2J及2L取得沿面(CR)及直線距離(CL)traceinsula

6、tionCRCLA-CBasic2.882.0C-EReinforced4.764.0B-EReinforced6.204.0+0.2A-BBasic2.582.0A-DBasic2.382.0B-CFuntional2.401.5+0.1C-DFunctional3.611.5+0.1A-FBasic2.402.0若兩點間的RMS電壓小於AC INPUT MAX. VOLTAGE,則兩點取MAX. INPUT VOLTAGE總結A.CL要依據以下來確定:1.絕緣類型2.INPUT VOLTAGE RANGE;3.WORKING VOLTAGE (Vpeak);4.Pollution Degr

7、ee;(Delta select Pollution Degree 3.);5.Altitude;6.計算方法:CL=A+B (A: Minimum value from Table 2H, according to the mains voltage; B: Additional value from Table 2J, according to the actual peak working voltage,A,B取值應看大)B.CR 要依據以下來確定:7.絕緣類型;8.WORKING VOLTAGE (Vrms);9.Pollution Degree;(Delta select Poll

8、ution Degree 2.);10. Material Group;11. 計算方法:利用Table 2L已知兩點列直線方程求中間點.Safety Requirements for Transformers Construction- Materials - Insulation - MarkingsPerformance- Temperature - Abnormal Tests - Electric Strength Test 1Requirements of Construction - Materials UL/CSA - Appropriate Insulation System

9、 shall be adopted - UL R/C according to UL1446- Depending on temperature performance requirement of different applications (Class B, Class F, etc.)- Materials limited to the Insulation System Other Certifiers No “Insulation System” requirement- Classification of insulation materials according to IEC

10、 60085- Material of the lowest temperature rating dominates- UL R/C materials accepted, e.g. tapes, bobbins.Requirements of Construction Materials (cond) Requirements of Construction Insulation General Based on Working Voltage- Clearance: (based on Vpk) A = Minimum value from Table 2H(page29), accor

11、ding to the mains voltage B = Additional value from Table 2J(page30), according to the actual peak working voltage Required clearance = A + B- Example: 1. Equipment rated 100-240 Vac 2. Measured maximum working voltage 600 VpkA = 4 mm, B = 0.6 mmDetermined clearance = 4.6 mm-Exception: If working en

12、vironment of altitude above 2000 m is specified, Annex G shall be considered. Requirements of Construction Insulation (cond)Example of Creepage Determination:1. Measured working voltage = 360 Vrms2. Pollution Degree 23. Material Group IIRequired creepage distance = 2X From Table 2L: (400 300)/(2.8-2

13、.2) = (360 300)/(X-2.2)X = 2.56 2.6 Required creepage = 5.2 mm Requirements of Construction Insulation (cond)Wound Components Triple-Insulated Wires- Minimum 3 construction layers shall apply for Reinforced Insulation - Passes Annex U tests (Insulated Winding Wires for Use Without Interleaved Insula

14、tion)- Where two wires cross each other at an angle between 45 - 90 , an additional physical separation shall be provided, e.g. by sheet material. 45 - 90 Requirements of Construction Insulation (cond)Core- Usually considered as “floating” all surrounding components shall keep Basic/Supplementary Insulation from core. - Some considered as primary/secondary all components on opposite side sh