Insulation Requirement According to IEC60950
安規距離計算-1 直線及沿面 直線距離:Clearance distance = CL 定義:任何可能之最短路徑,且CL≦CR。 沿面距離:Creepage distance = CR 定義:攀爬物體表面之最短路徑。
安規距離計算-1.1 直線及沿面 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CL/CR的計算方式如下: 利用開槽來延伸CR,則X必須大於1 mm,例:
安規距離計算-2 工作電壓決定距離 AC to DC Product, <=150Vac CL: 輸入電壓≦150Vac的產品,例如輸入為100-127Vac,其基準值為: B/I = 1.0mm R/I = 2.0mm; 若Peak電壓高於210Vpk,則必須加上其額外值! 如右圖: 例:Vpk=302,則 B/I = 1.0 + 0.2 = 1.2 mm R/I = 2.0 + 0.4 = 2.4 mm
安規距離計算-3 工作電壓決定距離 AC to DC Product, <=300Vac CL: 輸入電壓>150Vac ≦300Vac的產品, 例如輸入為100-127Vac/200-240Vac or 100-240Vac,其基準值為: B/I = 2.0mm R/I = 4.0mm; 若Peak電壓高於420Vpk,則必須加上其額外值! 如右圖: 例:Vpk=604,則 B/I = 2.0 + 0.3 = 2.3 mm R/I = 4.0 + 0.6 = 4.6 mm
安規距離計算-4 工作電壓決定距離 DC to DC Product, <=210Vdc CL: 輸入≦210Vdc的 DC to DC Converter, 例如輸入為36 to 75Vdc,則基準值為: B/I = 1.0mm R/I = 2.0mm; 如右圖: 例:Vdc=96,則 B/I = 1.0 mm R/I = 2.0 mm
安規距離計算-5 操作高度與直線距離之關係 依據研究及IEC60664-1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安規要求,如下圖,以海拔10,000英呎(3,048公尺)為例,最終直線距離CL必須乘上海拔係數1.15倍。
安規距離計算-6 工作電壓決定距離 Creepage (CR): 沿面距離 沿面距離可使用線性內插法。 !點入試算
安規距離計算-6.1 線性內插法。 例如: Vrms = 280時,沿面距離為3.0mm. 內插法通常定義爲根據”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。
總結 A.CL要依據以下來確定: B.CR 要依據以下來確定: 絕緣類型 INPUT VOLTAGE RANGE; WORKING VOLTAGE (Vpeak); Pollution Degree;(Delta select Pollution Degree 3.); Altitude; 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: 絕緣類型; WORKING VOLTAGE (Vrms); Pollution Degree;(Delta select Pollution Degree 2.); Material Group; 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 - Markings Performance - Temperature - Abnormal Tests Electric Strength Test 1
Requirements of Construction - Materials UL/CSA - Appropriate Insulation System 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 60085 Material of the lowest temperature rating dominates UL R/C materials accepted, e.g. tapes, bobbins.
Requirements of Construction – Materials (con’d)
Requirements of Construction – Insulation General – Based on Working Voltage - Clearance: (based on Vpk) A = Minimum value from Table 2H(page29), according 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 Vpk A = 4 mm, B = 0.6 mm Determined clearance = 4.6 mm Exception: If working environment of altitude above 2000 m is specified, Annex G shall be considered.
Requirements of Construction – Insulation (con’d) Example of Creepage Determination: 1. Measured working voltage = 360 Vrms 2. Pollution Degree 2 3. Material Group II Required creepage distance = 2X From Table 2L: (400 – 300)/(2.8-2.2) = (360 – 300)/(X-2.2) X = 2.56 ≒ 2.6 Required creepage = 5.2 mm
Requirements of Construction – Insulation (con’d) 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 Insulation) 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 (con’d) 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 shall keep Reinforced Insulation from core.
Requirements of Construction – Marking Company name or trade mark “E115982” Factory Location “DCGM” “DET” “DEIC” “DEIT” “DCWM” System Designation “MP-130B” “MP-130G” “MP-130I” … etc.