電動機的絕緣等級

電動機的絕緣等級
人們根據不同絕緣材料耐受高溫的能力對其規定了7 個允許的最高溫度，按照溫度大小排列分別為：Y、A、E、B、F、H 和C。它們的允許工作溫度分別為：90、105、120、130、155、180 和180℃以上。因此，B 級絕緣說明的是該發電機採用的絕緣耐熱溫度為130℃。使用者在發電機工作時應該保證不使發電機絕緣材料超過該溫度才能保證發電機正常工作。電動機的絕緣等級是指其所用絕緣材料的耐熱等級，分A、E、B、F、H 級。允許溫升是指電動機的溫度與周圍環境溫度相比升高的限度。
絕緣的溫度等級       A 級   E 級   B 級   F 級   H 級
最高允許溫度（℃） 105   120    130   155   180
繞組溫升限值（K）   60     75      80    100   125
性能參考溫度（℃） 80      95     100   120   145
絕緣等級為B 級的絕緣材料，主要是由雲母、石棉、玻璃絲經有機膠膠合或浸漬而成的。
電機的絕緣等級與電機的使用溫度有關。在使用溫度確定後，往往會使用至少同級或較高的絕緣材料，以提高電機的使用壽命。比如，常用的B 級電機，其內部的絕緣材料往往是F 級的，而銅線可能使用H 級甚至更高的，來提高其品質。一般為提高使用壽命，往往規定高級絕緣要求，低一級來考核。比如，常見的F 級絕緣的電機，做B 級來考核，即其溫升不能超過120 度（留10 度作為餘量，以避免工藝不穩定造成個別電機溫升超差）

EXEMPTION CERTIFICATE FOR CARGO HOLD FIRE FIGHTING

SOLAS CHAPTER II-2, REGULATION 10
7. FIRE-EXTINGUISHING ARRANGEMENTS IN CARGO SPACES

7.1 FIXED GAS FIRE-EXTINGUISHING SYSTEMS FOR GENERAL CARGO

7.1.1 EXCEPT AS PROVIDED FOR IN PARAGRAPH 7.2, THE CARGO SPACES OF PASSENGER SHIPS OF 1,000 GROSS TONNAGE AND UPWARDS SHALL BE PROTECTED BY A FIXED CARBON DIOXIDE OR INERT GAS FIRE-EXTINGUISHING SYSTEM COMPLYING WITH THE PROVISIONS OF THE FIRE SAFETY SYSTEMS CODE OR BY A FIXED HIGH-EXPANSION FOAM FIRE- EXTINGUISHING SYSTEM WHICH GIVES EQUIVALENT PROTECTION.

7.1.2 WHERE IT IS SHOWN TO THE SATISIFACTION OF THE ADMINISTRATION THAT A PASSENGER SHIP IS ENGAGED ON VOYAGES OF SUCH SHORT DURATION THAT IT WOULD BE UNREASONABLE TO APPLY THE REQUIREMENTS OF PARAGRAPH 7.1.1 AND ALSO IN SHIPS OF LESS THAN 1,000 GROSS TONNAGE, THE ARRANGEMENTS IN CARGO SPACES SHALL BE TO THE SATISFACTION OF THE ADMINISTRATION, PROVIDED THAT THE SHIP IS FITTED WITH STEEL HATCH COVERS AND EFFECTIVE MEANS OF CLOSING ALL VENTILATORS AND OTHER OPENINGS LEADING TO THE CARGO SAPCES.

7.1.3 EXCEPT FOR RO-RO AND VEHICLE SPACES ON CARGO SHIPS OF 2,000 GROSS TONNAGE AND UPWARDS SHALL BE PROTECTED BY A FIXED CARBON DIOXIDE OR INERT GAS FIRE-EXTINGUISHING SYSTEM COMPLYING WITH THE PROVISIONS OF THE FIRE SAFETY SYSTEMS CODE, OR BY A FIRE-EXTINGUISHING SYSTEM WHICH GIVES EQUIVALENT PROTECTION.

7.1.4. THE ADMINISTRATION MAY EXEMPT FROMTHE REQUIREMENTS OF PARAGRAPHS 7.1.3 AND 7.2 CARGO SPACES OF ANY CARGO SHIP IF CONSTRUCTED, AND SOLELY INTENDED, FOR THE CARRIAGE OF ORE, COAL, GRAIN, UNSEASONED TIMBER, NON-COMBUSTIBLE CARGOES OR CARGOES WHICH, IN THE OPINION OF THE ADMINISTRATION, CONSTITUTE A LOW FIRE RISK. SUCH EXEMPTIONS MAY BE GRANTED ONLY IF THE SHIP IS FITTED WITH STEEL HATCH COVERS AND EFFECTIVE MEANS OF CLOSING ALL VENTILATORS AND OTHER OPENINGS LEADING TO THE CARGO SPACES. WHEN SUCH EXEMPTIONS ARE GRANTED, THE ADMINISTRATION SHALL ISSUE AN EXEMPTION CERTIFICATE, IRRESPECTIVE OF THE DATE OF CONSTRUCTION OF THE SHIP CONCERNED, IN ACCORDANCE WITH REGULATION I/12(a)(vi), AND SHALL ENSURE THAT THE LIST OF CARGOES THE SHIP IS PERMITTED TO CARRY IS ATTACHED TO THE EXEMPATION CERTIFICATE.

7.2 FIXED GAS FIRE-EXTINGUISHING SYSTEMS FOR DANGEROUS GOODS
A SHIP ENGAGED IN THE CARRIAGE OF DANGEROUS GOODS IN ANY CARGO SPACES SHALL BE PROVIDED WITH A FIXED CARBON DIOXIDE OR INERT GAS FIRE-EXTINGUISHING SYSTEM COMPLYING WITH THE PROVISIONS OF THE FIRE SAFETY SYSTEMS CODE OR WITH A FIRE-EXTINGUISHING SYSTEM WHICH, IN THE OPINION OF THE ADMINISTRATION, GIVES EQUIVALENT PROTECTION FOR THE CARGOES CARRIED.