Control Work in English by the student ______________(фамилия, имя), group ЭП-21, 2020 year.
- Прочтите текст и переведите письменно первый абзац:
Prior Use of Vegetable Oils in Capacitors
Capacitors were the only type of electrical equipment seriously considered for the use of vegetable oils. Clark, for example, mentions castor and cotton seed oils for use in capacitors (with cellulose insulation) as early as 1962. The higher dielectric constants of these fluids provide a better match with cellulose than mineral oil. In 1971, Indian researchers reported testing of coconut oil and hydrogenated castor and groundnut oils for electrical use. Later on, in 1974, these authors reported their work on processed castor and cottonseed oils and noted that castor oil was the better choice for capacitors. Further technical papers appeared in 1979 and 1983 by other Indian researchers. A U.S. pattern issued in 1985 describes possible use of soybean oil with additives in capacitors. Interest in castor oil was shown by Brazilian researchers, who reported their work in a CIGRE paper in 1987. Castor oil is mainly (80 percent) a hydroxyl-acid ester, unlike other vegetable oils, which are fatty acid esters. It is more viscous than most vegetable oils and has a higher dielectric constant than most vegetable oils (4.7 versus 3.2).
The above-referenced papers reveal that castor oil, along with polypropylene films in power capacitors, was seriously considered. Yet, synthetic aromatic hydrocarbons are still the fluid of choice for power capacitors.
In the 1990s rapeseed oil became the center of interest, as shown by technical papers published in 1995. Rapeseed oil, while not edible, was available in some countries and needed commercial exploitation.
- 2. Дайте полный письменный ответ на вопросы по тексту:
- Were capacitors the only type of electrical equipment?
- Who mentioned castor and cotton seed oils for use in capacitors in 1962?
- The higher dielectric constants of castor and cotton seed oils provide a better match with cellulose than mineral oil, don’t they?
- What did Brazilian researchers report about castor oil in their work in a CIGRE paper in 1987?
- Which oil needed commercial exploitation?
- 3. Запишите выражения, переведите письменно:
Electrical equipment, vegetable oils, castor and cotton seed oils, capacitors, cellulose insulation, the higher dielectric constants, for electrical use, a hydroxyl-acid ester, fatty acid esters, more viscous, a higher dielectric constant, polypropylene films, in power capacitors, synthetic aromatic hydrocarbons, was available, to need commercial exploitation.
Контрольную работу необходимо выполнить до 09.04.2020 и отправить на почту преподавателя: oskibit17@mail.ru