Bulletin No. 5600PD9601
July 1996
Oxford, OH, USA
裙子 英语Product Data Bulletin纳尼亚传奇2片尾曲
MYLAR ® BUS BAR INSULATION—A THIRTY YEAR TRACK RECORD
For more than 30 years, Square D has ud Mylar ® to insulate bus bars in I-Line ®and I-Line II Busway. The purpo of this paper is to provide information demonstrating that Mylar is both a proven and reliable insulation system.
QUESTIONS AND ANSWERS
What is Mylar ®?
Mylar is a polyester film made from polyethylene terephthalate, the polymer formed by the condensation reaction of ethylene glycol and terephthalic acid.Mylar has an average dielectric strength
of 7,000 volts for 1 mil film, a tensile strength of 23,000 psi, and an excellent resistance to most chemicals and
moisture. Mylar also remains flexible throughout temperature extremes from –60° to 150°C and does not become brittle with age.
Does Mylar ® meet To meet to Underwriters Laboratory (UL) requirements, UL Listed busways UL requirements?
cannot exceed a total operating temperature of 95°C in an ambient temperature of 40°C at full load. This requirement applies to the complete busway system, not just a single busway component. At loads up to and including the full load rating and at 40°C ambient temperature, I-Line and I-Line II Busway will not exceed a total operating temperature of 95°C. Actual supplier testing (DuPont #EL-63-2)has proven Mylar to have a conrvative Class B, 130°C thermal rating, which is 35°C above the approved operating temperature of UL Listed busways.What about reliability?
I-Line and I-Line II bus bars are insulated with two layers of 7.5 mil Mylar. Once asmbled, every busway length and fitting must pass a 7,000Vdc (4,950Vac)hi-potential test before shipment from the factory. The factory test is conducted at eight times greater than the maximum operating voltage to
become的意思ensure the highest quality insulation with every ction of busway delivered.
Mylar has many electrical applications in addition to insulating bus bars. Many manufacturers also u Mylar as insulation in transformers and electric motors.In fact, one of the largest electric motor manufacturers in the United States has ud Mylar as a stand-alone insulator in Class B motors for over 35 years.
Laminates containing Mylar are commonly ud in Class F motors with ratings of 115°C and higher.
ELECTRICAL PROPERTIES With an excellent balance of chemical, thermal, and physical properties, the OF MYLAR ®
electrical properties of Mylar offer unique design capabilities to the electrical industry.
Film Thickness
The average dielectric strength for 1 mil film is 7,000 volts. For 7.5 mil film, the dielectric strength is approximately 2,700 volts/mil for an excellent dielectric strength of 20,250 volts. I-Line and I-Line II Busway u two layers of 7.5 mil film for a total insulation thickness of 15 mil. As with most materials, the ac dielectric strength of Mylar film in volts/mil decreas as film thickness increas. T
his is illustrated in Figure 1, page 2. After being tested at a 500volts/cond rate of ri, corona occurs within conds and the film begins to melt before the actual breakdown occurs.
Bulletin No. 5600PD9601July 1996
Mylar ® Bus Bar Insulation—A Thirty Year Track Record
2
Figure 2: Dielectric strength vs. temperature
Figure 1: Dielectric strength vs. thickness
Insulation Resistance
Another outstanding property of Mylar is its high insulation resistance over a wide temperature range. As shown in Figure 2, the dielectric strength remains constant over a temperature range from 25°C up to 150°C.
课堂游戏
Bulletin No. 5600PD9601 Mylar® Bus Bar Insulation—A Thirty Year Track Record
July 1996
Bulletin No. 5600PD9601July 1996大桥英语
Mylar ® Bus Bar Insulation—A Thirty Year Track Record
PHYSICAL AND THERMAL Mylar polyester film retains good physical properties over a wide temperature PROPERTIES OF MYLAR ®
range from –60° to 150°C. Its shear strength is significantly higher than published data for other polymeric insulating materials. Mylar is also resistant to electrical creepage.
Shear Strength
Shear strength was measured by a punch-type test according to ASTM D-732.This measurement is reported in pounds of force required to shear divided by the product of the circumference and the thickness. The tests showed that 5and 10 mil Mylar films have shear strengths of 15.0 (21.5) and 13.6 (19.5) kg/mm 2(kpsi), respectively.
Heat Aging and Service Life
The film manufacturer’s maximum rvice temperature usually recommended for Mylar polyester fil
m is 150°C. UL Listed busways are designed not to exceed a total operating temperature of 95°C. Where extensive exposure, vere
environmental conditions, or unusual physical requirements such as vere flexing are involved, reducing the rvice life of Mylar may be necessary.
Becau the Mylar in I-Line and I-Line II Busway is totally enclod within the housing, the Mylar is protected against extensive exposure, vere
environmental conditions, and flexing. As a result of this protection and when subjected to normal operating conditions, long life can be expected.
CHEMICAL PROPERTIES Mylar polyester film exhibits good resistance to the action of many chemical OF MYLAR ®
reagents, solvents, varnishes, and other contaminants and is virtually
impermeable to the liquid pha of most chemicals and reagents. Oils and greas such as penetrating oil, lard, cottoned oil, and motor oil will not
escape的用法penetrate through 1mil film even after two months of constant exposure at room temperature. Mylar is relatively innsitive to moisture absorption, absorbing less than 0.8% moisture when totally immerd in water over a 24-hour period (ASTM D-570-63).
itouch是什么意思SUMMARY
Many types of bus bar insulation systems can exceed the maximum allowable operating temperature as required by UL. It is important to understand that UL Listed busways are designed not to exceed a total operating temperature of 95°C, which falls into Class A limits . Thus, high quality busway designs, like I-Line and I-Line II Busway, will never reach operating temperatures of 130°C under normal operating conditions. Unlike our competitors, Square D us
comprehensionfull-size bus bars in I-Line and I-Line II Busway. Full-size bus bars contribute to cooler operation of the busway system, lower voltage drop, and higher electrical efficiency. This equates to a lower operating cost and long life .
Today, I-Line and I-Line II Busway installations are in operation throughout the world, dating back to the early 1960s. Test data for new insulation systems is generated in laboratory conditions. Historical data generated from actual
applications is the most relevant and valuable data available. With more than 30years of both laboratory and historical data along with proven performance,Square D Busway with Mylar insulation has proven reliability in the industry.
Source: DuPont Films Enterpri
I-LINE, SQUARE D, and are Registered Trademarks of Square D Company.Mylar is a Registered Trademark of E. I. DuPont.
© 1996 Square D, all rights rerved. This bulletin may not be copied in whole or in part, or
transferred to any other media, without the written permission of Square D Company.
demo什么意思Square D Company白痴英语
5735 College Corner Road Oxford, OH, 45056 USA
