问题 单项选择题

有一台6kW的三相异步电动机,其额定运行转速为1480r/min,额定电压为380V,全压启动转矩是额定运行转矩的1.2倍,现采用Y-△启动以降低其启动电流,此时的启动转矩为()。

A.15.49N·m

B.26.82N·m

C.38.7N·m

D.46.44N·m

答案

参考答案:A

解析:

阅读理解

A. You and Me, Baby


Reading level: Baby-Grade 1
Hardcover: 40 pages
Language: English
List Price: $15.95
Price: $12.44 & eligible(有资格的) for FREE Super Saver Shipping on orders over $25.
You Save: $3.51 (22%)
Availability: In Stock. Ships from and sold by Amazon. Gift-wrap available.
Only 4 left in stock--order soon (more on the way). Want it delivered Thursday, September 27.
B. Ruff! Ruff! Where's Scruff?


Reading level: Baby-Preschool
Hardcover: 16 pages
Language: English
Price: $11.16 & eligible for FREE Super Saver Shipping on orders over $25.
Availability: In Stock. Sold by Amazon. Gift-wrap available.
Want it delivered Thursday, September 2.
Book Description: It’s bath time for Scruff. But does anyone know where he’s hiding? Have the cows seen him? Moo-no! How about the pigs? Oink-no! Looking for that dog is just too tough! But not for toddlers. If they look carefully, they’ll find Scruff hiding on every pop-up page!
C. The Giving Tree


Reading level: Ages 4-8
Hardcover: 64 pages
Language: English
Price: $11.55
Availability: Sold all year round and choose One-Day Shipping at checkout.
Book Description: Once there was a tree...and she loved a little boy. Every day the boy would come to the tree to eat her apples, swing from her branches, or slide down her trunk...and the tree was happy.
D. Where the Wild Things Are

 
Reading level: Ages 6-10
Hardcover Comic: 62 pages
Language: English
List Price: $16.95
Price: $11.53 & eligible for FREE Super Saver Shipping on orders over $25.
You Save: $5.42 (32%)
Availability: In Stock. Ships from and sold by Amazon. Gift-wrap available. Want it delivered Thursday, September 12. Order it at once, and choose One-Day Shipping at checkout.
60. Little Tom who likes to read picture books with a hide-and-seek adventure will be likely to buy _____.
A. Ruff! Ruff! Where’s Scruff?            B. You and Me, Baby    
C. The Giving Tree                      D. Where the Wild Things Are
61. How much will you pay if you order three books named Where the Wild Things Are?
A. $16.26                        B$ 75                        C. $ 50.58               D. $34.59
62. Which of the following is not true according to the passage?
A. The language of four kinds of books is English.
B. Four kinds of books are available at present.
C. The cover of four kinds of books is hardcover.
D. The reading level of four kinds of books are the same.
63. Where would this advertisement probably appear?
A. In a children’s story-book              B. On the front page of a newspaper.
C. On the Internet.                     D. In a popular magazine.
选择题