搜题请搜索小程序“爱下问搜题”
问题 问答题 简答题

电动机转速公式？改变电动机转速的方法？

答案

参考答案：

电动机转速公式n=（1-s）n。=（1-s）60f1/p，改变电动机的转速有三种方法：改变电源频率f1、改变磁极对数p、改变转差率s。

完形填空
配对阅读：请阅读以下左栏 5个人的情况描述和右栏电器产品的七条信息简介，请为这5个人选择最适合信息进行配对，并将答卷上对应题目所选的选项涂黑。
小题1:Bob is a middle school student. But he is often late for school. He needs to buy something to wake him up in the morning.
小题2:Tom always gets sick because he doesn’t have time for sports. He wants to ride a bicycle to work instead of driving a car.
小题3:It’s cold these days. Mr. White’s father isn’t in good health and he would like to buy something to make the house warm.
小题4:Helen is a housewife. Because she was too busy , she wants to buy a machine to wash the dishes after meals.
小题5:John is a businessman. He wants to travel to Europe for a week. He wants to send and receive e-mails from his customers顾客during his trip.
A．Air-conditioner . We have many kinds of air-conditioners made in different companies . Welcome to choose the one you like and you can feel warm even in cold winter days .
B．TCL 1778 .If you travel to another place, you don’t need to take a camera. You can use this mobile phone to take photos. You can enjoy the beautiful music on it, too .
C．Dish-washing Machine. This is the latest invention nowadays. It can wash and dry all kinds of dishes .It can help people save a lot of time .
D．Clocks .Do you often get in trouble in getting up late in cold winter mornings ? This clock can help you solve this problem . The only thing you need to do is to set the time you want to get up .
E. Watches. This kind of watch looks really fashionable. It is made in Switzerland. It will tell you the time exactly wherever you go .
F. Samsung Note Ⅱ .Have you heard of this kind of mobile phone ? You can not only use it to get on QQ, but also use it to send and receive e-mails on the Internet .
G . Bicycles .These days many young people enjoy riding bikes . It’s good for health . And it’s also help to protect the environment because it can reduce less air pollution than cars .
查看答案
单项选择题

常调压是指（ ）

A．高峰负荷时，将中枢点电压调高；低谷负荷时，将中枢点电压调低

B．高峰负荷时，将中枢点电压调低；低谷负荷时，将中枢点电压调高

C．高峰负荷、低谷负荷时，中枢点电压为一接近不变的值

D．高峰负荷时，电压调高，低谷负荷时，电压也调高
查看答案