计算题:有S分度的热电偶测温系统如图所示。试问此动圈仪表的机械零位应调在多少度上?当冷端补偿盒的电源开路(失电)时,仪表指示为多少?电源极性接反时,仪表指示又为多少?
正确答案:
(1)热电偶冷端在40℃,但补偿盒工作温度偏离了20℃,会产生补偿电动势,故有
即仪表机械零位应调在补偿盒设计平衡点温度20℃上。
(2)当补偿盒电源开路,冷端补偿盒失去补偿作用时
(3)当补偿盒电源接反,补偿器不但不补偿,反而反补偿,故
![](https://img.274949.com/Images/2020-03/24/0ok6d8x0.jpg)
(2)当补偿盒电源开路,冷端补偿盒失去补偿作用时
![](https://img.274949.com/Images/2020-03/24/r8shwrny.jpg)
![](https://img.274949.com/Images/2020-03/24/xouxyise.jpg)
答案解析:有
![](/editor/images/201705/qrcode_for_gh_573e2a458573_258.jpg)
微信扫一扫手机做题