转速量测仪表一般可分为机械式、电气式两类。机械式有许多种,采用离心结构的较多。电气式的分为电机与电子式。由于电子技术的发展,近年来出现了数字显示的转速表,但复杂价高。在国产机车上采用机械式和电机式的较多,如显示柴油机转速,一般用机械式离心结构的“船用转速表”。它显示较准确,但只能装在柴油机上,不能遥测显示。所以, Speed ​​measuring instruments generally can be divided into mechanical, electrical two types. There are many kinds of mechanical, using more centrifugal structure. Electrical type is divided into electrical and electronic. Due to the development of electronic technology, digital display tachometer appeared in recent years, but the complex price is high. In the domestic locomotive using mechanical and motor-based more, such as the display of diesel engine speed, the general mechanical centrifugal structure of the “marine tachometer.” It shows more accurate, but can only be installed on the diesel engine, can not telemetry display. and so,