主机转速表 meaning in English

main engine revolution indicator
main engine revolution speedometer

Main engine revolution speedometer
主机转速表
On the bridge main engine instrument board , there is main engine cooling water thermometer , lub oil pressure gauge , main engine revolution indicator , main engine emergency shutdown pushbutton , and there is audible and visual alarm device for main engine lub oil low pressure , cooling water high temperature , gear box lub oil low working pressure
本船驾驶室主机仪表板设有主机冷却水温表、滑油压力表、主机转速表、主机应急停车按钮，并具有主机滑油压力低、冷却水高温、齿轮箱滑油工作压力低的声光报警装置。