What is a method used to measure motor shaft speed?

A touch tachometer is a widely used method for measuring motor shaft speed due to its direct and straightforward approach. It functions by making contact with the rotating shaft and providing a digital readout of the rotational speed. This device is particularly useful in diverse mechanical settings because it measures the speed of the shaft without requiring complex setups or additional equipment.

When using a touch tachometer, the operator simply places the device against the shaft, and the inherent rotational motion generates an accurate speed reading. This makes it a practical choice for applications where quick and reliable measurements are crucial, such as routine maintenance or troubleshooting.

In contrast, other devices mentioned may not be suitable for direct measurement of motor shaft speed. A digital multimeter is primarily designed for electrical measurements (voltage, current, resistance) and does not typically measure rotational speed directly. An oscilloscope can visualize signals but requires additional setup to correlate those signals to a shaft's speed, making it less direct and more complex for this specific purpose. A laser speed meter offers a non-contact method to measure speed by reflecting a laser beam off the surface of the shaft; however, it might be less practical in settings where contact measurements can be easily taken or where the reflective surface quality is poor.