The speed of the motor is usually measured in RPM (revolutions per minute). It is one of more difficult tasks but it is one of the most important things to know about your motor. There are several ways to do it.

• A strobe light (stroboscope) may be used to measure RPM. Some strobe lights have active counters showing the flash rate.
• Optical tachometers may be used to determine spin rate, however they require something like a propeller attached to the motor which may slow it down.

But YOU really know how a measure RPM works?

Is a device designed to measure rotational or surface speed either in contact or non-contact way.

also the rpm measured are called tachometers beacuse is one of the most important think.

The RPM maximum can be 1400 RPM and the minimum 1000 RPM