The testing methods for AC motors and DC motors are different, so this article only discusses the testing of AC motors. Due to the lack of specialized testing instruments, DC motors can only be measured using a multimeter 1. Voltage measurement:

1 Using a voltmeter: Adjust the r value of the multimeter × Set the 1k gear to the voltage range, with a range of 100-300V 2. Using a pointer voltmeter to measure resistance: Connect the rx terminal of the pointer multimeter to the component to be measured in the circuit, and connect the red pen to the u of the instrument × 1k gear up; The black pen is connected to the red of the instrument panel × 1k gear up; Then press the "+" key once to display the value

3. Use the dg5 or dm6 gear of the digital multimeter for measurement:

(1) Measure the r of the digital multimeter × Set 10k or dm15 to the resistance position

(2) Range selection 10k ω 。

(3) Press the "+" key When the displayed value is the same as the nominal value, it is considered normal When the displayed value is 0, it indicates that the resistance value is infinite 2. Measurement of current value:

1 Using an ammeter:

(1) Connect the ammeter in series to any node in the circuit to be tested (2) Turn the knob of the ammeter to the corresponding scale position on the dial and fix it in place (3) Press and hold the buttons at both ends until the indicator light turns off

3. Power measurement:

1. Use a clamp power meter 2. Use the p-p switch of the oscilloscope 4. Measurement of speed and speed difference

1. Measurement of DC motor speed:

1) The DC motor speed can be determined using the frequency characteristic curve method 2) Rotate the rotor under rated load to reach the rated speed Immediately cut off the load after measuring the rotor speed 4) Then connect the load and repeat the above operation If the results of two experiments are the same, it is considered constant