Pennwood Wrong Wattage for Pennwood numechron motor

[78Rus]

Hi! I have two motors (pennwood numechron) for desktop clock. Wattage indicated as 3,7 W. But when connect ammeter is obtained 50mA, which corresponds to 55W. Why so? Thanks!

 

[praezis]

Hi! I have two motors (pennwood numechron) for desktop clock. Wattage indicated as 3,7 W. But when connect ammeter is obtained 50mA, which corresponds to 55W. Why so? Thanks!

...because 120V x 50mA gives 6W, no 55W
...because with inductive loads there is a phase shift between AC voltage and current, and then V x A is different from Watt.
...because a running motor generates his EMF voltage which is subtracted from his supply voltage.

Regards,
Frank