Correctly interpreting the DC nameplate
If you have ever tried to figure out the field resistance from the information on a DC motor nameplate, you probably wonder what in the heck the manufacturer was thinking! You know Ohms Law, but the nameplate information just doesn't seem to follow it. For those accustomed to the format of the AC motor nameplate, DC nameplate information can seem confusing - even misleading. Misinterpret the field voltage/field current/rpm information, and a technician is liable to conclude that something is wrong with the motor. A customer may even question whether a repair was done correctly.