It is dangerous to operate a series connected motor such as a starter motor without a high load, if no load is present, the field current decreases and the motor can start to run away, often to the point of destruction!.
BTW you may wonder why the series wound motors (Universal) found in power tools etc do not fly apart is because small motors have a built in degree of regulating friction load which large motors do not.
Al
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CNC, Mechatronics Integration and Machine Design.
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E. |