I ka makahiki 1895, ua hoʻopuka ʻo German Overtone i ka mea mua ma ka honuaʻO ka drill uila DC.Hana ʻia ka pūpū i ka hao a hiki ke wili i nā puka 4mm i ka pā kila.Ma hope mai, ua ʻike ʻia kahi pahu uila uila ʻekolu-phase (50Hz), akā ʻaʻole i ʻoi aku ka wikiwiki o ka mīkini ma mua o 3000r/min.I ka makahiki 1914, ua ʻike ʻia nā mea uila e alakaʻi ʻia e nā kaʻa hoʻokahi-phase series, a ʻoi aku ka wikiwiki o ka mīkini ma mua o 10000r/min.I ka makahiki 1927, ua ʻike ʻia kahi hāmeʻa uila uila waena me kahi alapine mana o 150 a 200 Hz.ʻAʻole wale ia ka pōmaikaʻi o ka wikiwiki kiʻekiʻe o ka mīkini hana hoʻokahi-phase, akā loaʻa nō hoʻi nā pōmaikaʻi o ka maʻalahi a me ka hilinaʻi ʻekolu-phase mana frequency motor.Eia nō naʻe, pono e hoʻolako ʻia me ke alapine waena., Ua kapu ka hoohana.