Patent ID: 9561568
Date: 2017-02-07
CPC Classifications: B23B,B23Q,B25H

Claim:
1. A magnetic drill, comprising: a housing with a base configured to attach to a surface; an electric motor for driving a tool; a controller configured to receive an AC input signal and operable to control a drive signal to the electric motor; an electromagnet arranged in the base of the housing and powered by a DC voltage, to magnetically couple the base to the surface; a converter configured to receive the AC input signal and, independent from the controller and in the presence of the AC input signal, to output the DC voltage to the electromagnet; and an alternate power source circuit that monitors the DC voltage output by the converter and, in the absence of the DC voltage, provides an alternate DC voltage to the electromagnet, wherein the alternate power source circuit includes a battery and a detector that monitors the DC voltage output by the converter and electrically couples the battery to the electromagnet in the absence of a DC voltage output from the converter, wherein the controller determines a number of occurrences or an amount of time when the battery is energizing the electromagnet and generates a notification when the number of occurrences of the amount of time exceeds a predefined threshold.