Vol. 3, Issue 3 (2019)
An experimental research on the feasibility of shaft voltage as a potential and economic low power source
Author(s): Parantap Nandi
Abstract: Electric motors of low wattage rating while in operation have an e.m.f between the rotating shaft and the ground pin of the wall socket. The value of this voltage, better known as ‘shaft voltage’ ranges from a few mV to as large as 100V depending on a variety of factors. In A.C motors the shaft voltage is alternating in nature while in D.C motors this is either negative or positive relative to ground though A.C components of the order of mV are frequently present. Shaft voltages of high magnitudes are considered detrimental and techniques are adopted to minimize it. A voltage of the order 5V is not infrequent. Instead of minimizing, it may be used to feed loads not requiring high power. Indeed this is the case and the load current in no way affects the current drawn by the motor whether in magnitude or waveform. In this paper nature of ‘shaft voltage’ and techniques for harnessing it has been elaborated.