UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post

Silicon · 10th Nov 2018, 2:27 pm

33 1/3 rpm may have been chosen to give a gearing ratio that was a whole number when using a synchronous motor operating at either 50Hz or 60Hz.

10th Nov 2018, 2:27 pm	#11
Silicon Nonode Join Date: Jun 2007 Location: Coulsdon, London, UK. Posts: 2,163	Re: Why both 33 and 45 ? 33 1/3 rpm may have been chosen to give a gearing ratio that was a whole number when using a synchronous motor operating at either 50Hz or 60Hz.