I wonder if this is the "resistor" to which you are alluding:
http://www.singermachines.co.uk/sewingmachineparts/foot-controls/capacitor.htm
For a simple 275V capacitor it seems well over-priced but I can't make out the capacitance value to offer you an electronics industry equivalent.
275V is an absolute minimum, IMHO. If you can get and fit a 350 or 400 V rated item, so well and good
XXX
June 2016