sizing of "run capacitor" for table saw motor needed
I have an old Sears Craftsman table saw, with a 3450 rpm motor. The capacitor just failed, and I could easily replace it with one from Grainger, if only I knew how many microfarads to select (i.e., capacitance). The old one is an oil-filled rectangular can, and the markings are illegible.
I have read things here and there, with one person in this forum saying that it's OK to select an overly-high microfarad value. I am deeply suspicious of that comment, though I cannot speak with authority.
I believe the value is somewhere between 5 uF and 70 uF. The capacitor is used to impart a phase shift to a secondary winding in this AC induction motor, and the amount of that shift is critical towards maintaining efficient operation and longevity in the motor. On the other hand, the motor runs only briefly, so I suppose I could err without burning the motor windings.
I'll probably buy several capacitors, and use a trial-and-error method. Of course, I would appreciate any experienced advice, on this matter.
More about the motor; it's a nice heavy motor from the 1950s and I have been using it for about a week. It was given to me 10 years ago, and I only recently resurrected my old saw, which needed a motor replacement. Suddenly, it stopped working. The motor did not burn.
Motor's original manufacturer: Emerson Electric
"Sears & Robuck" on the motor's plate.. . type CR260K20 Model 157167. 3/4 HP. 3450 RPM. 115 VAC, 9.3Amps, 60 cycle.
Dimensions of the old capacitor, 4,88" long x 3.15" wide x 1" thick.