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This is inside an Allen Wales (Model 9E) adding machine. It was manufactured in the late 30s or maybe sometime in the 40s from what I've read. There are notes from a technician scratched on the inside of the bottom cover of some maintenance done on it on 6/27/52, but only some springs and bushings were replaced, and it was cleaned/oiled.

I've unscrewed the mount holding it in place and looked around the other side and didn't see any markings other than the ones in the picture. Is there any way to identify this, or figure out a suitable replacement?

Capacitor

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    \$\begingroup\$ It does look capacitor-ish. Its two black cotton-insulated wires suggest a non-polarized capacitor rather than an electrolytic. A polarized capacitor usually has some markings to show when end is +ve: endcaps might also differ in appearance. Its large size suggests either high voltage and/or high capacitance (perhaps in the microfarad range). Perhaps paper/foil type? \$\endgroup\$
    – glen_geek
    Commented Nov 16, 2022 at 20:30
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    \$\begingroup\$ @glen_geek Yes, it's a paper capacitor. They had to be waxed because paper is hygroscopic. The paper itself, in fact, was wax impregnated. These rolled-up foil and paper units were then placed into outer cardboard tubes. The ends and leads were added and then everything was sealed with molten beeswax under pressure. \$\endgroup\$
    – jonk
    Commented Nov 16, 2022 at 21:01
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    \$\begingroup\$ Looks like the run capacitor for the motor. If it has failed, the motor will not turn and maybe hum. Might be a challenge to get a replacement in the same shape. \$\endgroup\$
    – Kartman
    Commented Nov 16, 2022 at 21:39
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    \$\begingroup\$ If it's a motor run cap, it's in the 30-50uF range. The "EY30" hints at 30uF. Related: electronics.stackexchange.com/questions/422902/… \$\endgroup\$
    – hacktastical
    Commented Nov 16, 2022 at 22:56
  • \$\begingroup\$ Would this work as a replacement? amazon.com/CBB20-Motor-Capacitor-30uf-Rigid/dp/B001ACFS54/… \$\endgroup\$
    – Mark M
    Commented Nov 17, 2022 at 17:01

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My guess is that the capacitor ("condensor" in the old days) is for spark supression at the contact points of the centrifugal speed governor on the series motor. Series motors are in 120V corded drills or blenders or vacuum cleaners. The purpose of the cap is completely different fron the start or run capacitors on an induction motor. Those capactors are 10's of microfarads and pass all the current through the winding to provide a phase shift. The ratings of the supression cap might be ~ 0.1uF @ 400V. The adding machine motor would run away at destructively high speed without the governor which opens the supply current hundred of times per second to limit the speed. Series motors have enormously high starting torque compared to induction motors. A 30uf cap could damage the motor.

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