0.00 ESR reading on a capacitor

[Fuzzy Fix]

Howdy all I have a 90uF Capacitor 200/275 VRMS and measured the ESR . Reading says 00.3 Ohms and about 1/2 a second later 00,0 and says low ESR (Really No Kidding).
I have checked it on the multimeter and reading is 94.7uF well within soec as ir has a 25% tolerance on it.
Can anyone advise me is this capacitor likely to fail in the near future or still good to use.

[CapLeaker]

You can't trust a small ESR tester on higher voltage capacitors as they don't show leakage.

[stj]

what tester was it?

[redwire]

MS22 series is motor start, aluminum electrolytic. Duty cycle small at 1.67%
I think an ESR tester needs high pulse-current to measure decently, a flea fart tester will not measure accurately. Even then, there are no ESR specs for these type of caps. Similar parts ESR 1 to 2Ω.
Motor start/run caps have a safety discharge resistor in them, typ. 32,000Ω for 220VAC rated cap. so measuring resistance it will top out at that, looks like a low value but is OK.

[stj]

if it has a discharge resistor you cant test capacitance or esr

[redwire]

Motor start/run caps have agency approvals which include the resistor. Here I think it's BS5267.
If the cap tester is dual-slope (measures both up ramp and down ramp) I think it can work despite the safety discharge resistor making it appear leaky.
ESR you need 50mA pulses I would say like the Blue ESR meter can do.
Op's cap could be dodgy chinese stuff, Aerovox website dead and it does look a little fake.

[stj]

it's not fake, just ancient
https://www.procureinc.com/manufactu..._Rifa_-_Kemet/

[redwire]

Motor capacitor made in the UK? Ends up in Australia? Next you'll be telling me the earth is round lol.
They usually dry out and capacitance value drops, so I would not replace it, check if a date code on it.

I would expect it to last if it's not in a hot location like mounted on the motor etc. and vibration also can make them fail. It really sees only seconds of use with every motor start.

OP's ESR meter seems suspect, the test leads, the battery, the zeroing etc.
If in doubt, test it using a resistor say 1Ω, see what it reads.