0
\$\begingroup\$

I am attempting to repair a UV lamp for curing resins and epoxies. I determined the capacitor was the problem and ordered a replacement (7C100M33R). I got the last one the site had available - and they sent me the wrong one. They sent me a 12 MFD capacitor instead of a 10 MFD.

The UV lamp has a switch, potted ballast and this capacitor, that's all of the internals. Its output goes to a 100W Sylvania mercury arc bulb.

Model of UV Lamp: Spectroline Model SB-100P (120V, 60Hz, 1.05A)

Original capacitor: 10 MFD 330 VAC 50/60 Hz (Model 7C100M33R)

Replacement capacitor: 12 MFD 330 VAC 50/60 Hz (Model 7C120M33R)

Everything I have read discusses using a larger capacitor for a motor being okay, but because this is expensive equipment, I wanted to double check that a 12 MFD capacitor wouldn't damage the ballast. I need this repaired so I'd rather not send it back and wait for a replacement, if one even exists. I'm hoping this one will work. Please advise me.

\$\endgroup\$

1 Answer 1

Reset to default
1
\$\begingroup\$

That's a difference of 20% which is rather large in this application. You could damage the ballast (by overheating) or shorten the life of the lamp.

I suggest not doing it.

\$\endgroup\$
3
  • \$\begingroup\$ P.S. if the price you paid was anything like what a brief googling yielded ($100-ish), I would be tempted to return it and sub a 10uF motor run capacitor for maybe $5-6 from a local HVAC or appliance parts shop. \$\endgroup\$
    – Spehro 'speff' Pefhany
    Commented Jul 22, 2023 at 1:32
  • \$\begingroup\$ This may be discontinued by the mfr: radwell.com/en-US/Buy/PHILIPS/ADVANCE%20BALLAST/7C100M33R -- If you are using this on 50 Hz, the 20% lower frequency may compensate for the 20% higher capacitance, especially if it actually measures on the low side of the tolerance. So in that case it would present a lower risk. \$\endgroup\$
    – PStechPaul
    Commented Jul 22, 2023 at 1:34
  • 1
    \$\begingroup\$ Yes, Radwell is who I sourced it from. The UV lamp is old but we don’t have the funds for a new one (thousands of dollars). So I’ll take a $100 part that I know is valid for the machine than something else. But if I absolutely can’t find one with the right specs, I’ll try a run motor cap. \$\endgroup\$
    – gban
    Commented Jul 22, 2023 at 20:12

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.