running capacitor size

[andre14]

Hi guys.

I'm trying to proper size a tun capacitor for a tbr4a031cdm motor. It's mounted in a closed enclosure in a small reverse cycle ducted system (used for heating and cooling). The specs are: single-phase, 240v, 315w, 2.6 FLA.

Double Shaft Fan Motor 315W 4P 240V PSC FR48 3 speed vented, resilient cradle

Techtop Double Shaft Fan Motor Product Code: TKR4A031CDM Replaces Below Motors: Fasco 8061S109-01 / 8061S109-04 / 8061S109-08 / 808555NVA-A16 CMG CT85-55031V-C01 / CT85-55031V-C02 Royce Cross RCT85-3154DS-ODP-C02 Kulthorn HF2J4702K Download PDF Drawing

www.electricmotor.com.au

the manufacturer recomends a 4 uF /440. I ran one for a year and a half and today I found it all melted and almost disintegrated. was it just a bad one?

as a point of discussion, chat gpt thinks that I should run a 35 uF

Thank you.

 

[brianmoooore]

I think I'd trust the manufacturer's data somewhat more than chat gpt, going by my experiences of technical stuff from AI so far.
Did you use a capacitor rated for continuous use, rather than intermittent duty?

 

[andre14]

I think I'd trust the manufacturer's data somewhat more than chat gpt, going by my experiences of technical stuff from AI so far.
Did you use a capacitor rated for continuous use, rather than intermittent duty?

Absolutely. And chose one that was rated for higher temps (85deg) because I thought it would help. That’s why I’m confused seeing it fail only after a year and a half… also confused to see such a big difference between what’s calculated using various formulas vs what the manufacturer is recommending.

 

[grumpyjohn01]

My experience although not extensive is that capacitors in this application fail for a passtime...