Author Topic: A question about capacitance and capacitors  (Read 880 times)

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Offline CarlspTopic starter

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A question about capacitance and capacitors
« on: March 20, 2019, 05:22:22 pm »
Hello everyone.

I am fixing a pet dryer, a big hair dryer for pets. The main capacitor on the controller board has gone bad. It is a 2.0 uF MPX X2 Suppression Film Capacitor. My question is, is there a big difference between a General Film Capacitor and a Suppression Film Capacitor? The reason I am asking is that I can get a 2.0 uF General Film Capacitor or a 2.2 uF Suppression Film Capacitor and I am not sure which one to use. Should I use the 2.2 uF Suppression cap as the original is a suppression cap or should I use the General Film Cap because it is the correct value? Any suggestions or info would be greatly appreciated. Thanks.
 

Online Gyro

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Re: A question about capacitance and capacitors
« Reply #1 on: March 20, 2019, 05:30:08 pm »
Hi, For an 'across the mains' suppression application, it is a safety requirement that you use a suitable X2 (or X1) safety certified part. I don't think 2.2uF is too big a difference.

EDIT: Wait, is this a capacitive dropper resistor for the controller electronics? If so, it is a little more important to be close to the correct value. 2.2uF is probably still ok. You didn't mention the voltage rating and dielectric of the 2uF one you found.
« Last Edit: March 20, 2019, 05:34:58 pm by Gyro »
Best Regards, Chris
 
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Offline DannyTheGhost

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Re: A question about capacitance and capacitors
« Reply #2 on: March 20, 2019, 06:23:41 pm »
When capacitor fails - it gets shorted or just losing its 'capacitive' behaviour. When capacitor, placed between mains, fails - what you would prefer - shorting mains or second variant? This is what X1/X2 class means - it is designed for supressing EMI surges and when it fails - it won't short mains and make blackout in your house
 
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Offline Benta

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Re: A question about capacitance and capacitors
« Reply #3 on: March 20, 2019, 07:39:06 pm »
The "X2" specification is key, as well as working voltage (and value). Do not compromise here, but get the right part.
 
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