capacitor
Here are a handful of capacitors, that I just salvaged from a burned out a 230VAC to 12VAC power supply. O those, I am familiar only with the electrolytics and how to read their capacitance, maximum voltage, polarity and maximum opperationg temperature.
What are the other cap types shown into the picture and how to read their parameters? Optionally, in what applications is each of those types preferable?
As ever, a full circuit diagram would be invaluable - even if to show that there is nothing much more present than has been stated.
VAC = 220V so Vpeak = 220*1.414 =~ 310V. 180V DC/310 =~ 0.58 This is the sine of thge angle when the rectifiers start (or end ) conducting + 35 degrees. For 35/90 of the cycle the voltage in is below Vdc so the cap MUST provide the motor current. If you do not have any energy storage in inductors then the cap is seeing a ripple current of in the order of the motor current and peak currents will very likely be higher (depending on transformer and wiring resistsance and more.)
As dissipation will be in the order of proportional to current squared you probably have about 10 x rated dissiation due to excess ripple current.
Nichicon are a well respected brand. Chances are the actual ripple current capacity on a genuine Nichicon meets or exceeds specifications. But it is unlikely to exceed it by enough to save you here IF the circuit is as it seems. It is possible that the cap is a counterfeit. This definitely happens and Nichicon are a well enough known brand that people MAY counterfeit them, although I have no specific knowledge of this happening in this case.
UUCAP I know not.
It is not unusual for little known Asian components to not come close to spec sheet claims.
In this case it appears that they exceed the specs handsomely !!!!
I'd not complain!
But do look at the actual ripple current.
A small sense resistor in the cap ground lead will allow a scope to be used with due care (or in the "hot" side with an isolation device AND if you know what you are doing. Or a Hall clamp / proximity meter or ... .
Note that cap lifetime ~+ Rated hours x 2 ^ [(Trated-Trun) / 10 ]
It is usual to run a cap at WELL below rated temperature.
30C below = 2 ^ (30/10) = 8 x rated lifetime.
So a 2000 hour rated cap would last about 2000 x 8 = 16000 hours ~= 2 years.
The larger margin the better.
Note that an Al electrolytic cap with NO applied voltage, held at high temperature will die faster than when voltage is applied !
One pretty simple reason is that the tolerance on Y5V tends to be much flakier numerically than X5R or X7R. Typically -20% + 80%
A less obvious and possibly more profound reason is that the change in capacitance versus temperature is very poor on Y5V. Typically at low temperatures and high temperatures the capacitance might halve in value.
DC voltage can change the capacitance of most capacitors a bit but Y5V are really prone to it. Typically at full rated voltage the capacitance might be a fraction of what it is when low voltages are present.
Just open this data sheet and look at the first few graphs. See also this: -
Best Answer
Yellow and Red: Film capacitors. Red: Without safety approval. Yellow: With safety approval. (Colors: Just in your case. It's not because of the colors, it's because of the X... markings! Any type may be made in any color!) Depending on the conductor (real film or metallic layer) and dielectric, they feature (very) low ESR and (very) low dissipation factor. Good for switching power applications whenever you need more capacitance than ceramic capacitors can offer. You added the info that the red ones read 100nJ400, which means 100 nF; Tolerance: 5 %; 400 V. Common tolerance codes for capacitors: J = ± 5%; K = ± 10%; M = ± 20%.
Blue, from left to right: 2 x Safety-Rated Ceramic Disc Capacitors. Very low ESR, sometimes with a big tolerance and temperature coefficient, though. The third blue disc from the left appears to be a varistor, not a capacitor. It is labeled 7K471. 7K means it has a disk size of 7 mm (the disk size corresponds to the energy it can absorb) and it starts to conduct at or above "471" = 47*101 V = 470 V. Number four is 221; 1KV (no safety rating visible), meaning 22 * 101 pF = 220 pF; max. voltage 1 kV.
Black: Electrolytic Capacitors. Some bad properties, but you get an awesome C*V product per volume.
Hints on reading the values:
https://electronics.stackexchange.com/a/33454/930
Identifying Capacitors
Hints on the safety ratings: X means you may use these between live and neutral (L and N). This is a critical application because a small leakage path will continuously be fed from the lines and fires may result. I have had one of these fail in a HP function generator last year and the room smelled toxic for weeks, even though I washed out all the stuff left by the smoldering decomposition of the cap - and luckily the design of the cap was of the self-extinguishing type. Y means you may use the caps between L or N and PE. Critical because fires may result for the reason just explained, and because an insulation failure may result in L being connected to the housing (PE). The number behind the X or Y shows the class (good or better). Datasheets will tell you more. Search for X1, X2, Y1 or Y2 and EMI capacitor. EMI because these capacitors are usually used in input filters, often before the fuse, and thus exposed directly the the mains terminals feeding your device.