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 !
You should use balancing resistors across the capacitors, assuming it's a simple series connection of electrolytic capacitors.
The appropriate resistor to use across each capacitor is
R = \$ \frac {n V_M - V_b}{0.0015C V_b}\$
R is in M ohms
n is the number of capacitors
C in uF is the capacitance of each capacitor
\$V_M\$ is the voltage allowed on each capacitor
\$V_b\$ is the total voltage across the string
If we allow 400V across each cap and total voltage will not exceed 15kV
then we have a balancing resistor value of 555K ohms.
Each one needs a power rating suitable for the highest possible voltage,
so
\$P_R = \frac {V_M^2}{R} \$ = 0.29W for this example
The balancing resistors will suck 0.54mA in this example, which is 8.1W total,
a significant power loss, so you may not be able to get full voltage from your coil.
Reference: Cornell-Dublier Aluminum Electrolytic Capacitor Application Guide
Best Answer
Make sure that the replacement part is comparable in terms of ESR (equivalent series resistance), rated ripple current and rated hours. Don't use a general-purpose cap (usually rated for 1000 hrs or less, with ripple current specified at 120Hz) instead of a high-performance cap (ripple current specified at 100kHz, ESR in milliohms)
If the original capacitor was used in a high-frequency application (i.e. a capacitor on the output of a switching regulator) putting in a part that is not suited for the task will result in a severely shortened life for the cap and the need to replace it again once it blows up.
In general, going from 25V to 35V won't cause you a problem as long as the above parameters are comparable. Once you start getting above 35V, you'll find less and less high-performance capacitors available (the majority of low ESR parts tend to be 25V or lower).