Made from 63V Capacitors OEM Cap Banks used on ZTW 150HV.  It is generally reported that capacitor failures can be attributed to:1) Heating, causing a capacitor to swell and explode.2) Drying of the liquid electrolytic inside from various causes, such as defects, leaking and even cleaning.3) Capacitors re-form over time to meet a usual and expected voltage. Surges that are not normal can cause sudden failure.4) The older they get the greater the incidence of failure.5)High-current motor setup will tend to kill the caps quickly (because of the large voltage changes).WARNING: If any capacitors seem to bulge, start to deform, leak or pop, stop using them IMMEDIATELY!!! If Capacitors fail they can explode and cause injury.