Terms and Definitions
The following definitions apply to power capacitors according to IEC 61071.
Rated capacitance CR
Nominal value of the capacitance at 20 °C and measuring frequency range of 50 to 120 Hz.
Rated DC voltage VR
Maximum operating peak voltage of either polarity but of a non-reversing type wave form, for which the capacitor has been designed, for continuous operation.
Ripple voltage Vr
Peak-to-peak alternating component of the unidirectional voltage.
Maximum surge voltage Vs
Peak voltage induced by a switching or any other disturbance of the system which is allowed for a limited number of times and duration.
- Maximum duration: 50 ms / pulse
- Maximum number of occurrences: 1000 (during load)
Insulation voltage Vi
Rms rated value of the insulation voltage of capacitive elements and terminals to case or earth. When it is not specified in the product data sheet, the insulation voltage is at least:
Maximum rate of voltage rise (dv/dt)max
Maximum permissible repetitive rate of voltage rise of the operational voltage.
Maximum current Imax
Maximum rms current for continuous operation.
Maximum peak current Îpk
Maximum permissible repetitive current amplitude during continuous operation.
Maximum peak current (Îpk) and maximum rate of voltage rise (dV/dt)max on a capacitor are related as follows:
Îpk = C · (dv/dt)max
Maximum surge current Î s
Admissible peak current induced by a switching or any other disturbance of the system which is allowed for a limited number of times (1000 times) and duration (50 ms / pulse).
Îs = C · (dv/dt)s
Ambient temperature ΘA
Temperature of the surrounding air, measured at 10 cm distance and 2/3 of the case height of the capacitor.
Lowest operating temperature Θmin
Lowest permitted ambient temperature at which a capacitor may be energized.
Maximum operating temperature Θmax
Highest permitted ambient temperature at which a capacitor may be energized.
Hot-spot temperature Θhs
Temperature zone inside of the capacitor at hottest spot.
Temperature hot-spot / ambient ΔΘ
Temperature difference between the hottest spot in the capacitor Θhs and the ambient temperature ΘA.
Tangent of the loss angle of the dielectric tan δ0
The loss factor of the dielectric (polypropylene) represents the portion of the losses in the process of
polarization/depolarization of the dielectric. It is considered constant in the whole operational
frequency range of the capacitor.
Tangent of the loss angle of a capacitor tan δ
Ratio between the equivalent series resistance and the capacitive reactance of a capacitor at a
specified sinusoidal alternating voltage, frequency and temperature.
Series resistance Rs
The sum of all Ohmic resistances occurring inside the capacitor. It is largely independent of frequency.
Thermal resistance Rth
The thermal resistance indicates by how many degrees the capacitor temperature at the hot spot rises
in relation to the dissipation losses.
Maximum power loss Pmax
Maximum permissible power dissipation for the capacitor’s operation.
Pmax = th R
hs A Θ − Θ= th R ΔΘ
Self inductance Lself
The sum of all inductive elements which are contained in a capacitor.
Resonance frequency fr
The lowest frequency at which the impedance of the capacitor becomes minimum.
fr =self N
Metallized polypropylene film capacitors – Plastic case for general purpose applications
Lateral brackets for fixing are standard for all types.
Male M8 terminals