Terms And Definitions - WEG CFW-11 User Manual

General Instructions

2.2 TERMS AND DEFINITIONS

Normal Duty Cycle (ND): inverter duty cycle that defines the maximum continuous operation current (I
and the overload current (110 % for 1 minute). The ND cycle is selected by setting P0298 (Application) = 0
(Normal Duty (ND)). This duty cycle shall be used for the operation of motors that are not subjected to high
torque loads (with respect to the motor rated torque) during its operation, starting, acceleration, or deceleration.
I : inverter rated current for use with the normal duty (ND = Normal Duty).
nom-ND
Overload: 1.1 x I
Heavy Duty Cycle (HD): the duty cycle that defines the steady state current value I
2
150 % during 1 minute. It is selected by programming P0298 (Application) = 1 (Heavy Duty - HD). It must be
used for driving motors that are subject in that application to high torques with respect to their rated torque,
when operating at constant speed, during start, acceleration or deceleration.
I : inverter rated current for use with the heavy duty (HD) cycle.
nom-HD
Overload: 1.5 x I
Rectifier: the input circuit of the inverters that converts the input AC voltage into DC; it is made of thyristors
and power diodes.
Pre-charge Circuit: it charges the DC Link capacitors with a limited current, thus avoiding higher current peaks
when powering the inverter.
DC Link: inverter intermediate circuit; DC voltage obtained from the rectification of the AC input voltage or
from an external power supply; feeds the output inverter bridge with IGBTs.
U, V, W Arms: set of two IGBTs of the inverter output phases U, V, and W.
IGBT: insulated Gate Bipolar Transistor; basic component of the output inverter bridge. The IGBT works as an
electronic switch in the saturated (closed switch) and cut-off (open switch) modes.
Braking IGBT: works as a switch to activate the braking resistors; it is controlled by the DC Link voltage level.
Gate Driver: circuit used to turn-on and turn-off the IGBTs.
PWM: Pulse Width Modulation; pulsed voltage that feeds the motor.
Switching Frequency: Frequency of the IGBTs switching in the inverter bridge, normally expressed in kHz.
Heatsink: metal device designed to dissipate the heat generated by the power semiconductors.
PE: Protective Earth.
MOV: Metal Oxide Varistor.
RFI Filter: Radio-Frequency Interference Filter for interference reduction in the radio-frequency range.
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/ 1 minute.
nom-ND
/ 1 minute.
nom-HD
)
nom-ND
and an overload of
nom-HD