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Quick setup
4.4 IGBT Enable
In all elevator applications, an Output Contactor is installed between the AC drive
output U, V, W and the motor.
In an emergency, the Safety Line is opened due to an unsafe condition and the Output
Contactor disconnects the power from the inverter to the motor (the motor brake is
also applied at the same time). When the Output Contactor opens with current flowing
through to the motor (inverter IGBTs are active), there will be arcing in the Output
Contactor depending on the motor inductive energy. Arcing of the Output Contactor can
reduce the lifetime of the contactor and in some severe cases can damage the contacts
poles. Therefore it is recommended to electronically switch off the AC drive IGBT firing
circuits before opening the Output Contactor (milliseconds later). The AC drive IGBT
firing can be electronically switched off with the "IGBT Enable" function as shown in the
timing charts below.
CAUTION
: An Output Contactor MUST always be installed as the final safety power
cut off to the motor. The "IGBT Enable" function is NOT a substitute for an Output
Contactor, it is designed to work together with the Output Contactor.
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Figure 4-4
IGBT Enable timing diagram
