PA7300 Instruction Manual - TECO-Westinghouse Motor Company

(25) Speed search detection level (Cn-38)When inverter output current immediately after power recovery is larger than the setvalue of Cn-38, speed search operation is started. When inverter output current issmaller than the set value of Cn-38, the frequency is interpreted as a speedsynchronization point and acceleration or deceleration is perormed again up to aspecified frequency.(26) Speed search time (Cn-39)Set deceleration time during speed search in units of 0.1 second. Setting of 0.0second causes no speed serch.(27) Minimum baseblock time (Cn-40)On detecting momentary power loss, the inverter shuts off output and maintains thebaseblock state for a given time. Set in Cn-40 the time when residual voltage isexpected to be almost zero.When momentary power loss time is longer than the minimum baseblock time,speed search operation is started immediately after power recovery.WHEN MIN. BASEBLOCKTIME IS LONGER THANMOMENTARY POWERLOSS TIME.WHEN MIN. BASEBLOCKTIME IS SHORTER THANMOMENTARY POWERLOSS TIME.MOMETARYPOWERLOSS TIMEMIN.BASEBLOCKTIMEINVERTERBASEBLOCKTIMEMOMETARYPOWERLOSS TIMEMIN.BASEBLOCKTIMEINVERTERBASEBLOCKTIME(28) V/f speed search (Cn-41)To ensure that a fault such as OC does not occur during speed search operation, V/fmust be reduced during speed search operation, as compared with that duringnormal operation. Set V/f during speed search as follows by the set value of Cn-41:V/f during speed search = V/f at normal operation × Cn-41(29) Voltage recovery time (Cn-42)Set in Cn-42 the time between completion of speed search operation and return toV/f at normal operation. The set of voltage recovery time is set as follows:220V Class: Time required to raise voltage from 0 to 220V440V Class: Time required to raise voltage from 0 to 440V59