4-2 Function Mode Note 1: Make sure that the carrier frequency (b083) is not lower than 2.1 kHz. If the carrier frequency is lower than 2.1 Hz, the Inverter does not operate normally. Note 2: To use lower rank motor size than the Inverter, set a torque limit value (b041 to b044), while keeping the value α , calculated with the following formula, at 200% or lower. Otherwise, the motor may burn out. α = Torque limit set value Ч (Inverter capacity) / (Motor capacity) (Example) If the Inverter capacity is 0.75 kW and the motor capacity is 0.4 kW, the torque limit set value for α = 200%, calculated with the above formula, is as follows:
Torque limit set value (b041 to b044) = α Ч (Motor capacity) / (Inverter capacity) = 200% x (0.4 kW)/(0.75 kW) = 106% 0-Hz Sensorless Vector Control •This function enables high-torque operation in the 0-Hz range (0- to 3-Hz frequency reference). This control method is particularly suitable for applications such as an elevating system, which requires sufficient torque in a low-frequency range at startup (e.g. crane, hoist). •To use this function, set V/f characteristics selection A044/A244 to "04". •To use this function, make sure that the motor parameter settings are suitable for your motor.
(Refer to "Motor Parameter Selection" (page 4-110).) •The parameters for 0-Hz SLV control are as follows: •In 0-Hz limit H060/H260, you can set a current value used for constant current control in the 0- Hz range (generally, 3.0 Hz or lower). This parameter is expressed as a ratio of the output current to the Inverter's rated current. •In 0-Hz SLV startup boost amount H061/H261, you can set a current boost amount at startup in the 0-Hz range. A current value expressed as a ratio to the Inverter's rated current is added to the current value set in H060/H260 at startup only. 4 Functions •Note the following before use: •Select an Inverter with one rank higher in capacity than the motor's.
•Sufficient characteristics may not be obtained if you select a motor size two or more ranks lower than the maximum applicable motor size. •In the 0-Hz sensorless control mode, the digital command board (3GAX-DI01) cannot be used. 4-112 Parameter No. Function name Data Default setting Unit H060/H260 Limit at 0 Hz 0.0 to 100.0: Current limit in low frequency range 100.0 % H061/H261 Boost amount at SLV startup, 0 Hz 0. to 50.: Current boost amount at startup 50. %