Omron 3G3RX Series, User Manual

Page: 223 / 442

4-114
4-2 Function Mode
4
Functions
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 × (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
×
(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 4-112).)
• 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.
• 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.
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. %