Specifications

99
When gear boxes and change/reduction gears lubricated with oil are used in power transmission systems, continuous low
speed operation decreases the benefits of oil lubrication function. Also, operation at more than 60 Hz may result in noise,
reduced life, etc.
Notes
Power Transmission Mechanism（Gear Reduction, Belt, Chain, etc.）
For applications requiring repetitive loads (such as cranes, elevators, presses, washing machines), if a high current exceeding
125% of the inverter rated current repeatedly applied, the IGBT in the inverter is subject to heat stress and will result in a
shortened life. If so, reduce the size of the load, lengthen the acceleration/deceleration time, or increase the frame size of the
inverter so that the peak current for repetitive operation is reduced to less than 125% of the inverter's rated current. When
performing a trial operation with repetitive loads, make sure that the peak repetitive current is less than 125% of the inverter's
rated current, and make the proper adjustments if necessary. As a guideline, the number of starts and stops is approximately
four million times with the function for carrier frequency reduction is enabled (factory setting =1: L8-38) and a peak current of
125% (two million starts and stops at 150%). When using Flux Vector Control, the drive is rated at two million start and stop
cycles with a peak current of 125% and the carrier frequency kept at its default setting (one million stop and start cycles with a
peak current of 150%).
Also, if low noise is not required, reduce the inverter carrier frequency to 2kHz to reduce the heat stress.
Especially for use with cranes where rapid starts and stops are needed for inching, secure the motor torque and reduce inverter
current by following these recommendations when selecting an inverter.
●For motors of 75 kW or less
The inverter capacity must be less than 125% of the peak current. Or, increase the inverter capacity to one or more frames
greater than the motor capacity.
●For motors exceeding 75 kW or motor cable length of 100 m or longer
The inverter capacity must be less than 125% of the peak current with the flux vector-control inverter. Or, increase inverter
capacity to two or more frames greater than the motor capacity.
Additional technical notes on elevator applications, and inverters specially designed for use with elevators and cranes are
available. For details, contact your Yaskawa representative.
Notes for repetitive load applications