Confirming Startup Current And Reducing Carrier Frequency - YASKAWA Varispeed G7 Instruction Manual

DOWN (Forward)
HIGH/LOW
Torque compensation
signal: 0
0
Output frequency
Motor torque
0
During run 2
Holding brake operation
Fig 6.90 Torque Compensation Time Chart (Lowering)
1. For either increasing or decreasing torque, externally maintain the torque compensation signals during
operation to prevent them from fluctuating. Fluctuation in compensation signals during operation may result
in vibration.
2. If reverse run is used for lifting and forward run is used for lowering, the torque compensation signal polar-
IMPORTANT
ity must be reversed.
Analog Input Filter Time Constant
If noise enters the analog frequency reference during operation using analog frequency reference (b1-01 = 1),
and operation becomes rough, implement noise countermeasures and also set H3-12 (Analog input filter time
constant) to between 0.01 and 0.10 s.

Confirming Startup Current and Reducing Carrier Frequency

When performing a trial operation, set L8-41 (Current Alarm) to 1 (Enabled) and check the motor current
using the peak hold current monitoring function (U1-83) of the Digital Operator or a clamp ammeter, with and
without a mechanical load. An extremely high current will flow if the motor torque at start is insufficient, or if
timing is not correct and the motor locks with the holding brake.
If a current exceeding 150% of the Inverter rated current flows, the IGBT in the Inverter will be subject to heat
stress, resulting in a shortened life span.
In this case, take measures such as retuning and reduction of the load to reduce the current to a value less than
150% of the Inverter rated current.
Unless low noise operation is required, reduce the Inverter carrier frequency to a value between 2 kHz and 2.5
kHz to reduce the influence of heat stress.
OFF
ON
OFF
ON
Analog signals corresponding to load size
Same as above
OFF
ON
OPEN
CLOSE
Using Inverters for Elevating Machines
(Regenerative load: Inputs positive polarity.)
(Motor load: Inputs negative polarity.)
t
(Regenerative load)
(Motor load)
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