
Troubleshooting
7-
37
The frequency reference upper limit has been reached.
The output frequency upper limit is determined by the following formula:
Maximum Output Frequency (E1-04)
×
Frequency Reference Upper Limit (d2-01) / 100
Check to be sure that the constant E1-04 and d2-01 settings are suitable.
Acoustic Noise From the Motor
The carrier frequency is automatically reduced if a current exceeding 110% of the Inverter rated current flows
while the Inverter output frequency is low. When the carrier frequency is reduced, acoustic noise form the
motor will change.
If acoustic noise from the motor causes a problem, change L8-38 (Carrier frequency reduction selection) to 0
(Disabled). However, for mechanical loads that require repetitive high torque, such as with cranes, leave L8-
38 to 1 (Enabled) without changing.
Acoustic noise from the motor can be changed by changing the setting of L8-39 (Reduced carrier frequency).
(The minimum set value is 1.0 kHz for open-loop vector control.)
If Motor Overload (OL1) is Detected Even Though the Current is below
the Motor Rated Current
Take the following action if a motor overload (OL1) is detected even though the current is below the motor
rated current.
A general-purpose motor is being continuously operated at rated current, even in
low-frequency range.
For a general-purpose motor (standard motor), cooling ability is directly proportional to the fourth root of the
frequency (f
1/4
), i.e., it is lower at lower frequencies. For this reason, the motor may overheat in the low-fre-
quency range even at or below the motor rated current. This may cause an overload (OL1) to occur. Use a spe-
cial motor designed for the purpose to continuously operate the motor at the rated current, even in the low-
frequency range.
The Inverter’s output voltage is larger than the input voltage.
The Inverter cannot output a voltage that is greater than the input voltage. If the output voltage reference value
exceeds the Inverter’s maximum output voltage value, hunting will occur in the output current and a motor
overload (OL1) may be detected, even when the current is below the motor rated current. Decrease the setting
of E1-05 (Max. Voltage) or the setting of C4-01 (Torque Compensation Gain) to lower the output voltage ref-
erence value.
TOE-S616-60.1.book 37 ページ 2017年8月4日 金曜日 午後3時41分