Toshiba Tosvert VF-AS1 - Manual (Page 96)

E6581301
E-30
5
■ Gradient bias adjustment of analog monitor output
Here is an example of the adjustment of output from 0-20mA → 20-0mA, 4-20mA using the FM terminal.
H =, H= H =, H=
20
0 100%
0
(mA)
20
0 100%
0
(mA)
4
H =, H= H =, H=
large
(mA)
20
0
0
100%
small
(mA)
20
0
0
100%
4
+ The analog output inclination can be adjusted using the parameter HO.
5.17 PWM carrier frequency
EH : PWM carrier frequency
H : Random mode
H : Carrier frequency control mode selection
[Parameter setting]
Title Function Adjustment range Default setting
EH PWM carrier frequency
~()kHz [Upper limits differ by
applicable motor capacity.]
According to model
H Random mode :Disabled, : Enabled
H
Carrier frequency control
mode selection
:Not decrease carrier frequency automatically
:Decrease carrier frequency automatically
:Not decrease carrier frequency automatically,
400V class supported
:Decrease carrier frequency automatically,
400V class supported
Note 1: If the PWM carrier frequency is set at 2.0kHz or above, it cannot be decreased below 2.0kHz during
operation. Changes made to decrease the carrier frequency below 2.0kHz take effect when operation is
restarted after it is stopped.
Note 2: If the parameter setting is 1.9kHz or less, you cannot change the setting at 2.0kHz or more. Changes made
to increase the carrier frequency to 2.0kHz or above take effect immediately.
Note 3: If RV (V/f control mode selection) is set to , , , , or , the inverter sets a lower limit of 2.0kHz for
carrier frequencies.
Note 4: If you change the carrier frequency, you may need to reduce the inverter’s continuous output current.
Refer to Section 1.4.4, “Current reduction curve.”
Note 5: If the motor becomes overloaded when H is set to or (carrier frequency not decreased
automatically), an overload trip occurs.
Note 6: For the setting H= or to take effect, power needs to be turned off and then turned back on.
Note 7: When setting the carrier frequency (EH) between and .kHz, you are recommended to set H
below 130%.
• Function
1) The sound tone of acoustic noise can be changed by adjusting the PWM carrier frequency. This parameter is
also effective in preventing the motor from resonating with its load machine or its fan cover.
2) In addition, this parameter reduces the electromagnetic noise generated by the inverter. Reduce the carrier
frequency to reduce electromagnetic noise. Note: Although the electromagnetic noise level is reduced, the
magnetic noise of the motor is increased.
3) The random mode reduces motor magnetic noise by changing the pattern of the reduced carrier frequency.