Toshiba TOSVERT VF-S15 Instruction Manual page 4

f297 : Low voltage operation upper limit frequency
When Low voltage operation upper limit frequency (f297) =0.0, this function is disabled. When this
function is activated, set this parameter larger than 0.1Hz.
During low voltage operation, frequency set with this parameter is the upper limit frequency. Even
though the frequency is set to the value lower than Lower limit frequency (ll), Low voltage operation
upper limit frequency (f297) is the upper limit.
Low voltage operation upper limit frequency (f297) is calculated as follows;
f297<(vl/vlv)×(Battery voltage/ 2 )
As battery voltage lowers by operation, leave the margin for the value of the Low voltage operation
upper limit frequency. In addition, if the voltage to the motor is lower than the V/F value, current
increases. Set Low voltage operation upper limit frequency using the above formula to avoid such
current increase.
[Example]
In case vl=60Hz, vlv=200V, and battery voltage =DC120V
f297<25Hz:
Set about 20Hz.
f298 : Low voltage operation DC voltage
This is the lowest voltage for the low voltage operation. Undervoltage protection (moff) will be
cancelled for the voltage higher than the voltage set with this parameter.
f298 < battery voltage (Vdc)
In order to leave the margin, set the low value comparing to the battery voltage actually used.
[Example]
In case 200V class inverter and battery voltage = DC120V
f298<120V:
Set about 100V.
■Setting example of input terminal
In case of setting low voltage operation signal to Terminal S1
Title
f114
Input terminal selection 4A (S1)
Set value 137 is the inversion signal.
Note 1: Low voltage operation signal is enabled only when the inverter is in undervoltage status. Turn on this
signal while the inverter is in undervoltage status. If this signal is input during operation, the inverter
does not recognize Low voltage operation signal.
Note 2: Normal operation is enabled during low voltage operation, but output frequency is controlled by Low
voltage operation upper frequency (f297).
Function Arrangement range
0-203
3
E6581918
Default setting
136
(Low voltage operation signal)