Fuji Electric FRENIC-HVAC User Manual page 367

Nominal Applied Motor and Characteristic Factors when P99 (Motor 1 Selection) = 1
Nominal
Thermal time
applied
constant τ
motor
(Factory default)
(HP)
1 to 30 5 min
40 to 60
75 to 125 10 min
150 or above
If F10 is set to "2," changes of the output frequency do not affect the cooling effect. Therefore,
the overload detection level (F11) remains constant.
Overload detection level (F11)

F11 specifies the level at which the electronic thermal overload protection becomes activated.
- Data setting range: 1 to 135% of the rated current (allowable continuous drive current) of
the inverter
In general, set the F11 data to the allowable continuous current of motor when driven at the
base frequency (i.e. 1.0 to 1.1 times of the rated current of the motor.) To disable the
electronic thermal overload protection, set the F11 data to "OFF" (Disable).
Thermal time constant (F12)

F12 specifies the thermal time constant of the motor. If the current of 150% of the overload
detection level specified by F11 flows for the time specified by F12, the electronic thermal
overload protection becomes activated to detect the motor overload. The thermal time
constant for general-purpose motors including Fuji motors is approx. 5 minutes for motors of
30 HP or below and 10 minutes for motors of 40 HP or above by factory default.
- Data setting range: 0.5 to 75.0 (minutes)
(Example) When the F12 data is set at 5 minutes
As shown on the next page, the electronic thermal overload protection is activated to detect an
alarm condition (alarm code OL1) when the output current of 150% of the overload detection
level (specified by F11) flows for 5 minutes, and 120% for approx. 12.5 minutes.
The actual time required for issuing a motor overload alarm tends to be shorter than the
specified value, taking into account the time period from when the output current exceeds the
allowable continuous drive current (100%) until it reaches 150% of the overload detection
level.
Reference current Output frequency for
for setting the motor characteristic factor
thermal time
f2
constant (Imax)
Base
Allowable continuous
frequency
drive current × 150%
× 33%
6-57
6.3 Details of Function Codes
Characteristic
factor (%)
f3 α1 α2 α3
Base
frequency 69 90 90
× 33%
54 85 95
Base
frequency 51 95 95
× 83%
53 85 90