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H84, H85
Pre-excitation (Initial level, Time)
A motor generates torque with magnetic flux and torque current. Lag elements of the rising edge of magnetic flux causes a
phenomenon in which enough torque is not generated at the moment of the motor start. To obtain enough torque even at the
moment of motor start, enable the pre-excitation with H84 and H85 so that magnetic flux is established before a motor start.
Pre-excitation (Initial level) (H84)
Data setting range: 100 to 400 (%) (Ratio to the motor's no-load current)
H84 specifies the forcing function for the pre-excitation. It is used to shorten the pre-excitation time. Basically, there is no
need to modify the default setting.
Pre-excitation (Time) (H85)
Data setting range: 0.00 (Disable), 0.01 to 30.00 (s)
H85 specifies the pre-excitation time before starting operation. When a run command is inputted, the pre-excitation starts.
After the pre-excitation time specified by H85 has elapsed, the inverter judges magnetic flux to have been established and
starts acceleration. Specify H85 data so that enough time is secured for establishing magnetic flux. The appropriate value for
H85 data depends on the motor capacity. Use the default setting value of H13 data as a guide.
Pre-excitation--
EXITE
(E01 to E07, data = 32)
Turning this input signal ON starts pre-excitation.
After the delay time for establishing magnetic flux has elapsed, a run command is inputted. Inputting the run command
terminates pre-excitation and starts acceleration.
Use an external sequence to control the time for establishing magnetic flux.
Under V/f control (including auto torque boost and torque vector), pre-excitation is disabled, so use DC braking or
hold the starting frequency instead.
A transient phenomenon, which may occur when the amount of mechanical loss is small, may rotate the motor
during pre-excitation. If a motor rotation during pre-excitation is not allowed in your system, install a mechanical
brake or other mechanism to stop the motor.
Even if the motor stops due to pre-excitation, voltage is output to inverter's output terminals U, V, and W.
An electric shock may occur.
Summary of Contents for FRENIC-MEGA
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