Savch S2800 Series, User Manual

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79
11-04:
0: Protection inhibited
1: Protection permitted
In the course of inverter deceleration, the actual drop rate of inverter rotation speed may be
less than that of output frequency due to the effect of load inertia. At this moment, the motor
will send electric power back to inverter, making the bus voltage of inverter increased, which
may cause the over voltage fault if no measures taken.
Over voltage stall protection is used to detect the bus voltage in the course of inverter
operation and compare with the over load stall point defined by 11-05 (corresponding to
standard bus voltage). If the bus voltage exceeds the over load stall point, the output
frequency of inverter stops decreasing and continues to decelerate until the bus voltage is
lower than over voltage stall point. As the diagram showns below:
When the frequency drop rate of instant power-failure is set as 0, the function of frequency
drop of instant power-failure is unavailable.
Frequency drop point of instant power-failure: it refers to that after power lost is received by
the power grid and the voltage falls to the frequency drop point of instant power-failure, the
inverter begins to decrease the operation frequency as the frequency drop rate of instant
power-failure (11-03), which makes the motor in electricity generate state and the generate
power is able to maintain the bus voltage,so as to ensure the normal operation of inverter
until the inverter gets power again.
Note: when the power grid switched, if adjust these two parameters properly,the production
stop can be avoided due to the inverter protection .
Factory setting 1
Setting range 0: Protection inhibited
1: Protection permitted
Over voltage stall protection
11-04
Factory setting 130
Setting range 110~150%[380V:130%]
110~150%[220V:120%]
Protection voltage on over voltage stall
11-05
over voltage stall function
over voltage
stall point
output
frequency
Time t
Time t
output current