Larsen & Toubro C*2000 Series, Руководство пользователя

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Chapter 8 Application
8-19
Cx2000 AC Drive
 When the input power is cut off due to instant power failure, the inverter outputs Low voltage trip
(LV) to hold the output.
 When the power is restored, the inverter outputs the frequency before the low voltage trip and the
voltage is increased due to PI control.
 t1: If current is increasing over the preset level in H23, the rise in voltage will stop and the
frequency is decreased.
 t2: If the opposite of t1 occurs, the increase in voltage starts again and the decrease in frequency
stops.
 When the frequency and voltage are restored back to the nominal level, acceleration will continue
at the frequency before trip.
 Speed search operation is suitable for loads with high inertia. Stop the motor and restart when friction
in load is high.

LTVF-Cx100 keeps normal operation when instant power failure occurs and power is restored in 15
msec for the use of its inverter rating.

Inverter DC link voltage can vary depending on output load quantity. Therefore, Low Voltage trip may
occur when instant power failure is maintained over 15msec or output is higher than its rating.
 Instant power failure specification is applied when input voltage to Inverter is 200~230V AC for 230V
class, or 380~480V AC for 415V class.
8.12 Auto restart try
Group Code Item Set Value Setting Range Initial Unit
Function
group 2
H26 Number of Auto Restart try -
0 ~ 10
0
H27 Auto Restart time - 0.0~ 60.0 1.0 sec
 This parameter (H26) sets the number of times of auto restart.
 It is used to prevent the system down caused by internal protection function activated by the
causes such as noise.
 H26: Auto restart will become active after the time set in H27. H26 – [Number of Auto restart try] is
reduced by 1 when it is active. If the trip outnumbers the preset restart try, auto restart function is
deactivated. If the setting is reset via the control terminal or the STOP/RST key on the keypad, the
number of auto restart try set by user is automatically entered Set Value.

If there is no more trip occurring for 30 sec after Auto restart operation, the H26 is restored to the
preset value.
 When operation is stopped due to Low voltage (Lvt) or Emergency stop (EST), Inverter Overheat (Oht),
and Hardware Trip (HWt), Auto restart will be deactivated.
 After the H27- [Auto Restart time], the motor starts acceleration automatically via speed search (H22-
25).

The following pattern is shown when the H26 – [Number of auto restart try] is set to 2.