Toshiba VF-AS1 User Manual

E6581301!

M-2

(Continued)

Error
code

Description

Possible causes

Remedies

QN Inverter

overload

•Rapid acceleration is operated.
•The DC braking amount is too

large.

•The V/f setting is improper.
•A restart signal is input to the

rotating motor after a momentary
stop, etc.

•The load is too large.

•Increase the acceleration time CEE.
•Reduce the DC braking amount H and the

DC braking time H.

•Check the V/f parameter setting.
•Use WX (Auto-restart) and WXE (Regenerative

power ride-though control).

•Use an inverter with a larger rating.

QN Motor overload

•The V/f parameter is improperly

set.

•The motor is locked up.
•Low-speed operation is performed

continuously.

•An excessive load is applied to the

motor during operation.

•Check the V/f parameter setting.
•Check the load (operated machine).
•Check the QNO setting and adjust H

according to the sustainable overload in the motor
low-speed range.

•Reduce the DC braking amount H and the

DC braking time H.

QNT

Dynamic
braking resistor
overload

•Rapid deceleration is operated.
•Dynamic braking is too large.

•Increase the deceleration time FGE.
•Increase the capacity of dynamic braking resistor

(wattage) and adjust PBR capacity parameter
RDER.

Overvoltage
during
acceleration

•The input voltage fluctuates abnormally.
(1)The power supply has a capacity

of 500kVA or more.

(2)A power factor improvement

capacitor is opened and closed.

(3)A system using a thyrister is

connected to the same power
distribution line.

•A restart signal is input to the

rotating motor after a momentary
stop, etc.

•Insert a suitable input reactor.

•Use WX (Auto-restart) and WXE (Regenerative

power ride-though control).

Overvoltage
during
deceleration

•The deceleration time FGE is too

short (regenerative energy is too
large).

•The dynamic braking resistor has

a considerably large resistance.

•RD (Dynamic braking resistor) is OFF.

Overvoltage limit operation H
is OFF.

•The input voltage fluctuates abnormally.
(1)The power supply has a capacity

of 500kVA or more.

(2)A power factor improvement

capacitor is opened and closed.

(3)A system using a thyrister is

connected to the same power
distribution line.

•Increase the deceleration time FGE.

•Install a dynamic braking resistor.
•Decrease dynamic braking resistance. (Also reset

the RDT.)

•Set dynamic braking mode parameter RD

properly.

•Set overvoltage limit operation H properly.
•Insert a suitable input reactor.

Overvoltage
during fixed
speed operation

•The input voltage fluctuates abnormally.
(1)The power supply has a capacity

of 500kVA or more.

(2)A power factor improvement

capacitor is opened and closed.

(3)A system using a thyrister is connected

to the same power distribution line.

•The motor is in a regenerative

state because the load causes the
motor to run at a frequency higher
than the inverter output frequency.

•The undervoltage detection level

H is too low.

•Insert a suitable input reactor.

•Install a dynamic braking resistor.

•Check the undervoltage detection level H.

*QV

Overtorque

•Overtorque reaches to a detection

level during operation.

•Stall prevention operation was

performed continuously for a
length of time longer than that set
with H.

•Check system error.

•Check whether the motor is overloaded or the

brake is engaged.

*WE

Low current

•The output current decreased to a

low-current detection level during
operation.

•Check the suitable detection level for the system

(H).

•Contact your Toshiba distributor if the setting is correct.

*WR

Voltage drop in
main circuit

•The input voltage (in the main

circuit) is too low.

•Momentary power failure occurs

because undervoltage continues
longer than undervoltage detection
time H.

•Check the input voltage.
•To cope with a momentary stop due to

undervoltage, enable WXE (Regenerative power
ride-through control), WX (auto-restart control),
and H (Undervoltage detection time).

*Presence or absence of parameter trip can be selected.

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