Toshiba TOSVERT VF-S11 User Manual

E6581158
A-21
1
(2) Affects of leak current across lines
Power
supply
Inverter
Thermal relays
CT
A
M
Leak current path across wires
(1) Thermal relays
The high frequency component of current leaking into electrostatic capacity between inverter out-
put wires will increase the effective current values and make externally connected thermal relays
operate improperly. If the wires are more than 50 meters long, it will be easy for the external ther-
mal relay to operate improperly with models having motors of low rated current (several
A(ampere) or less), especially the 400V class low capacity (3.7kW or less) models, because the
leak current will increase in proportion to the motor rating.
Remedies:
1.Use the electronic thermal built into the inverter. (See 5.13)
The setting of the electronic thermal is done using parameter QNO, VJT.
2.Reduce the inverter's PWM carrier frequency. However, that will increase the motor's magnetic
noise.
The setting of PWM carrier frequency is done with the parameter H. (See 6.12)
3.This can be improved by installing 0.1µ~0.5µF - 1000V film capacitor to the input/output terminals of
each phase in the thermal relay.
U/T1
V/T2
W/T3
IM
Thermal rela
y
s

Toshiba TOSVERT VF-S11 Specifications

General

Model	TOSVERT VF-S11
Category	Inverter
Output Frequency	0.1-400Hz
Frequency Range	0.1-400Hz
Control Method	V/f Control, Sensorless Vector Control
Power Rating	0.2kW to 15kW
Cooling Method	Forced air cooling
Overload Capacity	150% for 60 seconds
Protection Features	Overcurrent, Overvoltage, Undervoltage, Overheat
Communication	Modbus RTU
Input Voltage	200-240V, 380-480V
Braking Unit	Built-in (optional external braking resistor)