Specifications
96
■ Power-factor
Improvement
(Elimination of Phase
Advance Capacitor)
■ Radio Frequency
Interference
■ Wire Thickness and
Cable Length
To improve the power-factor, install an AC reactor or DC reactor on the inverter
,
s primary
side. DC reactor is built in 18.5 to 110 kW, 200 V class inverters and 18.5 to 300 kW, 400 V
class inverters. Power-factor improvement capacitor or surge suppressors on the inverter
output side will be damaged by the harmonic component in the inverter output. Also, the
overcurrent caused in the inverter output will trigger the overcurrent protection. To avoid
this, do not use capacitors or surge suppressors in the inverter
,
s output.
Because the inverter input and output (main circuit) contains a higher harmonics
component, it may emit RFI noise to communication equipment (AM radio, etc.) near the
inverter. Use a noise filter to decrease the noise. Use of a metalic conduit between the
inverter and motor or grouding the conduit is also effective. Proper routing of input and
output lead is also recommended.
If a long cable is used between the inverter and a motor (especially when low frequency is
output ), motor torque decreases because of voltage drop in the cable. Use sufficiently thick
wire.
When a digital operator is to be installed separately from the inverter, use the YASKAWA
remote interface and special connection cable (option). For remote control with analog
signals, connect the operating pot or operating signal terminal to the inverter within 50 m.
The cable must be routed separately from power circuits (main circuit and relay sequence
circuit) so that it is not subjected to inductive interference by other equipment. If
frequencies are set not only from the digital operator but also with external frequency
controller, use twisted-pair shielded wire as shown in the following figure and connect the
shielding to terminal E.
External
Frequency
Reference
2 kΩ
2 kΩ
0 to ＋10 V
4 to 20 mA
0 to ＋10 V
PP
PP
O V
O V
AC
RP
A2
A3
A1
＋V
Shielded Wire
Connection Terminal
E（G）
Speed Setting Power
＋15 V 20 mA
Master Reference
0 to ＋10 V (20 kΩ)
Master Reference
4 to 20 mA (250 Ω) or
0 to ＋10 V (20 kΩ)
Multi-function
Analog Input
0 to 10V (20 kΩ)