PRECAUTIONS FOR USE OF THE INVERTER
This chapter explains the precautions for use of this product.
Always read the instructions before use.
For the separated converter type, refer to the "PRECAUTIONS FOR USE OF THE INVERTER" in the FR-F802 (Separated
Converter Type) Instruction Manual (Hardware).
For the IP55 compatible model, refer to the "PRECAUTIONS FOR USE OF THE INVERTER" in the FR-F806 (IP55/UL Type
12 specification) Instruction Manual (Hardware).
Electro-magnetic interference (EMI) and leakage
Leakage currents and countermeasures
Capacitances exist between the inverter I/O cables, other cables and earth and in the motor, through which a leakage current
flows. Since its value depends on the static capacitances, carrier frequency, etc., low acoustic noise operation at the increased
carrier frequency of the inverter will increase the leakage current. Therefore, take the following countermeasures. Select the
earth leakage current breaker according to its rated sensitivity current, independently of the carrier frequency setting.
To-earth (ground) leakage currents
Leakage currents may flow not only into the inverter's own line but also into the other lines through the earthing (grounding)
cable, etc. These leakage currents may operate earth leakage circuit breakers and earth leakage relays unnecessarily.
• If the carrier frequency setting is high, decrease the Pr.72 PWM frequency selection setting.
Note that motor noise increases. Selecting Pr.240 Soft-PWM operation selection makes the sound inoffensive.
• By using earth leakage circuit breakers designed for harmonic and surge suppression in the inverter's own line and other
line, operation can be performed with the carrier frequency kept high (with low noise).
• Long wiring will increase the leakage current.
• High motor capacity will increase the leakage current. The leakage current of the 400 V class is larger than that of the 200 V
Line-to-line leakage currents
Harmonics of leakage currents flowing in static capacitances between the inverter output cables may operate the external
thermal relay unnecessarily. When the wiring length is long (50 m or more) for the 400 V class small-capacity models (FR-
F840-00170(7.5K) or lower), the external thermal relay is likely to operate unnecessarily because the ratio of the leakage
current to the rated motor current increases.
Line-to-line leakage current example (200 V class)
The leakage currents of the 400 V class are about twice as large.
3. PRECAUTIONS FOR USE OF THE INVERTER
3.1 Electro-magnetic interference (EMI) and leakage currents
Wiring length 50 m
Leakage current (mA)
Wiring length 100 m
• Motor: SF-JR 4P
• Carrier frequency: 14.5 kHz
• Cable: 2 mm
, 4 cores
• Cabtyre cable