Table of Contents
Advertisement
General remarks
When connecting cables, the following items must be observed:
-
When changing the power supply of the motor between the inverter and commercial power line, be sure
to install mechanically interlocked switches (S1 and S2) as shown in the figure below:
-
Install an earth leakage breaker at the input of the inverter. Select an earth leakage breaker which has a
short term delay and a higher trigger current.
When the cable between the inverter and the motor is more than 10 meters long, the thermal relay may
malfunction due to high-frequency waves. To prevent this, install an AC reactor on the output side of the
inverter or use a current sensor rather than a thermal relay.
-
In case a relay is connected to the digital output terminals 11 or 12 be sure to install a surge absorbing
diode in parallel to the relay. Otherwise the surge voltage created when the relay goes on or off may
damage the output circuit.
-
Be sure that the specified grounding is carried out. Separate the inverter´s grounding pole from those of
other heavy electric machinery and avoid using common grounding poles when multiple inverters are
employed.
-
Use a twisted and shielded wire when connecting signal lines to the control terminals and cut the
shielded covering as shown in the figure below. Make sure that the length of the signal line is 20 m or
less. If the line must be longer than 20 m then an appropriate signal amplifier should be used.
-
Use relays which are capable of reliably switching at a voltage of 24VDC and a current of 3mA.
-
Install the mains circuit cables at a safe distance from the control circuit cables. If the mains circuit
cables and the control circuit cables have to cross each other, this should be done at an angle of 90
degrees because interference can be minimized in this case.
Earth leakage
circuit breakers
Power
supply
Inverter 1
Inverter 2
Inverter 3
WRONG
Grounding point
Frame ground
S1
L1 (L)
U
L2
V
S2
L3 (N)
W
Inverter
Inverter 1
Inverter 2
Inverter 3
CORRECT
Isolate here
No grounding
necessary here
5-3
Chapter 5 – Wiring
Motor
Grounding point
Advertisement
Table of Contents
