Wiring - Mitsubishi Electric FR-A800 Series Beginner's Manual

EM-compatible installation
FR-A846 inverters (IP55 compatible model)
These types of inverter have been approved as products for a UL type12 enclosure that is suitable for
Installation in a Compartment Handling Conditioned Air (Plenum).
● Install the inverter so that the inverter surrounding air temperature, humidity and atmosphere
satisfy the specifications (refer to section 1.2).
● The drive must be installed in clean air according to enclosure classification.
● Cooling air must be clean, free from corrosive materials and electrically conductive dust regarding
the UL Type 12 enclosure.
● This enclosure provides protection from airborne dust and light sprays or splashing water from
all directions.
3.3.2

Wiring

All analog and digital signal cables should be shielded or routed in metal cable conduits.
At the entrance point to the chassis run the cable through a metal cable gland or fasten it with a P or
U type cable clamp, connecting the shielding to the earth either with the gland or the clamp (see il-
lustration below). If you use a cable clamp install it as near as possible to the cable entry point to keep
the distance to the earthing point as short as possible. To keep the unshielded portion of the cable
(RFI transmission antenna!) as short as possible ensure that the end of the motor cable shielding is as
close as possible to the connection terminal without causing a risk of earth faults or short circuits.
When using a P or U clamp make sure that the clamp is installed cleanly and that it does not pinch the
cable more than necessary.
Route control signal cables at least 30cm away from all power cables. Do not route the power supply
cables or the cables connecting the frequency inverter and the motor in parallel to control signal ca-
bles, telephone cables or data cables.
If possible, all control signal cables to and from the inverter should only be routed inside the earthed
switchgear cabinet. If routing control signal cables outside the cabinet is not possible always use
shielded cables, as signal cables can also function as antennas. The shielding of the cables must al-
ways be earthed. To prevent corruption of sensitive analog signals (e.g. the 0-5 V analog frequency
setting signal) by currents circulating in the earthing system it may be necessary to earth only one end
of the cable shielding. In such cases always earth the shielding at the inverter end of the cable.
Installation of standard ferrite cores on the signal cables can further improve RFI suppression. The ca-
ble should be wound around the core several times and the core should be installed as close to the in-
verter as possible.
Motor connection cables should always be as short as possible. Long cables can sometimes trigger
earth fault protection mechanisms. Avoid unnecessarily long cables and always use the shortest pos-
sible route for the cables. It should go without saying that the motor itself should also be properly
earthed.
3 - 8
Good installation
Cable shielding
P clamp
U clamp
Connections
Poor installation
The shielding
should not be
twisted like this.