4.1.3.5 Earthing connections in SOMANET Products
Table below shows the connection between the heat sink and V- which defines the earth connection.
Product
V- and
Chassis
Note
Circulo 7 and
9
Isolated
Node
400,1000,2000
Not
isolated
V- is connected to the chassis directly.
Braking
chopper
Isolated Because the mounting holes are connected to the V- plane in the PCB, the
isolation will break when a conductive Spacer is used between the mounting
holes on the PCB and chassis. This can violate an existing earthing system and if
a SELV power supply is used it may become PELV.
4.1.3.6 Earthing consideration (guidelines)
The drives generate a large amount of noise because high currents are switched.
In many use cases, the Motor enclosure is connected to a conductive part of a machine. The parasitic
capacitor of the motor is always an alternative pathway which causes common mode noise issues.
The image below shows an improper grounding. In this connection, there is no reliable connection from the
motor enclosure to the earth. In this circuit, the noise passes through the shielding and natural earth. The
earth impedance on the motor side (power side) is higher than on the control side, which causes a ground
loop issue.
In the next drawing, the motor is connected directly to a low impedance FE with a proper earth connection. In
this circuit, the noise passes through the earth cable.
The shielding is connected to the earth correctly, and there is no ground loop because of the unbalanced
impedance.
Synapticon Documentation
© 2021 Synapticon GmbH | Daimlerstraße 26 | D-71101 Schönaich Documentation v 4.19.0 | Built 2022-02-01
969/1031
