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4.3
Example of External Connection
Figure 4.1 shows an example of a connection of a motor control system containing only one
dynamic braking unit.
Always use discharging resistors equal to or more than the resistance specified. If the
resistance is insufficient, the dynamic braking unit may be damaged.
To prevent overheating and burning during any malfunction of the dynamic braking unit, devise
a circuit to shut off the primary power of the inverter by connecting this circuit to the alarm
contact terminals (AL1 and AL2).
Figure 4.2 shows the connection of a thermal relay and Table 4.2 shows a list of applicable
wires.
Note 1: Select relay RY according to the coil (Mg)
and contact (RY) specifications.
Note 2: R0, T0 terminals depend on inverter model.
External
resistor
Thermal relay
(Note 2)
(Note 1)
Dynamic braking unit
(Main unit)
Thermal relay
(Usually closed (b contact) and
opens when it is working)
Motor
Inverter
3-phase power supply
200V class
3-phase power supply
400V class
Power supply
Connection to the alarm terminal section
Figure 4.1 External connection example
To terminals of the external
resistor (when a 2-element 3-
terminal thermal relay is used)
To terminals of the external
resistor (when a 3-element
thermal relay is used)
To the dynamic braking unit
To the dynamic braking unit
Figure 4.2 Connection of a Thermal Relay
