Relay Output; Brake Resistors - Danfoss VLT Decentral Drive FCD 302 Design Manual

System Integration
3 3
20
18
12
20
18
12
Illustration 3.15 Input Polarity of Control Terminals
NOTE
To comply with EMC emission specifications, screened/
armoured cables are recommended. If an unscreened/
unarmoured cable is used. For more information, see
2.2.2 EMC Test Results.

3.4.1.5 Relay Output

The relay output with the terminals 01, 02, 03 and 04, 05,
06 has a capacity of maximum 240 V AC, 2 A. Minimum 24
V DC, 10 mA or 24 V AC, 100 mA. can be used for
indicating status and warnings. The two relays are
physically located on the installation card. These are
programmable through parameter group 5-4*. The relays
are Form C, meaning each has one normally open contact
and one normally closed contact on a single throw. The
contacts of each relay are rated for a maximum load of
240 V AC at 2 amps.
38
VLT
Safe
torque off
20 20 20 20 20 55 42
19 27 29 32 33 50 54
12 12 12 12 12 55 53
PNP (Source)
Digital input wiring
Safe
torque off
20 20 20 20 20 55 42
19 27 29 32 33 50 54
12 12 12 12 12 55 53
NPN (Sink)
Digital input wiring
MG04H102 - VLT
®
Decentral Drive FCD 302
Relay 1
•
Terminal 01: common
•
Terminal 02: normal open 240 V AC
•
Terminal 03: normal closed 240 V AC
Relay 2
•
Terminal 04: common
•
Terminal 05: normal open 240 V AC
•
Terminal 06: normal closed 240 V AC
Relay 1 and relay 2 are programmed in 5-40 Function Relay,
5-41 On Delay, Relay, and 5-42 Off Delay, Relay.
Illustration 3.16 Relay Connection

3.4.2 Brake Resistors

In certain applications, break down of kinetic energy is
required. In this frequency converter the energy is not fed
back to the grid. Instead the kinetic energy must be
transformed to heat, and this is achieved by braking using
a brake resistor.
In applications where the motor is used as a brake, energy
is generated in the motor and send back into the
frequency converter. If the energy can not be transported
back to the motor it will increase the voltage in the
converter DC-line. In applications with frequent braking
and/or high inertia loads this increase may lead to an over
voltage trip in the converter and finally a shut down. Brake
resistors are used to dissipate the excess energy resulting
from the regenerative braking. The resistor is selected in
respect to its ohmic value, its power dissipation rate and
its physical size. Danfoss Brake resistors are available in
several types, for internal or external installation to the
®
is a registered Danfoss trademark
Z
A
/Z
/A
B
+5V
/B
GND