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Installation
Brake resistors with fixed cables
To reduce the electrical noise from the wires between the
brake resistor and the frequency converter, twist the wires.
For enhanced EMC performance a metal screen can be
used.
Illustration 3.17 Twisted Cables
3.2.3 Brake Cable
Max. length: 20 m shielded cable.
Ensure the connection cable to the brake resistor is
shielded. Connect the shielding to the conductive back
plate of the frequency converter and to the brake resistor
metal cabinet, using cable clamps.
3.3 Protective Functions
3.3.1 Overtemperature Protection
The Danfoss brake resistor MCE 101 is equipped with a
galvanic isolated temperature switch (PELV) that is closed
under normal operating conditions and open if the brake
resistor is overheated.
NOTICE
Use the temperature switch as overtemperature
protection feature to prevent damage of the brake
resistor caused by overtemperature. To prevent damage
to the brake resistor, perform an immediate stop or a
ramp down.
There are several ways the temperature switch can be
used:
The temperature switch as digital input to frequency
converter
Example 1
1.
Connect terminal T1 of the brake resistor to the
frequency converter terminal 12 or 13.
2.
Connect terminal T2 of the brake resistor to a
digital input e.g. terminal 18.
MG90O202
Design Guide
Automatic restart after enabling of the temperature
switch:
Select coast inverse for the selected digital input.
Prevent automatic restart:
Select latched start for the selected digital input.
NOTICE
Coast does not terminate the brake function.
Example 1
L1
L2
L3
PE
F1
91 92 93 95
U V W PE
96 97 98 99
Illustration 3.18 Temperature Switch in Brake Resistor
NOTICE
The temperature switch as input to the frequency
converter cannot be considered a primary safety
function.
In case of a malfunction in the brake IGBT, the frequency
converter and brake resistor are only protected by
disconnecting the mains supply to the frequency
converter. The temperature switch must be connected
disabling the mains supply to the frequency converter by
a contactor preventing dangerous overtemperatures.
Danfoss A/S © Rev. 05/2014 All rights reserved.
+24V
12
D - in
L1 L2 L3 PE
18
VLT
R-
81
R+
82
PE
99
M
3~
3
T1
T2
MCE 101
Brake resistor
RB1
RB2
PE
13
3
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