Danfoss VLT FCD 311 Design Manual page 20

Safety functions in connection with installation
When a brake resistor is installed, the best possible
endeavours should be made to avoid overloads, as
the heat generating from a brake resistor may in-
volve a fire risk.
NB!:
The brake resistor
should be fitted to a nonflammable material.
For protection of the installation, a thermal relay is
fitted that cuts out the frequency converter if the
brake current is too high. Danfoss' 40% brake resis-
Ordering numbers for brake resistors
Flatpack brake resistors IP 54
Type
303 (400 V)
305 (400 V)
307 (400 V)
311 (400 V)
315 (400 V)
322 (400 V)
330 (400 V)
20
P R
motor MIN
[kW] [ ]
0.37 747
0.55 747
0.75 558
1.10 387
1.50 297
2.20 198
3.00 135
®
VLT FCD Series
tors contain a KLIXON switch. Flat pack resistors
are self-protecting.
The brake current setting on the thermal relay is cal-
culated as follows:
THERMAL
I
R is the brake resistor value at any given time.
BR
The drawing shows an installation with a thermal re-
lay.
Size [ ] / [W] Duty cycle %
per item
830 / 100 W 20
830 / 100 W 20
620 / 100 W 14
430 / 100 W 8
310 / 200 W 16
210 / 200 W 9
150 / 200 W 5.5
MG.04.A1.02 - VLT is a registered Danfoss trade mark
r
AV G
= P
BR
R
Order no.
175Uxxxx
1000
1000
1001
1002
0984
0987
0989