calls for a higher voltage at the start and at low rpm
values.
In systems with motors connected in parallel, the elec-
tronic thermal relay (ETR) of the frequency converter
cannot be used as motor protection for the individual
motor. Consequently, additional motor protection is
required, such as thermistors in each motor (or indi-
vidual thermal relays) suitable for frequency converter
use.
Please note that the individual motor cable for each
motor must be summed and is not to exceed the total
motor cable length permitted.
Motor thermal protection
The electronic thermal relay in UL-approved frequency
converters has received the UL-approval for single
motor protection when parameter 128 has been set for
ETR Trip
and parameter 105 has been programmed to
the rated motor current (see motor nameplate).
Electrical installation - brake cable
(Only standard with brake and extended with brake.
Typecode: SB, EB, DE, PB).
No.
Function
81, 82
Brake resistor terminals
The connection cable to the brake resistor must be
screened. Connect the screen by means of cable
clamps to the conductive back plate at the frequency
converter and to the metal cabinet of the brake resis-
tor.
Size the brake cable cross-section to match the brake
torque. See also Brake instructions, MI.90.FX.YY and
MI.50.SX.YY for further information regarding safe in-
stallation.
NB!
Please note that voltages up to 1099 V
DC, depending on the supply voltage,
may occur on the terminals.
Electrical installation - brake resistor temperature
switch
Torque: 0.5-0.6 Nm
Screw size: M3
No.
Function
106, 104, 105
Brake resistor temperature switch.
NB!
This function is only available on VLT
5032-5052, 200-240 V; VLT 5122-5552,
380-500 V; and VLT 5042-5602, 525-690
V.
If the temperature of the brake resistor
gets too high and the thermal switch drops
out, the frequency converter will stop
braking. The motor will start coasting.
A KLIXON switch must be installed that is
'normally closed'. If this function is not
used, 106 and 104 must be short-circuited
together.
Electrical installation - loadsharing
(Only extended with typecode EB, EX, DE, DX).
No.
Function
88, 89
Loadsharing
Terminals for loadsharing
The connection cable must be screened and the max.
length from the frequency converter to the DC bar is
25 metres.
Load sharing enables linking of the DC intermediate
circuits of several frequency converters.
NB!
Please note that voltages up to 1099 V DC
may occur on the terminals.
Load sharing calls for extra equipment.
For further information please consult
Loadsharing Instructions MI.50.NX.XX.
VLT
®
5000 Design Guide
64
MG.52.B2.02 - VLT
®
is a registered Danfoss trademark