8.5 Additional Motor Information
8.5.1 Motor Cable
The motor must be connected to terminals U/T1/96, V/
T2/97, W/T3/98. Earth to terminal 99. All types of three-
phase asynchronous standard motors can be used with a
frequency converter unit. The factory setting is for
clockwise rotation with the frequency converter output
connected as follows:
Terminal No.
Function
96, 97, 98, 99
Mains U/T1, V/T2, W/T3
Earth
•
Terminal U/T1/96 connected
to U-phase
•
Terminal V/T2/97 connected
to V-phase
•
Terminal W/T3/98
connected to W-phase
96
97
U
V
96
97
98
U
V
W
98
W
130HA036.10
The direction of rotation can be changed by switching two phases in
the motor cable or by changing the setting of 4-10 Motor Speed
Direction.
Motor rotation check can be performed using
1-28 Motor
Rotation Check
and following the steps shown in the
display.
F frame Requirements
F1/F3 requirements: Motor phase cable quantities must be
multiples of 2, resulting in 2, 4, 6, or 8 (1 cable is not
allowed) to obtain equal amount of wires attached to both
inverter module terminals. The cables are required to be
equal length within 10% between the inverter module
terminals and the first common point of a phase. The
recommended common point is the motor terminals.
F2/F4 requirements: Motor phase cable quantities must be
multiples of 3, resulting in 3, 6, 9, or 12 (1 or 2 cables are
not allowed) to obtain equal amount of wires attached to
each inverter module terminal. The wires are required to
be equal length within 10% between the inverter module
terminals and the first common point of a phase. The
recommended common point is the motor terminals.
Output junction box requirements: The length, minimum
2.5 meters, and quantity of cables must be equal from
each inverter module to the common terminal in the
junction box.
NOTE
If a retrofit applications requires unequal amount of wires
per phase please consult the factory for requirements and
documentation or use the top/bottom entry side cabinet
option.
8.5.2 Motor Thermal Protection
The electronic thermal relay in the frequency converter has
received UL-approval for single motor protection, when
1-90 Motor Thermal Protection
is set for
ETR Trip
and
1-24 Motor Current
is set to the rated motor current (see
motor name plate).
For thermal motor protection it is also possible to use the
MCB 112 PTC Thermistor Card option. This card provides
ATEX certificate to protect motors in explosion hazardous
areas, Zone 1/21 and Zone 2/22. When
1-90 Motor Thermal
Protection
is set to [20] ATEX ETR is combined with the use
of MCB 112, it is possible to control an Ex-e motor in
explosion hazardous areas. Consult the programming
guide for details on how to set up the drive for safe
operation of Ex-e motors.
8.5.3 Parallel Connection of Motors
The frequency converter can control several parallel-
connected motors. When using parallel motor connection
following must be observed:
•
Recommended to run applications with parallel
motors in U/F mode par. 1-01 [0]. Set the U/F
graph in par. 1-55 and 1-56.
•
VCC
+
mode may be used in some applications.
•
The total current consumption of the motors
must not exceed the rated output current I
INV
for
the frequency converter.
•
If motor sizes are widely different in winding
resistance, starting problems may arise due to too
low motor voltage at low speed.
•
The electronic thermal relay (ETR) of the
frequency inverter cannot be used as motor
protection for the individual motor. Provide
further motor protection by e.g. thermistors in
each motor winding or individual thermal relays.
(Circuit breakers are not suitable as protection
device).
Installations with cables connected in a common joint as
shown in the first example in the picture is only
recommended for short cable lengths.
When motors are connected in parallel,
1-02 Flux Motor
Feedback Source
cannot be used, and
1-01 Motor Control
Principle
must be set to
Special motor characteristics (U/f)
.
Electrical Installation
FC 300 Design Guide
206
MG.33.BD.02 - VLT
®
is a registered Danfoss trademark
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