NFO
Drives
AB
2021
201013
‐
2
Operating
and
Installation
Manual
26
P-Nom U-Nom
f-Nom
N-Nom
I-Nom
cos
R-stat
R-rot
L-main
Sigma
I-magn
I-limit
2.20 kW 400 V
50 Hz 1455 rpm 4.65 A
0,79
3.00
2.00
400 mH
0.080
1.80 A
5.80 A
Table 11. Default nominal motor data and motor parameters
Table 11 shows default values for nominal data and motor parameters. Please note that these parameters cannot
be measured from the motor terminal.
5.7.4 Motors in parallel
Several motors can be connected in parallel. If so, they must be of the same size and shall be equally loaded. For
correct tuning, sum up P-Nom and I-Nom for the motors before performing autotuning.
When running motors in parallel, separate motor protection should be mounted as they are not individually
protected by the electronic motor overload protection or inverter current limit.
5.8 Setting control parameters
5.8.1 Acceleration and deceleration ramps
Parameters
Acceleration
and
Deceleration
indicate how fast the motor is allowed to change speed. The units are in
seconds, and the value indicates the time it takes for the rotor frequency to change as much as the motor's nominal
frequency (
f-Nom
). The parameter values are calculated using the formulas below:
t
Accel
=
f-Nom
* Acceleration time desired / frequency change
t
Decel
=
f-Nom
* Deceleration time desired / frequency change
Example: a motor has a nominal frequency of 50Hz, and is to accelerate from 0 to 80 Hz in 2 sec and brake from
80 to 5 Hz in 9 sec.
t
Accel
= 50 * 2 / 80 = 1.25 s
t
Decel
= 50 * 9 / 75 = 6.00 s
The inverter cannot accelerate faster than its maximum torque allows. An acceleration time set too low
leads to the inverter limiting current which gives an extended acceleration time.
In generative operation, the inverter cannot brake harder than it can handle the motor's surplus energy. When
used, the brake chopper can help handle the surplus energy, but setting the retardation time too low may cause the
brake chopper circuit to become overloaded.
To enable different acceleration and deceleration times at start and/or stop, it is possible to set a breakpoint
frequency. When this is set to any other value than zero, it enables the alternative acceleration and deceleration
times, which are used from 0 Hz up to the breakpoint frequency.
External braking resistance must be fitted if the retardation time is less than 5 sec. Avoid setting
retardation ramp (parameter
Deceleration
) any shorter than necessary.
5.8.2 Phase
order
Parameter
Phase order
determines default rotation direction of the motor. If motor terminals (inverter output) U, V
and W are connected to motor terminals U, V and W in that sequence, the default setting
U-V-W
will render clock-
wise rotation for a positive setpoint. However, crossed over motor cables or some other property of the installation
may render the wrong desired rotation direction. This can be reversed by changing Phase order to
U-W-V
.
3006469-2022-04
