Control Techniques Unidrive LV Series Installation Manual page 12

Frequency / speed
0
Current
150%
100%
0
2
0 20
Figure 2–2 Standard S4/S5 duty cycle
(Unidrive LFT LV)
Unidrive LV and Unidrive VTC LV Refer
to Table 2–5 to find the maximum continuous
output current that can be obtained for the
required ambient temperature and
switching frequency. The maximum
PWM
ambient temperature can be 40°C or 50°C
(104°F or 122°F). Note that the nominal power
rating of the Drive may not be achieved above
40°C.
Operation in a maximum
ambient temperature of 50° ° C
(122° ° F)
Caution
Unless the precaution described
here is taken, the Drive will
limit the maximum continuous
output current only to the
value for 40° ° C, and not to the
value stated in Table 2–5 for
50° ° C.
Make a note of the value for
50° ° C; you will need to refer to
it when you reach Configuring
the Drive for the motor in
Chapter 2 of the User Guide.
At that point, ensure that the
value to be entered in
parameter 0.46 Motor – rated
current does not exceed the
noted value.
2-6 Installing the Drive
50Hz
1500
RPM
Unidrive LFT LV Refer to Table 2–6 to find
the maximum continuous output current that
can be obtained for the ambient temperature
for a standard S4/S5 duty-cycle or for
continuous operation. Refer to a Drive Centre
or distributor for information on other duty
ratios.
Make a note of this step number and the
following:
•
Unidrive LV and Unidrive VTC LV
Chosen maximum ambient temperature.
•
Unidrive LV and Unidrive VTC LV
60
Chosen
each Drive.
•
All Unidrive LV versions From Table 2–
7, the maximum power dissipation (heat)
figure (P P
frequency for each Drive (this figure is the
total power dissipation at the maximum
continuous output current available at the
chosen
includes power dissipated in option modules
when fitted). Power dissipation in the
Unidrive LFT is the same as that for the
standard Unidrive when operating at 9kHz
switching frequency.
PWM
•
Unidrive LV and Unidrive VTC LV If
the maximum ambient temperature will be
50°C (122°F), note the value of the
maximum permissible output current
obtained from Table 2–5. This will be the
maximum value that parameter 0.46 Motor
– rated current should be set at.
switching frequency for
PWM
) at the chosen
PWM
DISS DISS
switching frequency, and
PWM
Unidrive LV model sizes 1 to 3 Installation Guide
switching
Issue code: uliu1