Selecting Motors And Inverters; Motor Output Torque Characteristics - Fuji Electric FRENIC-HVAC User Manual

3.1

Selecting Motors and Inverters

When selecting a general-purpose inverter, first select a motor and then inverter as follows:
(1) Key point for selecting a motor: Determine what kind of load machine is to be used, calculate its
moment of inertia, and then select the appropriate motor capacity.
(2) Key point for selecting an inverter: Taking into account the operation requirements (e.g.,
acceleration time, deceleration time, and frequency in operation) of the load machine to be driven
by the motor selected in (1) above, calculate the acceleration/deceleration/braking torque.
This section describes the selection procedure for (1) and (2) above. First, it explains the output torque
obtained by using the motor driven by the inverter (FRENIC-HVAC).
3.1.1

Motor output torque characteristics

Figures 3.1 and 3.2 graph the output torque characteristics of motors at the rated output frequency
individually for 50 Hz and 60 Hz base. The horizontal and vertical axes show the output frequency and
output torque (%), respectively. Curves (a) through (d) depend on the running conditions.
250
200
180
150
100
50
0
-50
-100
-150
-200
-250
Figure 3.1 Output Torque Characteristics (Base frequency: 50 Hz)

3.1 Selecting Motors and Inverters

(c)
(b)
(a)
5 0 6 0
(d)
3-1
Output
frequency
(Hz)