20
4
IMPORTANT APPLICATION INFORMATION
4.1
Motor with External Fan Cooling –
Most totally enclosed fan-cooled (TEFC) and open
ventilated 3-phase AC induction motors will overheat if used beyond a limited speed range at
full torque. Therefore, it is necessary to reduce motor load as speed is decreased.
Note:
Some fan-cooled motors can be used over a wider speed range. Consult the motor
manufacturer for details.
WARNING!
Some motors have low speed characteristics which cause overheating and
winding failure under light load or no load conditions. If the motor is operated in this
manner for an extended period of time, it is recommended that the unloaded motor current be
checked from 2–15 Hz (60 – 450 RPM) to ensure motor current does not exceed the name-
plate rating.
Do not use motor if the motor current exceeds the nameplate rating.
FIGURE 4 – EXPANDED VIEW OF JUMPERS AND TRIMPOTS
J1
CON3
J2
PW
R
ST
50/60Hz
F - S - R
CON2
A/M
J1
P2
P3
CON1
X1 X2
P1
DEC/B
MIN
MAX
CL
ACC
COMP
230V 115V
(Models 2984, 2987 Only)
Jumpers and Trimpots
(Located on Lower PC Board)
Line Voltage Selection Jumper J1
(Located on Upper PC Board)
(Shown in Factory Setting)
