Kb-electronics KBWA-23D Manuale Utente Scaricare il pdf (Pagina 14)

4.3 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 1 – 5 Hz (30 – 150 RPM) to ensure motor

current does not exceed the nameplate rating. Do not use motor if the motor

current exceeds the nameplate rating.

It is recommended that the drive be used with Inverter Duty or TENV

motors.

Inverter duty and most totally enclosed non-ventilated (TENV) motors can provide full

rated torque over an extended speed range without overheating. See Figure 3.

FIGURE 3

MAXIMUM ALLOWED MOTOR TORQUE vs. SPEED

1 2 ... 9 10 11 12 13 14 15 16 17 18 19 ... 35 36

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Kb-electronics KBWA-23D Manuale Utente Pagina 14