Eaton SPI9000 User Manual download pdf (Page 63)

Startup

9000X AF Drives MN04001004E—May 2011 www.eaton.com 53

Stator Resistance Measurement Using DC Brake at Start

1. Deﬁne the DC brake current (=motor nominal current)

(P1.4.8).

2. Set the DC brake time at start to 2 seconds (P1.4.11).

3. Give start command.

The drive will correct the stator impedance to improve the

motor torque calculation. This also improves slip

compensation accuracy. (Stator resistance voltage loss

compensation, see figure below.)

If the DC brake time at start is set back to zero, the

calculated stator impedance value goes back to default if the

drive’s power is switched off. (Identification will retain all

values in memory.)

Motor Current Equivalent Circuit

Change the motor control mode to the speed control (P1.6.1 = 1).

Change the V/f optimization (auto torque boost) to on if more

torque is needed on low frequencies (P1.6.2). Note, this will

increase motor voltage while loading motor, check motor

current draw.

Note: In high torque–low speed applications it is likely that

the motor will overheat. If the motor has to run a

prolonged time under these conditions, special

attention must be paid to cooling the motor.

Air

Gap

Flux

RotorStator

Voltage Loss on

Stator Resistance

V Across L

The Magnetizing

Voltage

V at the

Motor Terminals

= R

x I

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Eaton SPI9000 User Manual Page 63