Toshiba VF-SX - Manual (Page 25)

5-6 TOSHIBA
5.5 Installation of an External Overload Relay
1. An electronic overload relay is standard on the VF-SX drive. However, for
the following applications Toshiba recomtnends Installing an overload relay that
coordinates with the internal solid state relay and the motor connected to the
drive. Connect the external relay between the drive and the motor.
A. When using a motor with non-standard current ratings, or the motor
ratings are not comparable to standard duty motors.
B. When operating a single motor smaller than the rating of the drive.
C. When operating several motors simultaneously from the drive. In this
case Install an overload relay on EACH motor.
2. When applying the VF-SX drive to a constant torque load, change the
electronic overload characteristics, or Install a separate overload relay. See
Chapter 11, Parameter [
bHrj.
3. When a motor continuously runs at low speeds it is recommended to use a motor
with an Internal overload relay, for additional protection.
5.6 Installation of an input Reactor
An input reactor Is used to suppress high frequency elements and sudden changes
In power fluctuations. Install an Input reactor when the Inverter Is connected
to electrical systems with the any of the following characteristics:
1. When the power capacity Is 200 KVA or more and the power capacity is
10 times or more than the Inverter capacity.
2. When the Inverter Is connected to the same system as a thyristor
commutation type controller.
3. When the inverter Is wired to an electrical system which also
contains a distortion source such as an arc furnace or a large
capacity inverter.
5.7 Incorrect Wiring and Incorrect External Components
WARHINS:
DO NOT INSTALL A POWER FACTOR IHPROVEHENT CAPACITOR ON THE INVERTER INPUT OR
OUTPUT. Current and voltage surges associated with the use of power factor
capacitors can damage the drive components.
If power factor correction is required add an optional input line reactor to
correct power factor.