Schneider Electric ALTIVAR 58 TRX - Manual (Page 205)

Class 8839 Econoflex™ AC Drives
Application Information
205
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APPLICATION INFORMATION (CONTINUED)
Speed Range and Regulation
The Econoflex Drive Controller operates within the range of 0.1 to 500 Hz. Factory setting is at 60 Hz.
Please note, if operating motor above base speed, the motor manufacturer must approve this type of
operation.
Accelerating Torque
AC induction motors built to NEMA standards are designed to provide starting torque which must meet
certain minimum ratings. This is normally expressed as a percentage of full load torque. These torque
ratings are valid only for full voltage starting where inrush current can be approximately 600% of motor
full load current. The Econoflex Drive Controller will limit starting current to a value usually not more than
110% (Variable Toque rated) of drive full load current, which provides approximately 110% starting
toque for VT loads.
AC Drives provide better torque per ampere than any other reduced current method, but the starting
torque available may be less than the starting torque available with an across-the-line starter.
Applications with known high starting torque requirements should be carefully evaluated. It may be
necessary to oversize the drive controller or the motor to provide the necessary accelerating torque.
Follower Signals
The Econoflex Drive Controller is designed to accept either a 4 to 20 mAdc or 3 to 15 PSI (Mod C09) or
0-10 Vdc (Mod J09) signal.
Bypass Operation
Although the Econoflex is designed for maximum reliability, it is possible that a controller could be out
of service when required to operate. Critical operations which can tolerate little or no down time should
be considered for a bypass (full speed) circuit.
The bypass circuit consists of an isolation contactor and bypass contactor mechanically and electrically
isolated. The isolation contactor disconnects the motor from the power converter. The Bypass contactor
closes and operates the motor across-the-line.
Enclosure Types
The Econoflex Drive Controller is available in a Type 1 or Type 12 K enclosure. Type 12 K is a
Type 12 with conduit knockouts.
Motor Selection
Econoflex Drive Controllers are designed to operate with any three phase AC squirrel cage induction
motor or synchronous reluctance motor having voltage and current rating compatible with the Drive
Controller.
The motor should meet NEMA MG1, Part 31 standards. The Part 31 standard calls for 1600 Volt rated
magnet wire, while the Part 30 standard calls for 1000 Volt rated magnet wire. The higher voltage rated
magnet wire will protect against possible premature motor failures due to voltage stress from fast dv/dt
rise times commonly seen with IGBT based AC Drives.