The RPM AC motor product line by Baldor performs like a high power servo motor with very low rotor inertia and high power density, and is now available in IEC frame sizes 112, 132, 160, 180 and 280 with permanent magnet (PM) rotor construction. The addition of the 280 frame size to the RPM AC PM family significantly increases the product power range with synchronous speed performance.
The latest addition of the finned laminated 280 frame version - the DL280 - extends the product line’s power output range to 600 kW (800 HP) in totally enclosed blower cooled (TEBC) IP55 form, and 900 kW (1200 HP) using open force-ventilated, IP23 type construction.
The motors have high efficiency performance that exceed IE3 levels. This is achieved by virtue of its highly power dense, low loss rotor design where the permanent magnets are actually embedded within the rotor laminations. This enables the motor to run cooler than conventional PM motors where the magnets are affixed to the outer surface of the rotor. This benefit can also lead to a smaller frame size in comparison to conventional PM motors.
PM rotor technology offers improved efficiency that can translate into increased power density with smaller frame sizes per unit of output power and synchronous (non-slip) speed control performance.
These motors are all designed to provide continuous constant torque performance from zero speed up to base speed for use with closed loop PM AC drives. The PM rotor technology allows the motor to operate at very low speeds, negating the need for a gearbox in the power train, and is equally capable of operating at very high speeds (up to 12,000 RPM) - enabled through the use of power matched PM AC drives.
Typical applications for RPM AC motors include automotive testing stands, extruders, winders/unwinders, metal forming and bending machinery, machine tool/spindle applications, and replacement of square frame DC motors. Another specific application area is in cooling towers, where a more compact PM motor can drive the tower fan directly from underneath, replacing all of the power train components in between motor and fan that are required with conventional solutions.
The RPM AC PM motor line is currently available in both IEC and NEMA frames (180, 210, 250, 280 and 440 frame sizes).