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A. C. Drives
Yaskawa Drives from Carotron cover a wide range of applications. The V1000 and P1000 models are cost-effective open-loop vector drives for fans, pumps, conveyors and other simple applications. The A1000 and GA800 models offer open-loop or closed-loop capability for handling more difficult applications which require tighter speed regulation, wide constant torque speed range or torque control capability. The U1000 model is an advanced matrix design drive that has full speed or torque control with line regen capability. The U1000’s advanced design also mitigates line and load harmonics without the need of external components. Yaskawa drives from Carotron cover a power range from fractional to 1,000 HP. Nema 1 and chassis mount units are standard with options for NEMA 12 and NEMA 4 enclosures for some models.
Teco Westinghouse Drives
Teco Westinghouse AC Drives from Carotron offer open-loop and closed-loop vector designs from fractional to 800 HP. The Teco E510 is designed for simple applications like pumps, fans and conveyors in power ratings up to 75HP. The Teco A510 can be used for general purpose constant torque applications with open-loop or closed-loop configurations in power ratings up to 400 HP. The Teco F510 is specifically designed for variable torque applications with special control features for pump and fan control in power ratings up to 800 HP.
Lenze-AC Tech Drives
Lenze – AC Tech drives from Carotron offer economical solutions to OEM’s and users for simple application like pumps, fans and conveyors. The SMV open-loop vector models are currently offered in NEMA 1 enclosures up to 60 HP and NEMA 4X enclosures up to 30 HP. The MC models offer a volts/Hz control design for simple applications up to 150 HP. The variety of ratings offered in NEMA 4X enclosures make the Lenze-AC Tech models attractive in wash down applications in the food and beverage industry.
KB Electronics AC Drives
KB Electronics AC Drives from Carotron offer cost effective solutions for OEMS and Users for simple single motor control applications. Many of the models offered allow for 115/230 VAC single phase input with 0-230 VAC, 3 Ph output to power fractional – 2HP AC motors. Other models are more traditional accepting 230 VAC, 3 PH input for 0-230 VAC, 3 PH output at ratings up to 3HP or 460 VAC, 3PH input for 0-460 VAC, 3 PH output at ratings up to 5 HP. KBVF and KBDF models offer small chassis mount units. KBWA, KBWK, KBMA and KBMK models offer simple NEMA 1 enclosed units. KBAC and KBDA models offer rugged NEMA 4X units for indoor or outdoor applications. KB Electronics offers simple analog control or digital programming to meet a broad range of customer requirements.
US Drives from Carotron are the perfect solution for heavy industry applications with ratings from 3-3500 HP. They can handle sawmills, metal forming machines, kilns, vibratory feeders, rock crushers, grinders and other applications with shock loading or cyclical loading. The bus follower design allows US Drives to ride through many shock load applications without the need for dynamic braking. Typical AC drives without the bus follower feature would normally trip on bus over-voltage or require dynamic or regenerative braking. The DX drives offer open-loop vector controls and the EX drives offer closed-loop encoder feedback for application that require tighter speed control. US Drives also offer a line regen package that can be added to any of their models to return regenerative energy to the AC lines for controlled stopping and tensioning applications. Chassis mount, Nema 1, NEMA 12 and NEMA 4 enclosures are offered for the drives.
About AC Drives
An AC Drive is a device that regulates the speed and torque of an AC electric motor. Utility AC power is typically converted to a DC bus supply within the AC Drive which is then output to an AC induction motor or permanent magnet AC motor via a three-phase IGBT bridge. The output frequency of the AC Drive is used to set motor speed and the output voltage is proportioned to the frequency to control motor torque.
Simple AC Drive applications require no speed feedback from the motor since an AC motor’s speed tracks the applied frequency within the slip rating of the motor (typically 2-3%). For more precise applications, advanced AC Drives provide a means for closed-loop speed feedback from a motor mounted encoder. The speed feedback allows for tighter speed regulation (0.1-1%), torque regulation for tensioning applications and motor shaft position control for synchronizing multiple motors together.
AC motors are inherently regenerative. When applied with AC Dives, this can be a blessing or a curse. High inertia loads driven by AC Drives produce regenerative energy when the speed is commanded to slow down. Excessive regenerative energy cannot be absorbed by simple AC Drives. Typically a resistor must be used to absorb this energy by adding a Dynamic Braking Transistor to the AC Drive. Some AC Drives provide the Dynamic Braking Transistor built into the drive so only a braking resistor is required. Other AC Drives require that both be added. More advanced AC Drives can also be supplied which direct the regenerative energy back to the utility AC power where it can be absorbed and reused.
Why Have an AC Drive?AC induction motors are the backbone of the industry. AC Drives allow these motors to be controlled to match changing speed requirements and minimize the need for gear changes for different process speeds. Pumps, fans and conveyors can be optimized in speed for the best productivity and efficiency. AC Drives also reduce mechanical wear and tear by allowing the motor to be ramped up to speed rather than the jolt of starting the motor across the line. AC drives with advanced vector technology and closed-loop encoder feedback capability can also replace DC drives and some simple servo drives in continuous web handling applications. AC drives with line regen capability can also handle winding and unwinding application. These applications typically require inverter rated motors to handle wide speed ranges and provisions for encoder mounting.
Process control: AC Drives have isolated control circuits that make interfacing with PLC’s and process controllers very easy. Digital interface for start/stop, forward/reverse, and Jog are typically standard in AC Drives. Speed reference can typically be supplied by a potentiometer, by a process follower voltage/milliamp signal or by an encoder or frequency reference. Options can be supplied in more advanced AC Drives for Modbus or Ethernet control functions.
Reduced mechanical stress: AC Drives provide the ability to control the acceleration and deceleration of AC motors rather that the abrupt surge that is generated by starting a motor across the line. This reduces the stress applied to mechanical drive components that connect the motor to a machine. Reducing the mechanical stress allows for longer life in the motor, gear reducers, chain, sprockets, belts and sheaves. In some cases smaller components may even be used since the peak stress is greatly reduced and a cost savings benefit can be achieved.
Energy savings: Constant speed AC motors do not always effectively match the process changes in a machine application. They tend to waste energy because they are not operated to match the machine requirements. With AC Drives, the motor speed can easily be adjusted to the process and energy can be saved. Also, motors can be started and stopped more easily with AC Drives and reduce peak energy costs for the customer. In applications where motors are oversized, an AC Drive can allow the applied motor voltage to be reduced so that the power consumption is matched to the load conditions to save energy without affecting the process speed.
Where Are AC Drives Used?The most common use for AC Drives is for pumps, fans and conveyors. These applications can typically use a simple AC drive design in conjunction with a standard motor since the speed range is usually less than 10:1 and most pumps and fans are variable torque loads. Constant torque applications generally require an AC motor designed for wider speed ranges with auxiliary cooling and adapters for motor mounted encoders. Constant torque applications would include extruders, coaters, laminators, printers, paper machines, textile machines, and wire drawing machines.
Contact Carotron for AC Drives
Carotron wants to assist you in AC Drive selection and installation. Our application engineers can discuss your machine operating specifications and provide recommendations. With 31 years of experience, Carotron will help you find the AC Drive you need to meet your operating requirements. Contact us today with your application requirements or for more information about our products and services.