The ADD-A-PHASE static converter efficiently produces symmetrical three phase currents from a single phase source. The name signifies the addition of a phase to the existing single phase power, achieved through an autotransformer, a capacitor bank, and the motor’s impedance. This combination introduces a third phase, resulting in symmetrical three phase power. Consequently, the motor operates as if it were connected to a three phase power line, ensuring optimal performance and reliability.
Standard ADD-A-PHASE converters are available with horsepower ratings ranging from 1 HP to 100 HP. Units up to 150 HP have also been constructed. For high horsepower loads, it is essential to consult with the power supplier to ensure the single phase line capacity is sufficient to handle the load.
The ADD-A-PHASE converter is successfully used to operate motors on a variety of equipment. Key applications include pumps, fans, valve actuators, oil pump jacks, and piston-type compressors. These converters provide reliable three-phase power, ensuring optimal performance across diverse industrial and commercial applications.
The standard ADD-A-PHASE, Type 2S, can satisfactorily operate motor speeds of 3,600 RPM and 1,800 RPM. For motor speeds below 1,200 RPM, the ECONO-PHASE® Shifter may be a more suitable choice, depending on the motor’s power factor.
Yes, special ADD-A-PHASE models are available. For detailed information and specific requirements, please consult our sales team directly at 1-800-221-7665.
No, the ADD-A-PHASE converter is not available for 120 V input operation.
Yes, the basic ADD-A-PHASE types are designed for 60 cycle operation, but 50 cycle units are also available. For pricing and delivery details, please consult our sales team directly at 1-800-221-7665.
Yes, ADD-A-PHASE units are available for 480 V operation and are cataloged. For 575 V operation, please consult the RONK ELECTRICAL for specific details and availability.
Yes, most air conditioners can be operated with the Type 2SAC ADD-A-PHASE. For systems with additional three-phase motors, such as evaporator fan motors, the Type K-Duo is required for multiple-motor operation.
Yes, ADD-A-PHASE can be used with submersible pumps. It is important to check the motor's full load amp (FLA) rating. If the FLA of the submersible motor is higher than that of a standard NEMA motor with equivalent horsepower, the ADD-A-PHASE Type SUB should be used.
Yes, the Type "3" ADD-A-PHASE is designed for applications where it is necessary to operate 480V three phase motors from a 240V single-phase line. This is often desirable for large motors, submersible pumps, and similar equipment due to considerations like voltage drop, wiring size, and starter size. Other special voltages, such as 240V in / 208V out, are also available. For pricing and specific details, please consult our sales team at 1-800-221-7665.
The ADD-A-PHASE converter draws close to a unity power factor while the motor is starting and running, resulting in lower line current and reduced losses in line voltage. Additionally, the inrush current of the ADD-A-PHASE and three phase motor is only 3 to 4 times the running current, which helps in minimizing the impact on the utility's power distribution system.
Yes, the ADD-A-PHASE is the only static converter that allows a three phase motor to produce 100% rated power due to its autotransformer design. It even supports continuous overload operation equal to the permissible overload of the average three phase motor (1.15). However, some motor manufacturers, especially those of submersible pump motors, may not warranty their motors if operated into the service factor range while powered by a phase converter. To ensure normal equipment life expectancy, it is advisable to avoid service factor operation when possible.
It is not recommended to operate a motor larger than the rating of the ADD-A-PHASE converter. However, there may be specific applications where the motor load is reduced and within the converter's rating. Extreme caution should be exercised, and it is advisable to contact RONK ELECTRICAL before attempting such an operation to ensure safety and proper functionality.
Yes, the ADD-A-PHASE converter can operate smaller motors. The design of the autotransformer converter allows for smaller motors to be operated with appropriate capacitor adjustments.
Yes, the Type K-Duo ADD-A-PHASE is specifically designed for the independent or simultaneous operation of two motors. Additionally, special models are available for other multiple motor applications. For specific recommendations and custom solutions, please contact the RONK sales team.
Yes, RONK offers converters designed to operate two-speed applications. The Type K-Duo or Type AA ADD-A-PHASE can be used for some two-speed motors. For specific recommendations and custom solutions, please consult the RONK sales team.
Although ADD-A-PHASE is primarily designed for indoor installation, its louvered enclosure is drip-proof and can be mounted outdoors.
Yes, ADD-A-PHASE can be installed in damp underground locations. It has been successfully used in numerous applications, such as underground sewage lift stations.
No, ADD-A-PHASE is not available in an explosion-proof enclosure. The normal heat rise of components requires sufficient cooling, making an explosion-proof case impractical.
The components selected and manufactured for ADD-A-PHASE have a lifespan comparable to that of an average three-phase motor. Long life and reduced maintenance are among the many advantages of ADD-A-PHASE over conventional single phase motors.
The ADD-A-PHASE, being a static device with minimal moving parts, requires very little maintenance. If replacement parts are needed, immediate shipment can be arranged from factory stocks, or parts can be easily sourced locally.
ADD-A-PHASE is warranted to be free from defects in material and workmanship under normal use and service for one year from the date of installation or 18 months from the original date of shipment, whichever comes first. A postpaid warranty validation card is included with each unit, which must be completed and returned to the factory within 15 days of installation to validate the warranty.
ROTO-CON and ROTOVERTER are rotary phase converters that generate three phase current from a single phase supply. This enables the use of three phase motors and equipment in locations where installing a commercial three phase supply is impractical or too expensive. The ROTO-LOAD CENTER is a customized converter system that utilizes either of these rotary converters for specialized applications.
Single phase motors are available in limited types and may not be suitable for certain machinery. Many machines come with three phase motors pre-installed, which are mechanically simpler and generally more cost-effective than single phase motors. Single phase motors often lack the performance characteristics required by the load and are less efficient compared to three phase motors operated by a converter. A properly applied phase converter allows the operation of three phase equipment from a single phase service while maintaining the simplicity of three phase motors and controls. Additionally, if three phase service becomes available in the future, the equipment will be ready for operation.
A rotary converter consists of a rotary base unit and one or more capacitor panels. The base unit resembles an integral horsepower three phase motor but without a shaft extending from the endbell. One capacitor panel connects to the base unit, and together they provide three phase power. Additional capacitor panels may be connected on the load side of the starter(s) for larger motors. The base unit's induction rotor, with its two bearings, is the only moving part. It has no brushes or switches and requires minimal maintenance other than bearing lubrication.
The patented ROTOVERTER is the only rotary phase converter that employs a tapped winding. This tap adjustment feature allows for better current balancing compared to standard rotary converters, thereby providing maximum equipment performance. Converters without a tapped winding, such as RONK ROTO-CON, are suitable for applications where motors are not fully loaded and three phase current balancing is not critical.
Satisfactory operation requires the best converter for the job, and RONK provides a broad product line and the expertise necessary to ensure optimal performance for any application.
Autotransformer-capacitor type static converters, like ADD-A-PHASE, are ideal for constant load applications such as fans or pumps with one or two motors. They offer excellent starting torque, high efficiency, and seamless integration with automated controls, allowing the motor to operate at its rated load.
ROTO-CON and ROTOVERTER are recommended for applications involving multiple motors or significant load variations. These rotary converters provide flexibility, lower initial costs, and are also suitable for resistive heating loads. For rectifier or electronic loads, such as CNC machine tools, the ROTO-LOAD CENTER, which utilizes a rotary converter, is typically recommended.
The selection of a converter depends on the load to be operated. For accurate recommendations, it is important to consult RONK sales engineers, who can provide guidance based on a detailed listing of the loads to be managed.
ROTO-CON and ROTOVERTER converters are rated in kVA. Typically, approximately 1 HP can be operated for each kVA of the converter’s rating.
An individual motor with a horsepower rating of up to one-half the kVA rating can be operated on a Type P ROTO-CON or a Type C ROTOVERTER. The Type D ROTOVERTER and Type D-1 ROTO-CON are capable of starting single motors with horsepower nearly equal to the converter’s kVA rating.
Many applications involve two or three large motors along with several smaller motors. A relatively simple solution, such as split capacitor panels, is available to maintain good three phase balance under these conditions. For specific recommendations, consult with RONK sales engineers.
If the converter is set up for maximum load, the smallest horsepower load should be at least 15% of the converter’s total HP rating. ROTO-CON and ROTOVERTER are designed to maintain good three phase balance as motor loads vary from this minimum to the full rating of the converter. Motors with horsepower ratings below this 15% minimum can be operated if another motor rated above the 15% minimum operates simultaneously. For electronic or non-motor loads, please consult the RONK ELECTRICAL sales team.
Type D ROTOVERTER is generally recommended for single equipment pieces with varying loads or when a large number of small motors, relative to the total load, are involved. Type 2D-1 ROTO-CON is most often used to operate electronic and rectifier loads that require three phase power. Some electronic loads may require a customized converter, such as the ROTO-LOAD CENTER.
Type C ROTOVERTER is recommended when the majority of the load consists of one or two larger motors operating continuously near full load, where good current balance between phases is necessary. Additional motors may run simultaneously. An example would be grain drying fans that operate continuously, along with grain handling equipment running at times.
ROTO-CON is recommended for applications where current balance is less critical, such as machine tools, woodworking equipment, welders, grain handling, or center pivot irrigation systems. These loads generally do not operate near their full load rating or come on intermittently, making precise current balance less essential. ROTO-CON is also suitable for most electronic or resistive heat loads.
Yes, ROTO-CON and ROTOVERTER can operate multiple speed motors, which have different characteristics at various speeds and can be considered as several motors in one frame. Variable speed motor drives, being rectifier loads, require special consideration. For specific recommendations, please consult the RONK sales team at 1-800-221-7665.
Yes, motors applied to loads requiring high starting torque may need an auxiliary starting panel. The starting panel, connected to the load side of the motor starter, can provide up to 200% of full load torque during starting. Standard starting panels are limited to 20 starts per hour, with special panels available for higher start frequencies. Without the panel, starting torque will be approximately equal to full load torque, which may be inadequate for high starting torque or high inertia loads. Additional starting torque can also be achieved by using an oversized converter or by starting other motors before the hard-starting load.
Yes, standard ROTO-CON or ROTOVERTER can be used for reversing applications, as there is no limit on motor starts per hour. However, care must be taken to ensure proper phasing of control circuits and capacitors (if any) on the load side of the starter. For plug reversing applications, special compensation is required, and the RONK sales team should be consulted for specific recommendations.
Yes, ROTO-CON and ROTOVERTER can operate both delta and wye wound motors. The type of winding does not affect the operation of these converters.
Yes, single phase loads, such as control circuits, can be supplied from the ROTO-CON or ROTOVERTER by connecting them to the “B” and “C” phases, which are the single phase lines passing through the unit. RONK labels the manufactured phase as “A.” Large single phase loads may also be connected to phases “B” and “C” if the additional current is accounted for during wiring. Connection of single phase loads to phase “A” is not recommended; consult RONK ELECTRICAL if such a connection is necessary.
While converters are primarily used with motor loads, ROTO-CON and Type D ROTOVERTER also perform well with non-motor loads. Due to the variety of load characteristics, it is advisable to consult the sales team for recommendations. To ensure proper sizing for electronic loads, specify the maximum and minimum load and voltage tolerances. The ROTO-LOAD CENTER, utilizing either of these rotary converters, may be recommended for applications with special considerations.
RONK offers various modifications to ensure satisfactory operation of any load with ROTO-CON and ROTOVERTER converters. The most common modification for ROTOVERTER is split panels on Type C for multiple large motors. Converters can also be supplied with contactors for starting the converter or integrating it into automated control circuits. The ROTO-LOAD CENTER can be designed to provide improved voltage regulation for electronic loads or customized packages.
Yes, it is advisable to consult the power supplier before purchasing any equipment that involves a significant increase in load. Provide the supplier with the equipment location, a list of motors involved, and the horsepower of each motor, including full load amperage, maximum starting amperage, and voltage.
The effect on power lines will vary depending on their capacity and existing loads. However, the converters' high power factor and ability to limit inrush currents generally make them a favorable load for the power supplier’s lines.
The transformer should have a kVA rating equal to or greater than the rating of the converter, plus the kVA required to accommodate any additional single phase loads connected to the transformer.
The full load current of ROTO-CON and ROTOVERTER is noted on the converter nameplate (approximately 4.5 amps per kVA at 240 V). Single phase fuses should be sized at least 115% of this current, and wire size should be based on at least 125% of this current, unless excepted by Code (455-6,7). Ensure the wire size prevents excessive voltage drop in long runs. For single-panel units, size the three phase wiring as for standard three phase systems. For two-panel units, size the three phase wire at 135% of the three phase load’s amperage. All fuses or breakers should be time-delay types to allow for starting the converter and motors. Fuse non-motor loads as you would on three phase power. All wiring should be done by a qualified electrician according to applicable electrical safety codes. Refer to Section 455 of the NEC for rules governing converter installations.
ROTO-CON and ROTOVERTER serve as three phase power sources and should be treated similarly to a three phase service. When motors are located a considerable distance from the converter, careful consideration must be given to wire size to avoid excessive voltage drop during motor starting.
Yes, all integral horsepower three phase electric motors should be protected with magnetic starters and suitable overload protection. Magnetic starters are also necessary to prevent simultaneous starting of the converter and load following a power interruption.
The standard rotary transformer and control panels are drip-proof and may be mounted outdoors. The converter operates within an ambient temperature range of -30°C to 40°C (-25°F to 105°F). Shading from direct sunlight will result in cooler operation and extend component life. Ensure that dirt, snow, ice, or other materials do not obstruct rotation or ventilation of the rotary transformer. Avoid exposure to fertilizers or corrosive chemicals. TEFC units are available if environmental conditions warrant their use.
ROTO-CON and ROTOVERTER will start and operate below rated voltage. However, low voltage results in lower motor starting torque and higher amperage for a given motor load. Most applications require at least 220V (440V) at full load when operated from a 240V (480V) source. If lower voltages are present, consult RONK for guidance.
Higher line voltage above 255V (510V) can adversely affect the converter or load. If your single phase voltage exceeds these limits, contact your power supplier to explore options for reducing it.
Yes, field adjustments may be necessary after installation. ROTOVERTER is designed with provisions for adjustments to optimize performance for specific applications. Although factory-adjusted for satisfactory operation in most cases, phase currents and amperages should be checked under various loading conditions. Capacitance and tap connections should be adjusted as needed per the installation instructions. ROTO-CON, however, does not have adjustable taps; only the capacitance can be adjusted on these units.
The rotary transformer is started by a single phase power source and the capacitance of the connected panel. The converter must reach full speed before any load is applied. Two single phase input lines are connected directly to two of the three phase output lines, while the third line is manufactured by the combination of the rotary transformer and capacitors, creating a three phase output with proper phase angles.
Operating the converter without any load is usually impractical, as it consumes power without performing work. However, if the application requires continuous no-load operation, the converter can handle it. For situations with considerable idle time, it is advisable to consult RONK for guidance.
Maximum power loss occurs when the converter is idle: approximately 120 watts/kVA for Type D ROTOVERTER and Type D-1 ROTO-CON, and 40 watts/kVA for Type C ROTOVERTER and Type 2P ROTO-CON. When a load is applied, converter losses are typically about one-third of the idle values. Proper balancing ensures no appreciable change in motor efficiency.
Motor starting torque is influenced by several factors and is generally lower than when starting on a three-phase line. For applications requiring high inertia loads or high starting torque, it is advisable to consult RONK's sales team with the specific details to ensure proper operation and performance.
ROTO-CON and ROTOVERTER do not limit the number of motor starts per hour. However, standard auxiliary starting panels are limited to 20 starts per hour for each motor. If more starts per hour are required and a start panel is needed, please consult RONK for appropriate recommendations.
Motor breakdown torque, like starting torque, depends on several factors, including the motor size relative to the converter size and the number of other running motors. Breakdown torque is typically around twice the full load torque. This can be improved by using a Type D or D-1 converter, or by running other lightly loaded motors simultaneously.
ROTO-CON and ROTOVERTER are designed for applications where a significant portion of the load may be switched on or off during operation. Balance will vary with loading but is generally acceptable for total loads from 15% to 100% of the converter’s rated total horsepower load. In most applications, ROTOVERTER provides better balance, typically within 10% or less, compared to 15% or less for ROTO-CON.
Type D ROTOVERTER is often recommended for motor loads with many relatively small motors. It typically achieves good voltage balance for total loads from 10% to 100% of the converter’s rated total horsepower load, with current balance usually within 10%.
A properly applied rotary converter is designed to provide acceptable three phase power to the equipment. For many non-motor applications, different loads on each phase are common, so it is advisable to measure voltages rather than currents when checking the converter’s outputs for proper balance. Some electronic loads may require isolation transformers to ensure improved voltage stability to the load.
If operational problems arise, consult the troubleshooting guide in the service manual. If the issue persists, contact RONK's support team with the unit's serial numbers, a complete description of the problem, and phase currents and voltages labeled as “A,” “B,” and “C,” as identified in the converter.
Yes, an electrician experienced in motor service work is typically qualified to service ROTO-CON or ROTOVERTER. The electrician should read the connecting instructions, operating manual, and wiring diagram before performing any service. Technical assistance and service literature are available from RONK's support team.
ROTO-CON and ROTOVERTER are designed to operate for many years with minimal maintenance, as there are no moving parts except the rotor in the base unit. The rotor bearings, greased at the factory, should be lubricated according to the recommendations for an equivalent frame motor based on hours of operation. For specific recommendations, consult RONK or a local motor shop. The oil capacitors in the capacitor panel are UL recognized, non-PCB capacitors with a very long lifespan and require no maintenance.
RONK maintains replacement parts and factory repair facilities for all ROTO-CON and ROTOVERTER models. Consult RONK before any service or parts replacement during the warranty period. The parts used in the converters are generally common types available locally through electrical distributors and motor repair shops. Most repairs can be handled locally, and technical assistance is available from the RONK support team.
