In a home workshop, farm, garage or small business environment there is often a requirement for the operation of machinery driven by three phase induction motors where only a single phase electricity supply is available.

The TRANSWAVE Converter provides an artificial means by which a three-phase motor can be operated from a single-phase supply thereby offering a cost-effective solution to this dilemma. In most instances, no modification to the machine is necessary.

The Static Converter is designed to operate three phase motors with starting characteristics and duty cycles as generally experienced on machine tool applications. This style of converter is typically used in single operator environments where only one machine is used at a time.

The use of a Rotary Converter is recommended for working environments with a variety of operator and/or machine combinations Please consult the Rotary Converter page.

Currently, six sizes of static converter are available designed to operate single motor loads between 0.37kW (0.5hp) and 7.5kW (10hp) and multi-motor loads between 2.2kW (3hp) and 11.0kW (15hp). Both single-phase 220/240-volt and split-phase 440/480-volt electricity supplies can be accommodated.

For applications with single motors in excess of 7.5kW (10hp) or combinations of motors in excess of 11.0kW (15hp), please seek further advice. Enquiries are invited from machinery manufacturers wishing to incorporate custom-built assemblies into their equipment.

For specific single motor applications where equipment has a heavy starting load or is subjected to an abnormal surge current or duty cycle an alternative range of Static Converters is recommended. Compressors, Pumps, Extractor Fans and Vehicle Hoists fall into this category. Please consult the SMA Converter page.
 

The Static Converter is a passive device that depends upon an interaction between the converter and the driven motor to induce an artificial third phase.

Static Converter Rating

Each size of Static Converter has a minimum load, a maximum single-motor load (for starting reasons) and an overall multi-motor capacity. The minimum load corresponds to the smallest size of motor capable of operating independently from the Static Converter. Not every motor can induce a satisfactory electrical condition across the three phases. The maximum single motor load is approximately 60-70% of the overall capacity of the converter. This is a reflection of the starting losses incurred by the artificial supply.

Single or Multi-Motor operation

The output from the Static Converter takes the form of a 380/415-volt three-phase, neutral and earth industrial socket. All sizes of TRANSWAVE Converter offer a single-phase 240-volt facility for control circuits and small auxiliary loads. For multi-motor applications requiring more than one output from the converter, the use of a three-phase distribution board is recommended.

Any number of motors can be operated simultaneously from a static converter provided the converter rating is not exceeded, either on a single motor or multi-motor basis. When considering a Static Converter for the operation of a multi-motor application it is imperative that the largest motor is started first and switched off last. If this is impractical, the use of a Rotary Converter is recommended. Please consult the Rotary Converter page.

Power Regulating Switch

The Static Converter incorporates a power-regulating switch below the on/off switch. The operator is invited to select the optimum power level to suit the particular motor or combination of motors in circuit. This switch controls both the starting and running modes of the motor. For multi-motor applications the setting of the power regulating switch may have to be adjusted in line with increases and decreases in load. If this is impractical, the use of a Rotary Converter is recommended. Please consult the Rotary Converter page.

Starting Surge

All TRANSWAVE Converters automatically control the motor starting surge, maintaining the surge until the motor has attained its full running speed irrespective of time taken. The operator need not leave the driven machine to reset the converter for starting.

Single-phase Ammeter

Most STC converters are fitted with an ammeter indicating the single-phase current drawn. At any time, the operator can see at a glance whether the motor is being subjected to an overload condition.

Special Applications

The use of a Rotary Converter is recommended for three-phase applications with small motors, motors of unusual magnetic characteristics (i.e. multi-speed) or motors subjected to abnormal short term overload conditions such as guillotines or power presses. This style of converter should also be considered for applications where the motor is frequently stopped and started or where the direction of the motor is constantly changed (e.g. screw-cutting). Please consult the Rotary Converter page.

Fractional Horsepower Motors

Where machinery incorporates ancillary motors of a fractional horsepower nature (e.g. suds/coolant pump; table traverse/feed; table rise/fall) these motors are likely to fall below the minimum load of a Static Converter. Under such circumstances, it is imperative that these motors are operated in conjunction with and not independently of the main drive motor. If this is impractical, the use of a Rotary Converter is recommended. Please consult the Rotary Converter page.