As well as amplifiers, AuCom was also involved in the design of power supplies for radio broadcast systems, taxi alarms and energy saving devices for single phase and three phase ac induction motors. These energy saving devices were manufactured under a license agreement with the American space agency, NASA.  From here the electronic soft starter technology was born and this became the main focus of the company who produced the world’s first range of commercially viable soft starters.

Now AuCom expands the range to include a wider range of industrial electronics, motor control centres and switchgear to create a complete solution.

Throughout AuCom's history, AuCom has always been dedicated to innovation and research. Through a mix of agility and hard work AuCom keeps at the forefront of industrial electronic technology.

Max Korndörfer claimed four methods of using an autotransformer for reduced voltage motor starting. Three of the methods are not used by the industry and it is the 4th method of starting that has been in use for more than a hundred years

The fourth method is with the star switch closed and as the motor accelerates a change over is made from the reduced voltage tap on the autotransformer to direct-on-line.
 

 

Advantages
1. Heavy

2. Cheaper than typical dual-winding transformers
3. An auto transformer has higher efficiency than two winding transformer. This is because of less ohmic loss and core loss due to reduction of transformer material.
4. Auto transformer has better voltage regulation as voltage drop in resistance and reactance of the single winding is less. 

1. Auto Transformer is direct electrical connection between the Primary and Secondary circuit

2. Disadvantage of the Auto Transformer is that it does not have the Primary to secondary winding Isolation of a conventional Double Wound Transformer.

Since 1920, the autotransformer starter has been the most popular device for reducing the starting current inrush for induction motors; it provides maximum starting torque with minimum line current. 

 

 Starting Torque /Current with 3 Reduced Voltage taps

Voltage | 50%tap | 65%tap | 80%tap
Torque | 25% | 42% | 64%
Current | 50% | 65% | 80%
 

-Automatic star delta starter (closed circuit transition) 

 

As the motor accelerates, the current will begin to drop, but will not drop significantly until the motor is at a high speed. 

 

Provided the torque developed by the motor exceeds the load torque at all speeds during the start cycle, the motor will reach full speed. If the torque delivered by the motor is less than the torque of the load at any speed during the start cycle, the motor will stops accelerating. If the starting torque with a DOL starter is insufficient for the load, the motor must be replaced with a motor which can develop a higher starting torque.