Understanding STAR-DELTA Starter
Introduction The theory of applying reduced voltage to a motor to alter the motor torque and power consumption characteristics has existed for many years. These concepts have flourished due to the need to limit torque and limited generator/power distribution capabilities. Energy conservation initiatives have forced local governments to place mandatory reduced voltage starting requirements on motors rated at 7.5 Hp (5.5 kW) and larger. You can accomplish reduced-voltage starting through various methods, including part winding, wound rotor, autotransformer, wye-delta, or solid-state.
While many of these techniques require specialty motors or special system components, the wye-delta and solid-state methods are the simplest to apply. Applications that are used in the United States differ, but over the years the dominant method worldwide has been the wye-delta or star-delta starting technique.
The latest generation of soft starters and Smart Motor Controllers (SMCs) offers significant advantages over its predecessors when it comes to using it in wye-delta applications. In most cases, you can use these solid-state products to replace or retrofit any of the traditional reduced-voltage methods. We have designed the SMC product line to take full advantage of solid-state technology and advanced features. This design allows the controller to provide a cost-effective modular solution to both new and existing reduced-voltage applications.
The star delta starter of induction motor is designed to reduce high starting current and torque. The star delta starter is designed by three magnetic contactors, an overload relay, timer relay and circuit breaker. For Starter, a motor must be connected in delta mode position during a normal run. When induction motor is start in direct online.
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