Reduced Voltage Starting connects the motor windings/terminals at lower than normal line voltage during the initial starting period to reduce the inrush current when the motor starts. |
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• Reduced voltage starting may be required when: |
S The current in-rush form the motor starting adversely affects the voltage drop on the |
electrical system. |
S needed to reduce the mechanical “starting shock” on drive-lines and equipment when |
the motor starts. |
• Reducing the voltage reduces the current in-rush to the motor and also reduces the starting |
torque available when the motor starts. |
• All NEMA induction motors can will accept reduced voltage starting however it may not |
provide enough starting torque in some situations to drive certain specific loads. |
If the driven load or the power distribution system cannot accept a full voltage start, some type of reduced voltage or "soft" starting scheme must be used. |
• Typical reduced voltage starter types include: |
1. Solid State (Electronic) Starters 2. Primary Resistance Starters 3. Autotransformer Starters 4. Part Winding Starters 5. Wye-Delta Starters |
Reduced voltage starters can only be used where low starting torque is acceptable or a means exists to remove the load from the motor or application before it is stopped. |