Quick Answer
Some appliances require more starting watts than others because they need a surge of power to initiate operation, often due to electrical motors or high-voltage electrical systems.
Starting Watts Requirements
Many appliances, especially those with electrical motors, have high starting watt requirements due to the initial surge needed to overcome mechanical resistance. For example, a refrigerator may require 900 watts to start but only 150 watts to maintain its operation. Similarly, a well pump might need 2,000 watts to start but only 500 watts to sustain its operation.
Factors Affecting Starting Watts
The following factors contribute to an appliance’s starting watts requirement:
- Type of motor: Induction motors, like those used in refrigerators and air conditioners, require more starting watts than permanent-split capacitor (PSC) motors. PSC motors, commonly found in well pumps and pool pumps, typically require less starting watts.
- Load resistance: High-load resistance, such as in a well pump, increases the starting watts requirement.
- Voltage tolerance: Appliances with low voltage tolerance may require more starting watts to compensate for voltage fluctuations.
- Efficiency and performance: High-performance appliances, like those with high-efficiency motors, may require more starting watts to achieve their rated performance.
Generator Sizing Considerations
When sizing a portable generator, it’s essential to consider the appliance’s starting watts requirement to ensure the generator can handle the surge. A general rule of thumb is to choose a generator with a capacity that’s 25% higher than the appliance’s rated wattage. For example, if a refrigerator requires 900 watts to start, choose a generator with at least 1,125 watts of capacity.
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