NATE Air Conditioning and Heat Pumps Practice Exam

What internal voltage is likely to be measured in an electronic air cleaner?

1. 24 V

2. 120 V

3. 380 V

4. 5,000 V

The correct answer is: 5,000 V

An electronic air cleaner typically operates by using high-voltage direct current (HVDC) to ionize particles in the air, allowing them to be attracted to collector plates within the unit. The internal voltage measured in these systems is usually very high, often reaching levels around 5,000 volts. This high voltage enables the effective ionization and subsequent removal of airborne contaminants, providing a more thorough cleaning of the air compared to standard filters. In contrast, while 24 V and 120 V are common voltages for control circuits or motors in HVAC systems, they are not representative of the operating voltages within an electronic air cleaner. Moreover, 380 V, which is typically used for three-phase power supply in larger systems, does not apply to the operation of residential electronic air cleaners. The significant contrast between the low voltages associated with other components and the much higher voltage necessary for the ionization process underscores why 5,000 V is the most appropriate measure within this context.