HVAC School - For Techs, By Techs Some High Voltage Electrical Basics
This podcast is a high voltage A/C electrical class that Bryan gave to some of the Kalos apprentices.
The high voltage journey begins with basic electrical theory. Basically, a difference in charge is needed for electrons to move and generate power.
Motors, which are inductive loads, are the greatest users of power that we will encounter in the field. Inductive loads generate magnetism and utilize alternating current (AC) power. AC power is generated by a rotating magnetic field, and the direction of the current alternates. Comparatively, resistive loads generate light and heat, and direct current (DC) moves in one direction. Theoretically, we can use Ohm's law in the field to determine the voltage, amps, or resistance (ohms) without a meter, so long as we know two of the three values. However, we may not get an accurate measurement of ohms due to reactance on inductive loads.
The windings you will encounter in the field include common, start, and run. (Remember: the same side that feeds start feeds run.) In a PSC motor, the start winding stays in the circuit the entire time. When you ohm the windings, you will notice that common has the lowest resistance, run has moderate resistance, and start has high resistance. (Common to run + common to start = run to start). Universally, capacitors contain a brown, black, white, and brown-and-white wire. You can wire a capacitor in two different ways; one uses three wires, and the other uses four. The three-wire method caps off the brown-and-white wire, leaving it unused.
Join Bryan and the apprentices in their high voltage class as they cover:
- Basic Electrical Theory
- Potential Difference
- Basic Capacitance
- Motor Lead identification
- Different motor type
- Motor Direction
- Proper Wiring
- MOCP and MCA
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