Basic Electricity Module Competencies

Check the micro farad rating of a capacitor using a multi-meter

1. Disconnect the capacitor 2. Set the meter to capacitance 3. Read across the terminals 4. This meter reads 1.86μF Label says 5μF Bad Capacitor

Use a clamp on style amp probe to read current

1. Jaws clamp around a conductor 2. Jaws contain a coil of wire that reads the electromagnetic field being generated by the current flow in the wire. 3. Safe: you don't have to disconnect anything with the power on. 4. Read AC amps only.

Use the power formula to solve for power, voltage, current, and resistance

1. Power = Amps x Voltage 2. Volts = Power / Amps 3. Amps = Power / Volts 4. Resistance = Power / Amps (squared)

Define common electrical terms such as voltage, current, resistance, and power

1. Voltage: the force that pushes electrons through a conductor 2. Current: the actual flow of electrons through a conductor 3. Resistance: anything that opposes current flow 4. Power: the ability to do work

Use Ohm's Law to solve for voltage, current, and resistance in a parallel circuit

1. Volts = Amps x Resistance 2. Current = Volts / Resistance 3. Resistance = Volts / Amps

Use Ohm's Law to solve for voltage, current, and resistance in a series circuit

1. Volts = Amps x Resistance 2. Current = Volts / Resistance 3. Resistance = Volts / Amps

Explain the generation of AC power

A conductor is rotated through a magnetic field in which it cuts lines of force in that magnetic field. When the conductor cuts those lines of force an EMF is produced within the conductor.

Explain the difference between a "short" and an "open" and how each would be read using an ohm meter

A resistance value close to 0 ohms is referred to as a "short" and always results in excessive current value which will trip the circuit breaker. Conversely, an infinite amount of resistance offers an infinite amount of opposition to current flow, and no current will flow. This is referred to as an "open" circuit.

Explain the operation of an AC motor

AC motors use slip rings instead of commutators. They accomplish the same purpose of moving the current within the conductor to a load.

State the effects of wiring loads in series

Each load uses power, consequently lowering the power to each load consecutively.

Determine the conductor size required for a load given the full load amps

Resistance limits the current that can flow in a circuit. If there is too much resistance a load won't receive the proper amount of power. Proof (Power = Amps x Voltage). Loads and conductors offer some resistance. The smaller the conductor the more resistance to current. So basically, the conductor has to be a big enough gauge to allow the full load of amps to get to the load without too much opposing resistance.

To recognize common hvac electrical controls and their schematic symbols

See charts

Cite the rules regarding safety in taking voltage, current and resistance reading on a circuit

Very low amperages are fatal. Voltage can cause current to jump an air gap causing a spark (aka an arc flash). Must wear safety glasses. Avoid wearing metallic jewelry. Exposed metallic clothing accessories can be hazardous. Use the one hand rule.