Guardian Technologies 4759, 4456, 4390, 4389, 4760, 4758 Electrical Units, Ohms LAW, Ampere, Volt

GENERAL INFORMATION

PART 1

SECTION 1.4

TESTING, CLEANING AND DRYING

If proper procedures are used, the following conditions can be detected using a VOM:

❏A "short-to-ground" condition in any stator or rotor winding.

❏Shorting together of any two parallel stator windings.

❏Shorting together of any two isolated stator windings.

❏An open condition in any stator or rotor winding.

Component testing may require a specific resistance value or a test for INFINITY or CONTINUITY. INFINITY is an OPEN condition between two electrical points, which would read as no resistance on a VOM. CONTINUITY is a CLOSED condition between two electrical points, which would be indicated as very low resistance or ZERO on a VOM.

ELECTRICAL UNITS

AMPERE:

The rate of electron flow in a circuit is represented by the AMPERE. The ampere is the number of electrons flowing past a given point at a given time. One AMPERE is equal to just slightly more than six thousand million billion electrons per second.

With alternating current (AC), the electrons flow first in one direction, then reverse and move in the opposite direction. They will repeat this cycle at regular intervals. A wave diagram, called a "sine wave" shows that current goes from zero to maximum positive value, then reverses and goes from zero to maximum negative value. Two reversals of current flow is called a cycle. The number of cycles per second is called frequency and is usually stated in "Hertz".

VOLT:

The VOLT is the unit used to measure electrical PRESSURE, or the difference in electrical potential that causes electrons to flow. Very few electrons will flow when voltage is weak. More electrons will flow as voltage becomes stronger. VOLTAGE may be considered to be a state of unbalance and current flow as an attempt to regain balance. One volt is the amount of EMF that will cause a current of 1 ampere to flow through 1 ohm of resistance.

OHM:

The OHM is the unit of RESISTANCE. In every circuit there is a natural resistance or opposition to the flow of electrons. When an EMF is applied to a complete circuit, the electrons are forced to flow in a single direction rather than their free or orbiting pattern. The resistance of a conductor depends on (a) its physical makeup, (b) its cross-sectional area, (c) its length, and (d) its temperature. As the conductor’s temperature increases, its resistance increases in direct proportion. One (1) ohm of resistance will permit one (1) ampere of current to flow when one (1) volt of electromotive force (EMF) is applied.

Figure 4. Electrical Units

OHM'S LAW

A definite and exact relationship exists between VOLTS, OHMS and AMPERES. The value of one can be calculated when the value of the other two are known. Ohm’s Law states that in any circuit the current will increase when voltage increases but resistance remains the same, and current will decrease when resistance Increases and voltage remains the same.

Figure 5.

If AMPERES is unknown while VOLTS and OHMS are known, use the following formula:

AMPERES = VOLTSOHMS

If VOLTS is unknown while AMPERES and OHMS are known, use the following formula:

VOLTS = AMPERES x OHMS

If OHMS is unknown but VOLTS and AMPERES are known, use the following:

OHMS =	VOLTS
	AMPERES

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