Guardian Technologies 4758 - Manual (Page 16)

SECTION 1.4
TESTING, CLEANING AND DRYING
GENERAL INFORMATION
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 = VOLTS
OHMS
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
PART 1
Page 1.4-3