Sears 113.299131 - Manual (Page 23)

TROUBLE-SHOOTING TABLE-MOTOR
The following table lists some of the most common
troubles caused by low voltage, their causes and
suggested remedies:
NOTE: Motors used on wood-working tools
are particularly susceptible to the accumu­
lation of sawdust and wood chips and should
be blown out or "vacuumed" frequently to
prevent interference with normal motor
ventilation.
TROUBLE PROBABLE CAUSE REMEDY
Motor fails to develop
full power. (Power output
of motor decreases rapidly
with decrease in voltage
at motor terminals.) For
example: a reduction of
10 % in voltage causes a
reduction of 19% in
maximum power output of
which the motor is capable,
while a reduction of
20 %
in voltage causes a
reduction of 36% in maxi­
mum power output.
1. Power line overloaded with
lights, appliances and other
motors.
2. Undersize wires or circuit too
long.
3. General overloading of power
company's facilities. (In many
sections of the country, demand
for electrical power exceeds
the capacity of existing
generating and distribution
systems.)
1. Reduce line load.
2. Increase wire sizes, or reduce length of wiring.
3. Request a voltage check from the power company.
Motor starts slowly or 1. Low Voltage — will not trip 1. Correct low voltage condition.
fails to come up to full relay.
speed.
2. Starting relay not operating. 2. Have relay replaced.
Motor overheats. 1. Motor overloaded. 1. Correct overload condition.
2. Improper cooling. (Air 2. Clean out sawdust to provide normal air circulation
circulation restricted through
motor due to sawdust, etc.) through motor.
Starting relay in motor 1. Burned relay contacts (due to 1. Have relay replaced.
will not operate. extended hold-in periods
caused by low line voltage,
etc.).
2. Open relay coil. 2. Have relay replaced.
3. Loose or broken connections 3. Have wiring checked and repaired.
in motor terminal box.
Motor stalls (resulting in 1. Starting relay not operating. 1. Have relay replaced.
blown fuses or tripped
2. Voltage too low to permit
2. Request voltage check from power company.
circuit breakers).
motor to reach operating
speed.
3. Replace fuses or circuit breakers with proper
3. Fuses or circuit breakers do
not have sufficient capacity. capacity units.
Frequent opening of 1. Motor overloaded. 1. Reduce motor load.
fuses or circuit breakers.
2. Fuses or circuit breokers do
not have sufficient capacity.
2. Replace fuses ar circuit brsok^rS.
3. Starting relay not operating
(motor does not reach normal
speed).
3. Have relay replaced.
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