Mechanical System - Scotsman TCL 180 Service Manual

Page 11
When the opposite situation occures, i.e. the
condenser temperature gets below the pre-fixed
ACCUMULATOR
CAPILLARY TUBE
COMPRESSOR
FAN MOTOR
limit, the temperature sensor changes again its
electrical resistance reducing therefore the
current flow to the P.C. Board to cause a tempo-
rary stop of the Fan Motor.
NOTE. In case the condenser temperature
probe senses that the condenser temperatu-
°
re has rised to 70 C (160
following abnormal reasons:
CLOGGED CONDENSER
FAN MOTOR OUT OF OPERATION
AMBIENT TEMPERATURE HIGHER THEN
° °
43 C (110 F)
it causes the total and immediate SHUT-
OFF of the machine in order to prevent the
unit from operating in abnormal and
dangerous conditions. When the ice maker
stops on account of this protective device,
there is a simultaneous glowing of the 2nd
RED LED, warning the user of the Hi Tem-
perature situation. After having eliminated
the source of the excessive condenser tem-
perature, to restart the ice machine it is
necessary to push the RE-SET button that
protrudes through the control box cover.
The 2nd RED LED starts blinking and
three minutes later the flaker unit resume its
normal operating mode.
The refrigerant suction or Lo-pressure sets - in
normal ambient conditions (21 °C) - on the value
of 1 bar (14 psig) after few minutes from the unit
start-up.
This value can vary of 0.1 or 0.2 bar (1.5
in relation to the water temperture variations
influencing the freezer cylinder.
NOTE. If, after ten minutes from the unit start
up, no ice is made and the evaporating
temperature detected by the evaporator
sensor results to be higher than -1 ° C (30 ° F)
the ice maker stops and the 3RD WARNING
YELLOW LED blinks.
EVAPORATOR
DISCHARGE LINE
°
F) for one of the
÷
3 psig)

MECHANICAL SYSTEM

The mechanical system of the SCOTSMAN
Nugget Ice Dispenser consists basically of a gear
motor assembly which drives, through a ratched
coupling, a worn shaft or auger placed on its
vertical axis within the freezing cylinder.
The gear motor is made of a single phase electric
motor with a permanent capacitor. This motor is
directly fitted in the gear case through which it
drives - in counter clockwise rotation at a speed
of 9.5 r.p.m. - the freezer auger being linked to it
by the ratched coupling.
NOTE. In the event the gear motor will tend
to rotate in the wrong direction (counter-
clockwise) or not rotating at all the unit will
stop immediately with the glowing of the
3RD WARNING YELLOW LED on account
of the intervention of the Electromagnetic
Safety Device - based on Hall Effect principle.
After having diagnosed and eliminated the
source of the failure, to restart the unit it is
necessary to press the RE-SET push button
or switch OFF and ON the power line main
disconnnect switch (Fig. 7).
The RED LED will start blinking and after
3 minutes the ice maker will resume its total
operations by running first the gear motor
and then the compressor.
FIG. 7
When the gear motor rotating speed is slowed
below 1300 r.p.m. from the normal speed of
1400 r.p.m. the Electromagnetic Safety Device
transmits an electrical signal to the
MICROPROCESSOR to stop immediately the
unit operations like it occures for the wrong
rotation, with the lighting-up of the 3RD YELLOW
WARNING LED. This to relieve from the
excessive load all the electrical and mechanical
components of the entire Drive System and extend
their durability.
NOTE. After having diagnosed and eliminated
the source of the gear motor slow rotation to
restart the unit it is necessary to press the
RE-SET push button or switch OFF and ON
the power line main switch.
NOTE. Any time the machine stops in alarm
the front four LED's start to blink.
Page 11
STEADY
WRONG-NO-SLOW ROTATION GEAR MOTOR