Flooded Type Water Cooled Screw Chiller Technical M
anual
49
1.2 Main Parts of Electrical System
No.
Name
of
parts
Outline drawing and internal structural
drawing
Description
1
Contr
oller
Controller is used to
control movement of relay
through program, switch
on and off each part of
unit according to external
conditions such as
temperature and
pressure, and realize
automatic control of unit.
3
A/C
contac
tor
When electromagnetic coil of
contactor isn’t powered on,
reacting force of spring and
deadweight of armature core
keep main contact at
disconnected position. When
electromagnetic coil is
powered on, electromagnetic
force attracts armature
towards static iron core by
overcoming reacting force of
spring, which drives main
contact to close, switches on
circuit. AUKSiliary junction
acts accordingly.
4
Therm
al
relay
Thermal relay is usually
composed by overcurrent
element of bimetal. When
current is too high, bimetal
will generate heat that makes
it deform, offset and pry
up
protective contact. Control
loop of contactor disconnects
and power of main circuit
fails. Then,
temperature drops, bimetal
cools, circuit is switched on
again. However,
self-insurance control loop of
main circuit has disconnected
and it’s necessary to press
“Start” button again to start it.
Normal open main contact
Normal closed AUKSiliary contac
t
Normal open AUKSiliary contact
Armature
Sucking coil
Iron core
Arcing chamber
Reset rod
Setting knob of current
Thermal element
Contact
Driving push rod
