Service manual

ELECTRIC CONVEYOR OVENS - ELECTRICAL OPERATION
Pa
g
e 18 of 24
OVEN SEQUENCE OF
OPERATION
1. Conditions
A. Power switch off.
B. Belt switch off
C. Speed selection switch to desired position.
D. Hi
g
h limit thermostat closed.
E. Oven below set point.
F. Correct volta
g
e supplied to oven.
2. Power switch turned on.
A. 110VAC control volta
g
e to motor and fan
solid state relay, hi
g
h limit thermostat,
temperature control, speed control and DC
power supply module.
1) DC power supply ener
g
izes because
hi
g
h limit contacts are closed.
a. DC power supply module
supplies 21VDC control volta
g
e
to temperature control and
element solid state relays.
B. Motor and fan solid state relay ener
g
izes.
1) Blower motor(s) ener
g
ized.
2) Coolin
g
fan(s) ener
g
ized.
C. Power to temperature control.
1) If control is callin
g
for heat, 21VDC is
supplied to element solid state relays
and elements ener
g
ize.
2) Temperature displayed.
3. Belt switch turned on.
A. Drive motor ener
g
ized.
B. Display shows set speed.
4. Oven reaches set temperature.
A. Power is removed from the element solid
state relays.
1) Elements de-ener
g
ize.
5. Temperature control continues to cycle
elements on and off.