XLT XD-9006A (GAS Oven Version – C, AVI Hood Version – C) - Manual (Page 10)

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GAS OVEN THEORY OF OPERATION
IC - The Ignition Control (IC) is powered by 24 VAC from the Transformer (XFMR). Incoming
power will be interrupted by the Temperature Control (TC) when the actual temperature rises
above the Maximum Operating Temperature (see Specification Sheet). When the IC receives
power, it initiates a pre-purge lighting sequence. A red LED will blink once after about 2-3 sec-
onds to give notification that the lighting sequence has started. After about 30 seconds, two events
occur; 1) a high-voltage electrical signal will be sent to the Flame Sensor/Spark Igniter (FS/SI)
from the Spark Terminal, and 2) a 24 VAC signal will be generated across Terminals V1 & V2.
The high voltage jumps across a gap in the FS/SI creating a spark that can be heard, although the
IC only produces this spark for four (4) seconds. One end of the Rectifier Plug is connected to
Terminals V1 & V2 through a Circuit Breaker (CB6). The Rectifier Plug rectifies the 24 VAC to
24 VDC. The other end of the Rectifier Plug is connected to Terminals 1 & 4 of the Main Valve
(V1-V2). The V1-V2 valve will open, allowing fuel to flow into the burner. When the two simul-
taneous events occur, fuel flow and spark, ignition should occur. When flame is sensed by the FS/
SI, a DC current is sent to Terminal S1 of the IC. The IC uses this DC current to prove ignition. A
minimum of .7 µA is required to maintain operation. If the Burner lights, the LED will not flash.
If the Burner fails to light, the LED will flash three (3) times, repeatedly, and the IC will not at-
tempt to re-light.
M1 – The Main Motor is a Permanent Split Capacitor (PSC), single phase, capacitor run motor and
has an internal centrifugal switch (S2). The motor is dual voltage and reversible. The voltage to
power the motor comes from the Cool Down Timer (R1), and the motor will continue to operate
for approximately 30 minutes after the main switch is turned off. There are no user serviceable
parts in the motor, and the bearings are permanently lubricated.
M2 - The Conveyor Motor (M2) is a brushless 24 VDC gear motor. The motor receives current
from the Conveyor Control (CC) through three (3) wires; 1) A black or “W” phase, 2) a white or
“V” phase, and 3) a red or “U” phase. They carry between 18 to 24 VDC. Each wire is energized
by the Conveyor Control (CC) in sequence to provide power to the individual stator coils which, in
turn, provide motor rotation.
To determine the rotors position and send this position to the controller, three (3) Hall Ef-
fect switches are utilized. They read the rotational information from a disc mounted on the rotor
assembly. This information is transmitted to the CC by three (3) wires; 1) an orange “U” phase
pole signal output, 2) a green “V” phase pole signal output, and 3) a green/white “W” phase pole
signal output. These are located in a plug that inserts into the CC. There are two (2) additional
wires in this plug; 1) a purple wire which is supply voltage for the pole sensor, and 2) a gray wire
that is ground.
The CC, using an internal logic circuit, energizes the stator coils to provide proper rotation
and sets the enerigization (phase) timing to obtain the desired belt speed set on the controller.
The motor drives an integral gear box that reduces the motor output speed to give the correct travel
time to the conveyor belt. The integral gear box is sealed and permanently lubricated with grease.
The ratio is 1/200.