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

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GAS OVEN THEORY OF OPERATION
FS/SI - The Flame Sensor/Spark Igniter consists of a copper-clad metal mounting plate, a ground
electrode, and two additional electrodes encapsulated in ceramic insulators. One of the insulated
electrodes has a 1/4” male spade welded to it while the other insulated electrode has a 3/16” male
spade welded to it. The rod with the 1/4” spade connects to the Spark Terminal on the Burner
Control (BC) via a spark wire. The end of this rod is positioned near the ground electrode in such
a way so as to create a small gap. When the high-voltage signal from the BC reaches the gap, it is
forced to jump the gap resulting in a spark.
Flame has the unique ability to rectify AC voltage and current into DC voltage and current.
The electrode with the 3/16” spade is positioned in such a way so that the electrode is inside the
flame envelope. A wire connects this electrode to Terminal S1 on the BC. A green ground wire is
attached to the copper-clad mounting plate, and connected to chassis ground inside the control box.
When flame is present, a DC current flow is detected by the BC. The amount of current flow is
determined by the position of the flame sensor and the size of the flame. The minimum current
flow to maintain operation is .7 µA.
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 energization (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.
M3 - The Flow Path Pressure Generating (FPPG) fan supplies combustion air for the Burner. It is
wired in parallel with M1 and will continue to operate for 30 minutes after S1 is turned off. A fil-
ter is provided to ensure clean air.