Top Burner Ignition And Reignition System - Electrolux E36DF76EPS Service Manual

Top burner ignition and reignition system

The burner ignition and reignition system is made up
of the ignition switches, that are mounted to the top
burner valves,
gas igniter/re-igniter module
and an igniter mounted to each burner base.
When the shaft of the valve is rotated from the off posi-
tion the contacts of the igniter switch close and remain
closed as long as the burner is on. This connects L1 to
the module terminal for that burner. The module has
two jobs; first to ignite the burner and once the burner
has been ignited, to monitor the flame. When power is
applied to the module, inside the module two things
happened. First power is supplied to the step-up trans-
former, which in turn supplies power to the charging
circuit and second an electrical signal is generated and
applied to the igniter of the burner that is being ignited.
The output of the charging circuit is applied to all the
igniter's. The following explanation is how a simple ig-
nition system works. When L1 is applied to the primary
of the step-up transformer T1, the output voltage on the
secondary side of transformer is increased. Since AC
voltage is being applied to the transformer the ends of
the transformer will change polarity every half cycle. In
the drawing below, when the polarity of the transformer
secondary winding is negative at the top and positive at
the bottom current flows in the circuit form by the trans-
former secondary, diode D1, capacitor C1 and resistor
R1. This charges C1 negative on the top and positive
on the bottom. On the next half cycle, when the top of
the transformer secondary winding is positive and the
bottom is negative, the diode prevents current flow in
the circuit and prevents the capacitor from discharging.
At this point the capacitor also is prevented from dis-
charging through the circuit form by the capacitor, Ib1
(igniter bank one), the range chassis, Ib2 (igniter bank
2) and R1 by the dielectric of the air between the igniter's
and the burner heads. In this drawing the burner heads
are considered part of the range chassis. The capaci-
tor continues to charge every half cycle until the charge
on the capacitor is high enough to break down the re-
sistance of the air dielectric between the igniter tips and
burner heads. At that time an electric spark occurs
between all the igniter tips and the burner heads. This
allows current flow from the top of the capacitor to the
Ib1, across the electrical arc into the range chassis and
from the range chassis across the electrical arc into
Ib2, through the resistor to the other side of the capaci-
tor discharging the capacitor.
T1
This cycle continues until the burner is ignited. The
symbols Ib1 and Ib2 represents one half of the total top
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D1
Ib1
C1
R1
Ib2
RANGE
CHASSIS