Gentherm 5220 Operating Manual page 25

28142 Rev 15
A 220 W Limiter/Converter (L/C) is available for use with the model 5220 TEG. It is intended
for use with model 5220 applications requiring nominal 24 VDC output. It consists of two
separate circuits operating together. The first is a shunt-type voltage limiter that regulates
the output of the generator. The second circuit is a DC-DC converter that switches the input
voltage to the customer's desired output voltage. It includes overload, short circuit and
reverse current protection, as well as a set of low voltage alarm contacts. The main parts of
the 220 W L/C are shown in Figure 7.
Protective (Voltage) Limiter: A voltage limiting circuit is incorporated into the 220 W L/C,
which limits input voltage helping achieve optimal performance from the TEG. It is factory
set at 16.0 V for the model 5220 TEG.
Voltage Converter: The voltage converter switches the Power Unit voltage to the customer's
voltage setting.
Current Limiter: Overload protection triggers when the load draws excess current. The
result is a proportional drop in output voltage, and fold-back current limiting.
Short circuit protection is also designed into the 220 W L/C. A 15-second short circuit will not
damage the generator or the L/C.
Blocking Diode: Reverse current protection is standard on the 220 W L/C. A diode in series
with the positive output prevents current from flowing back through the converter when the
generator is shut off.
Voltage Sensing Relay: Voltage Sensing Relay (VSR) provides a set of contacts to indicate
an alarm condition when the output voltage drops below a preset minimum.
Low voltages due to overloads, lack of fuel, or a faulty generator, are detected by a voltage
sensing circuit incorporated into the voltage limiter. When a low voltage condition is detected,
the Voltage Sensing Relay (VSR) with connections NC (normally closed), NO (normally open)
and COM (common) can be used to trigger an alarm or other processes. When the generator
is above the trip voltage, the connection between NO and COM is closed. If the generator is
below the trip voltage, then the connection between NO and COM is open, and the connection
between NC and COM is closed. The trip voltage is adjusted by the pot labeled "VSR Adjust"
on the VSR board as shown in Figure 8.
Gentherm Global Power Technologies
If extended short circuit durations are anticipated, an
in-line fuse should be placed on the output of the
CAUTION!
limiter converter. Use a 15 A slow blow for the model
5220-24 TEG.
PROCESS DESCRIPTION
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