Automationdirect.com DirectLOGIC DL205 Series User Manual page 63

Chapter 2: Installation, Wiring and Specifications
Types of Additional Transient Protection
1
DC Coils:
The most effective protection against transients from a DC coil is a flyback diode. A flyback
2
diode can reduce the transient to roughly 1V over the supply voltage, as shown in this example.
3
4
24 VDC
5
6
7
Many AutomationDirect socketed relays and motor starters have add-on flyback diodes that
plug or screw into the base, such as the AD-ASMD-250 protection diode module and
8
784-4C-SKT-1 socket module shown below. If an add-on flyback diode is not available for your
inductive load, an easy way to add one is to use AutomationDirect's DN-D10DR-A diode
terminal block, a 600VDC power diode mounted in a slim DIN rail housing.
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10
11
12
13
14
A
B
C
D
2–24
DL205 User Manual, 4th Edition, Rev. B
DC Flyback Circuit
+
_
Sourcing
Sinking
AD-ASMD-250
Protection Diode Module
Volts
Oscilloscope 30
25
20
15
10
5
0
-5
784-4C-SKT-1
Relay Socket
DN-D10DR-A
Diode Terminal Block