Automation Direct DL205 Manual page 34

3–10
I/O Wiring and Specifications
DL205 Installation and I/O Manual, Rev. B
Transient Voltage Suppressors (TVS or transorb) provide the best surge and
transient suppression of AC and DC powered coils, providing the fastest response
with the smallest overshoot.
Metal Oxide Varistors (MOV) provide the next best surge and transient
suppression of AC and DC powered coils.
For example, the waveform in the figure below shows the energy released when
opening a contact switching a 24 VDC solenoid. Notice the large voltage spike.
+24 VDC
+24 VDC
–324 VDC
This figure shows the same circuit with a transorb (TVS) across the coil. Notice that
the voltage spike is significantly reduced.
+24 VDC
–42 VDC
Use the following table to help select a TVS or MOV suppressor for your application
based on the inductive load voltage.
hhVendor / Catalog Type (TVS, MOV, Diode)
AutomationDirect 8 channel TVS
AutomationDirect 8 channel TVS
General Instrument TVS
Transient Voltage
TVS
Suppressors, LiteOn
TVS
Diodes; from DigiKey
Catalog; Phone:
Diode
1-800-344-4539
Harris Metal Oxide MOV
Varistors; from Newark
MOV
Catalog; Phone:
1-800-463-9275
Module Relay Contact
+24 VDC
Module Relay Contact
Inductive Load Voltage
24 VDC
110 VAC
110/120 VAC
220/240 VAC
12/24 VDC or VAC
12/24 VDC or VAC
110/120 VAC
220/240 VAC
–24 VDC
–24 VDC
Part Number
ZL–TD8–24
ZL–TD8–120
P6KE180CAGICT–ND
P6KE350CA
P6K30CAGICT–ND
1N4004CT–ND
V150LA20C
V250LA20C