Omron MY3-D 24VDC General Purpose Relay Technical Guide
The Omron MY3-D 24VDC general purpose relay is a DC coil version of the MY3 relay family with built-in diode surge absorption. This makes it especially relevant for 24 VDC control panels where coil surge control is important. In relay circuits, switching off a DC coil can create a reverse voltage spike. A built-in diode helps absorb that surge, supporting cleaner operation around PLC outputs, transistor outputs, and sensitive control electronics.
Technical Specification Overview
Omron’s MY series specification table identifies MY3-D as a plug-in terminal model with built-in diode surge absorption for DC coil specification only. The table lists MY3-D under three-pole single-contact relay models. For the 24 VDC MY3-D specification group, Omron lists approximately 36.9 mA rated current, 650 ohms coil resistance, 3.2 H armature-off inductance, and 5.72 H armature-on inductance. :contentReference[oaicite:10]{index=10}
The same MY series documentation lists operating characteristics with a must-operate voltage of 80% maximum and a must-release voltage of 10% minimum for DC coils. Contact ratings for the MY series include 5 A at 250 VAC for resistive AC load and 5 A at 30 VDC for resistive DC load under listed conditions. :contentReference[oaicite:11]{index=11}
Why the Built-In Diode Matters
The main difference between a standard Omron MY3 24VDC relay and the Omron MY3-D 24VDC relay is surge absorption. When a DC relay coil is de-energized, the collapsing magnetic field can generate a voltage spike. In circuits driven by PLC transistor outputs or electronic controllers, that spike may stress the output device if not managed correctly. A diode-equipped relay provides built-in suppression, reducing the need for a separate external diode in many designs.
Because diode polarity matters, wiring must be checked carefully. Reversing polarity on a DC relay with a built-in diode can cause improper operation or circuit damage. This makes installation discipline especially important in maintenance environments.
Best-Fit Applications
The Omron MY3-D 24VDC relay is well suited for PLC interface circuits, control cabinet relay logic, signal isolation, equipment status outputs, and applications where DC coil surge suppression is preferred. The 3PDT contact arrangement allows three circuits to be switched from one coil, supporting compact control logic and reducing component count.
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Omron MY3-D 24VDC FAQ
What is the Omron MY3-D 24VDC relay?
It is a 24 VDC plug-in general purpose relay with three-pole switching and built-in diode surge absorption for the DC coil.
How is MY3-D different from MY3 24VDC?
The MY3-D version includes a built-in diode for coil surge absorption. The standard MY3 24VDC version does not provide that diode feature in the same way.
Why is diode surge absorption useful?
It helps control the voltage spike generated when a DC relay coil is switched off, which can help protect electronic outputs and reduce electrical noise.
Does polarity matter on the MY3-D 24VDC?
Yes. Because the relay includes a diode, correct DC polarity is important. The wiring diagram and socket terminal layout should be verified before power is applied.
What applications suit this relay?
It is suitable for PLC output interfaces, 24 VDC control panels, machine automation circuits, auxiliary control logic, alarm routing, and signal isolation tasks.
Can the MY3-D 24VDC relay replace a standard MY3 24VDC relay?
It may be possible in some circuits, but polarity, coil suppression behavior, socket compatibility, and control output requirements must be reviewed before substitution.