Omron MY3 24VAC General Purpose Relay Technical Guide
The Omron MY3 24VAC general purpose relay is a miniature plug-in relay intended for control circuits that use a 24 VAC coil supply. It is part of Omron’s MY relay range, a family built for general purpose switching in industrial panels, machine control systems, building automation equipment, and electrical interface circuits. The MY3 format provides three-pole switching, making it useful when one control signal must operate multiple isolated circuits.
Core Technical Profile
The MY3 relay family uses plug-in terminals and is commonly selected for socket-based panel installations. Omron’s MY specifications identify MY3 as a 3-pole single-contact plug-in terminal model. The MY series contact ratings include 5 A at 250 VAC for resistive AC loads and 5 A at 30 VDC for resistive DC loads under listed conditions. :contentReference[oaicite:3]{index=3}
For the 24 VAC coil version, Omron’s coil table lists 24 VAC data with rated current values of approximately 53.8 mA at 50 Hz and 46 mA at 60 Hz. The coil resistance reference value is 180 ohms, with coil inductance reference values of 0.69 H when the armature is off and 1.3 H when the armature is on. The must-operate voltage is specified as 80% maximum of rated voltage, while the must-release voltage for AC coils is 30% minimum. :contentReference[oaicite:4]{index=4}
Why 24 VAC Matters
Many control systems use 24 VAC where low-voltage AC control power is preferred. HVAC equipment, building automation panels, older machine controls, and transformer-fed control circuits often use this voltage. The Omron MY3 24VAC relay fits these environments by offering multi-pole switching while keeping the coil aligned with the existing control supply.
The 3PDT contact structure is especially helpful when a single control action needs to switch several functions at once. For example, one pole may drive a signal lamp, another may route a permissive signal, and the third may isolate an auxiliary circuit. This makes the relay practical for organized control logic without adding multiple separate relays.
Application Considerations
Before using the Omron MY3 24VAC relay, designers should verify socket compatibility, expected load current, switching voltage, load category, ambient temperature, and panel spacing. Inductive loads can create voltage spikes when switched, so suppression may be needed across coils, solenoids, or other reactive loads. The relay should also be installed in a way that reduces unnecessary vibration and mechanical stress.
For additional Omron component references, see Omron relay and automation products.
FAQ
What is the Omron MY3 24VAC relay?
It is a 24 VAC coil, plug-in, general purpose relay from the Omron MY series, designed for multi-circuit switching in control and automation systems.
What does the MY3 contact arrangement provide?
The MY3 format provides three changeover contact sets, allowing one coil to switch three separate circuits at the same time.
Where is a 24 VAC relay commonly used?
It is commonly used in HVAC controls, building automation panels, transformer-fed control circuits, machine controls, and auxiliary switching systems.
Is the Omron MY3 24VAC relay suitable for socket mounting?
Yes. MY3 relays are plug-in models and are normally installed with compatible relay sockets for easier replacement and cleaner wiring.
What should be checked before installation?
The main checks are coil voltage, contact rating, socket type, terminal layout, load type, ambient temperature, and whether surge suppression is needed.
Can this relay replace a 24 VDC relay?
No. A 24 VAC coil relay should not be used as a direct replacement for a 24 VDC coil relay unless the circuit supply is changed and compatibility is fully verified.