What you're swapping into the socket
The Omron MY4N-D2 DC125 is a plug-in general purpose relay in the MY series, built around a 4PDT contact arrangement with a 125 VDC coil — four poles in one package, so a single socket handles a logic interlock, a status return, and two spares without stacking two DPDT relays. It draws roughly 0.9 W to hold the armature in, which matters on a 125 VDC rail — the DC coil is the slower-dropout side of this part versus the AC variants, so check the dropout time budget on any timing-sensitive interlock.
Contact ratings and what they govern
Maximum switching current is 3 A, with switching voltage rated to 250 VAC or 125 VDC — on the resistive side the contact carries 3 A at 220 VAC or 24 VDC, which lands at 660 VA / 72 W of switching power. Inductive loads drop the envelope sharply: 0.8 A at 220 VAC and 1.5 A at 24 VDC, with inductive switching power capped at 176 VA / 36 W. The relay will switch the resistive number, but a solenoid, contactor coil, or DC motor winding needs to be sized against the inductive figures, not the headline 3 A. Minimum load is rated 1 mA at 1 VDC, so the same contact that powers a small solenoid still closes cleanly on a low-level logic return — useful when one relay is doing double duty as a pilot-duty output and a status feedback into a PLC input.
Operating envelope and panel placement
Operating temperature spans -55 to 70°C, which covers unheated cabinets and most outdoor enclosures without derating — the relay drops into a standard MY-series socket, so field replacement is a pull-and-push on the existing DIN-rail or panel-mount base.
Lifecycle status and compliance posture
RoHS compliance is confirmed, so the part ships into builds destined for the EU and other jurisdictions enforcing the restriction list; the MRO buyer specifying this for a retrofit does not need a separate compliance waiver for the lead-free build standard.