mxuteuk 2pcs HH54P DC 24V Coil 14 Pin 3A 4PDT LED Indicator Electromagnetic Power Relay, with Base, with DIN Rail Slotted Aluminum

The beauty of this package is you get two relays, and a DIN rail long enough to include both relays and some other DIN-rail components, such as diode and ground plane. The schematic for the relay is printed on the side, but is hard to read, as the printing is in black ink on a dark background. I popped the plastic cover off, put int in front of a white background, and photographed the relay pinout with my cellphone for easy reference (see attached photo).Note that this is the view of the relay contacts, as viewed from the bottom of the relay. The numbers match the barely visible numbers embossed on the socket next to the screw terminals. I had to use a flashlight to see them clearly.It would be nice if they included a paper slip with both the relay and socket pinouts in the package.

I purchased two of these relays to control a 2-phase pool pump and a 2-phase cleaner pump (7A draw on each leg). One look at the wire used between the lug of the relay and the contact made me decide not to risk the connection (in addition to one of the relays having a buzzing coil), so I returned these and got 30A contactors. I have seen through-hole relays which are rated at 8A, but even those pins looked thicker than the wire connecting the contact to the lug at the base of the relay.I think if you wanted to use these for lower voltage and/or current, they would be fine (assuming the coils don't buzz when energized). The LED indicator is a nice touch as well - to give visual indication that the coil is energized.

You get what you pay for. I'm probably going to return these and pay more to buy name brand relays from a reputable electronics supplier instead; it just doesn't seem worth the risk to save a few dollars on these.One of the two relays I ordered had a disconnected LED internally - pretty poor quality control. The LED and resistor had clearly pulled apart when they were being soldered at the factory, so they both had solder on them but were not attached to one another. A 10 second soldering job to fix (the clear cover is pretty easy to remove), but demonstrates a complete lack of quality control, which is worrying on a device rated to run at 110V and 10A.About that 10A rating: I'd be pretty worried about running these at 10A - the bonding wires from pins 5 and 6 to the movable contacts look pretty thin gauge and the connections to the copper/brass of the moving contact don't look great either.

Bought this one. Received in very good condition. I like the LED light that is on when the coil is on. Did a quick test to check if the speed to switch from one 120v power to another. My computer can survive without rebooting during switch. My computer's power supply is complaint to the standard EPS1U that requires the minimal hold-up time of 17 milli-seconds (not sure how long the hold-up time actually is). I do not know how fast this replay can do but fortunately it is fast enough to do a switch transfer before my computer's power supply hold-up finishes. I did multiple switch tests. All without any problem so far. Happy with it for now. Decide to buy one pair again to complete my fancy 3 dpdt relay automatic transfer switch.update: I completed my auto transfer switch that can switch between two power sources with a switch to control any one of the power source should be used as preferred one when electricity is on on both two sources. Have used it for a few months now without any problem. Only one time, the 10A inline fuse holder is broke (not the fuse) but the relays are good. (I probably should not use the plastic inline fuse holder to hold a 10A fuse on 120v power. I switched to use only 5A fuse and limit the current between 2A to 3A most of the time. Looks good.I bought one more pair to build two simple auto transfer switch for my TV, and other electronics. Looks good.

This is really two reviews, since I have very different experience with 4PDT vs DPDT versions.DPDT, 12vdc and 120vac coil voltages:These function well. I like the LED showing the relay is active (it is NOT bidirectional: pin 14 must be positive on dc version, as indicated on the circuit diagram on the dust cover), and the socket and DIN rail included are a nice touch (they even include screws for the rails!). I've been using them (so far) prototyping a new auto/manual generator controller for my PV system, and so far they run fault-free. Warm slightly during long (hours) activation time. DC versions do NOT have integral reverse-biased clamping diodes. No complaints, 4 stars. (I'll update to 5 if they hold up.)4PDT 120vac voltage:I had to return my order, because 50% of the normally closed contacts showed open circuit 50% of the time (both relays)! Still giving average 3 stars, because the relays are a great (and classic) design (I have 12vdc and 120vac 2-pole relays from vendor that are fine, work flawlessly), I like the LED showing the relay is active, and the socket and DIN rail included are a nice touch. But with a 4-pole relay, all 4 normally closed (NC) contacts have to reliably provide closed circuits when the relay is deactivated, and these fell far short of that requirement. Great price; terrible performance; 1 star for 4-pole.UPDATE:Amazon refunded with no return required, so with the 4PDTs being junk anyway, figured I had nothing to loose attempting to track down the continuity issue. Increased spring tension by removing a loop from the armature spring: no improvement! Finally removed armature and inspected contacts, and what is clearly visible is the poor alignment of the 4 armature contacts (see photo). Visual inspection while hand-operating the armature confirms that some contacts close well before others, such that the most misaligned do not reliably achieve sufficient contact to pass closed-circuit test on NC side, even with the increased spring tension. DPDT types are demonstrably more reliable, and probably less susceptible perhaps because they only have 2 contact armatures (half the tension, and being 3-point mechanically, they can rock a bit to seat correctly). These 120vac 4-poles have "AIPUG" on the dust cover, and a model #HH54P-L.Bottom line: 2-poles seem fine; manufacturer needs more precision in armature contact alignment for the 4-pole relays, and better quality control of circuit-closure reliability. Test them carefully before putting them in service!