BlueStars Ultra Durable 4 Pole Contactor 40 Amp 120 VAC Coil - Compatible for Relays, Air Conditioner, Heat Pump, Refrigeration Systems - Pack of 2

I was a little concerned about the low cost, but the quality was just as good as the expensive ones from the big name brand. In fact, this one had more wiring options. I’d buy this again in a minute.

I am not at all familiar with this brand. So before trusting it enough to just put it in service and hope for the best, I wanted to do some minor evaluating.While I am not familiar with these, I am quite familiar with many other brands. I do not think I should call names here, but I have experience with many of the well known flavors from 15-100 amp while working as an industrial electrician in a manufacturing facility.I am not going to subject them to abuse just to test them, but I did disassemble them and I checked for things I would look for in any such relay.I do like that there are two male 1/4" stake-on type connectors for each contact and the coil as well. Depending on what you are using this for, you do have the option to use them AND the screw terminal for the contacts. However, the coil only has 1/4" connectors, and that is the only strike I can find against them. Those internal coil wires are also wrapped and soldered onto the terminal posts. The iron core has a nice rubber cushion on the bottom to help when de-energized.In my opinion, the contacts are a good size for this current, and they are polished smooth. I dd not remove the contacts, I only looked at them. All 4 contacts are the same size, and should carry the same amount of current. Using my ohm meter across each set of contacts while energized, I got as close to a "0" ohm reading as you can hope for, and I do not mean that sarcastically.When energized, there is a very solid closing of the contacts. No coil chatter at all, no hum or vibration.The fit and finish are as good as any. Everything moves easily and there is an internal guide to keep everything aligned. If these were subjected to manufacturing plant environment, I would have only the reservation that the walls of the body material seemed (I did not measure them) slightly thinner than some of the more well known. However, they are likely adequate as I have seldom seen the walls or body of a relay give a problem.While I can not speak for longevity, I would not hesitate to give these a try.

I picked these up for a custom test project attempting to gang two standard gasoline generators together to increase output at low cost. This requires four pole contactors so one or both generators can be cut in/out of the mains circuit quickly when the are in phase, or when one of the engines cuts out, to prevent damage to the generators or engines. The generators I'm testing with are 6000W peak, so only about 20A output, so these 40A contactors give me a good bit of safety headroom. They work well for what I need, and meet the cut in/out speeds required for the project. Haven't gotten everything quite ready for full testing, but from what I have done, these perform very well and I'm quite pleased with them. For their intended use for AC units, they should work very well if you are needing to replace one.

Ran both for 3 days before one failed. One set of contacts came loose jamming sideways in its mount. I have replaced many contactors over the years but never seen one fail like this one but I have always used a name brand commercial contactor in the past.