. The relays also have some rather conflicting specs printed righ on them...30A 250VAC/32VDC
Let's cut one open..
My gut says 7.5kW for that relay is high.But what does my gut know?Let's cut one open..
I did that a couple of years ago when they failed with my Peltier project. 12 volts dc at 3-4 amps. One failed shorted and failed open.The relay blades have very tiny balls for contacts. In my case the shorted unit had migrated materiel between the contacts. That kept the armature from moving. The open relay also had a build up of material between the contacts but, that was not conductive and kept the armature from closing.My experience shows these are cheap hobby relays not suitable for real world use. They are usable for signal switching and perhaps low level AC.Paul
What is wrong with that?It can switch 30A when the voltage is 250V AC but if you have DC then you can only switch 30A if the voltage is 32V or less.Because AC is constantly changing and reversing polarity the current "sticks the contact together" less than if it was DC.
I'm not sure the specs are "conflicting". If I'm remembering correctly, 1HP is about 750W so that's around 7A at 120V, plus some more for inefficiency, and it will depend on the actual mechanical load on the motor. But, the start-up current could be even higher than what you're measuring... If you are using a multi-meter it may be fast-enough.