I was looking to specify a relay to control a 120V branch circuit powering a duplex receptacle, when looking at the maximum load the relay can under it has multiple ratings 1hp @ 120V, 20A ballast, 20A resistive, 1200w tungsten, and 740 pilot duty. My question is what is a ?tungsten? and ?pilot duty??
Relay contact ratings?
- Thread starter Mike01
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LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
More specifically, tungsten loads have very high inrush currents, which are almost as hard on contacts as opening under load is.
- Location
- Wisconsin
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- PE (Retired) - Power Systems
Many people confuse relays and contactors. Relays are usually not rated for very high make (turn on/inrush) and break (turn off/open) ratings, even though their continuous current ratings can be fairly high. Contactors are often rated to make and breaker currents that are many times their continuous current rating (like during motor starting). Rarely do relays exceed 15A continuous while 'definite purpose' contactors are usually never lower than 20A.
If you want to feed a 120V duplex receptacle you really should be using a contactor.
If you want to feed a 120V duplex receptacle you really should be using a contactor.
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