Choosing a relay for 1kW switching

by Bhuvnesh   Last Updated August 14, 2019 06:25 AM

I am making a project for some practical application. I require to use a relay which can control up to 1kW AC power. Though there are cheap 5V relays available with about 220VAC and 10A rating which satisfy the requirement but I highly doubt their truthfulness and lifetime. At the same time I want to make the project cheap so I want to avoid costlier ones. Can someone please suggest a good compromise between the choices. And how far can I probably go with the ratings of cheap ones(rough idea).



Answers 1


Though there are cheap 5V relays available with about 220VAC and 10A rating which satisfy the requirement but I highly doubt their truthfulness and lifetime

A good relay is not cheap. It's cost anywhere between $2-4 and has a usable life of around 50k operations or less. (more for signal relays)
To prevent arcing when opening a strong spring is used, requiring a higher current to compress when closing. Coil power will go up with contact rating.
For example, an Omron G5Q relay available in a high capacity version SPST-NO is capable of switching max 10A with 250Vac resistive load.

For actual 10A rated breaking current you'd want to search above 250 Vac maximum contact rating. My example is 277 Vac.

This relay specifies 25,000 operations at 10 A with 250 VAC resistive load.

A solid state relay from Crydon for example will have infinite operations, but is $25 and requires a heatsink.
Running your own SSR with a triac can be cheaper than that, if the application allows it.

Mechanical relays are not that expensive after all...

Jeroen3
Jeroen3
August 14, 2019 06:03 AM

Related Questions





Coil Voltage Rating of Relay

Updated August 15, 2019 09:25 AM

Power supply and switching of relay?

Updated August 15, 2017 07:25 AM