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I need help understanding what these ratings mean. This is a general purpose relay. I'm confused. The Turn on/Off voltages are these voltages that need to be provided to the relay to turn the relay on and off? Is the Coil voltage the voltage that I can safely switch on this relay? Is the Contact Rating Current the current that this relay can handle?

Coil Current 4.5mA
Coil Voltage 48VDC

Turn On Voltage (Max) 33.6 VDC
Turn Off Voltage (Min) 2.4 VDC

Contact Rating (Current) 6A
Switching Voltage 400VAC - Max

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    \$\begingroup\$ Typically the numbers as given are at a coil temperature of 25°C, so you will need to give it more than 33.6VDC to get it to turn on if it is hot, and it could stay on with less than 2.4VDC if it is cold. \$\endgroup\$
    – Spehro 'speff' Pefhany
    Commented Jul 21, 2017 at 17:36
  • \$\begingroup\$ Given the low coil current and wide range between Turn On and Turn Off voltages, I suspect that this may be a solid state relay rather than a mechanical relay - what is the make and part number? \$\endgroup\$
    – Peter Bennett
    Commented Jul 22, 2017 at 2:16

1 Answer 1

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Coil current and voltage are what the signal side of the relay need in order to actuate the mechanical switch on the other side, which is called the contact. So you need to give the relay 4.5mA at 33.6+ VDC (maximum required voltage to switch) and it will switch up to 6A at 400VAC. I believe that the 2.4 VDC is the minimum point at which the coil will release the contact - that is, your low level must be less than 2.4 VDC.

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  • \$\begingroup\$ +1 for good description. I'd also point out it is rated for 6A AC... Not just 6A. 6A DC may burn out the relay. \$\endgroup\$
    – Trevor_G
    Commented Jul 21, 2017 at 16:03
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    \$\begingroup\$ Yes, good catch. I believe relay contacts are often abused in low power applications, but the coil and relay side are AC/DC specific when you are picking out a relay. \$\endgroup\$
    – Will
    Commented Jul 21, 2017 at 16:07

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