Control Relay Switching Capacity

[funky_gorilla]

Hi, I have a question regarding a DC switching maximum capacity. I am reading a data sheet and it mentions that the DC switching capacity is rated as below:

Load side Rated switching voltage 250 V AC Continuous current 16 A .1) For full continuous current (16 A), relay connections 11–21, 12–22 and 14–24 must be bridged. Max. switching frequency at rated load 0.1 Hz AC switching capacity (resistive), max. 4000 VA DC switching capacity (resistive), max. 384 W @ 24 V Contact design CO contact Contact material AgNi Contact material product selector non-gold-plated contacts Contact type 1 CO contact (AgNi) Mechanical service life AC coil 5 x 106 switching cycles, DC coil 10 x 106 switching cycles Number of contacts 1

The thing is, we plan to have a solar panel rated at 440W @ 48Volts. I guess the question we have is for 384W@24V (16A) capacity, are we wanting to avoid surpassing the wattage, or the current per the specification on the relay?

 

[jim dungar]

The thing is, we plan to have a solar panel rated at 440W @ 48Volts. I guess the question we have is for 384W@24V (16A) capacity, are we wanting to avoid surpassing the wattage, or the current per the specification on the relay?

You definitely do not want to exceed the voltage rating of the contacts. They do not have enough electrical clearance to break more than 24VDC. Some manufacturers get around this by putting multiple contacts in series.

You also do not want to exceed the current or wattage rating based on the voltage across the contacts.

 

[funky_gorilla]

Thank you very much Jim, that makes perfect sense.