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DC contactor
Use 2-pole or 3-pole contactor
DC contactor

DC contactor
2-pole or 3-pole contactor wired for DC loads
DC direct current is different than AC alternating current.

AC current oscillates back and forth on the wire each time generator rotates 50-60 times per second. US and Americas the standard is 60 cycles. Europe Asia Africa etc 50 cycles. With AC electricity, the electrons actually change direction. At the midpoint in each oscillation, the voltage crosses zero volts, making it easier to extinguish the arc caused by disconnection of a switch.
DC current does not oscillate. Instead, the electrons flow through circuit at same direction and voltage at all times.
When AC voltage hits zero volts, then the arc or spark or heat is easy to extinguish.
Result: AC switchgear, like contactors, last million of repetitions without melting the points.
High voltage DC is different. When high voltage DC is turned off, the electrons keep pushing because the voltage never reaches zero.
Result: DC voltage causes arc or spark or heat that is difficult to stop. Basically the electrons keep piling up and pushing the arc across the points of the contactor.
DC switchgear must be rated for DC voltages, and be capable of extinguishing DC arc.
Illustration shows one method of extinguishing DC arc using 3-pole contactor. The circuit has 3 parallel switches on the positive wire, thus helping to stop the arc better than 1 switch
With a 4-pole contactor, 3 poles can be used to turn off Positive, and 1 pole to turn off Negative.
To help eliminate arcs, add a resistor in parallel with inductive winding. Example of inductive winding is motor load
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DC power relays with 12-24 VDC coil

>Full on-off contacts/ 12 or 24 volt DC coil
>250 volt / 25 amp DC load
>250V x 25 amp = 6250 watt
>Connect 12 or 24 volt DC to terminals 3-4
>Connect load to terminals 1-2
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AC contactor instead:
>When 1st pole burns out, move wires to 2nd pole, etc
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